| Aaa water treader bug | Cavaticovelia aaa | Species of Concern | Wherever found | |
| Aalbu's cave pseudoscorpion | Archeolarca aalbui | Species of Concern | Wherever found | |
| Aardhals springsnail | Pyrgulopsis aardahli | Species of Concern | Wherever found | |
| Aase's onion | Allium aaseae | Species of Concern | Wherever found | |
| Abajo daisy | Erigeron abajoensis | Resolved Taxon | Wherever found | |
| Abbott's booby | Papasula (=Sula) abbotti | Endangered | Wherever found | 06-14-1976 |
| Abbott's bush-mallow | Malacothamnus abbottii | Species of Concern | Wherever found | |
| Abellan hydropsyche caddisfly | Ceratopsyche abella | Species of Concern | Wherever found | |
| Aboriginal Prickly-apple | Harrisia (=Cereus) aboriginum (=gracilis) | Endangered | | 11-25-2013 |
| Absaroka beardtongue | Penstemon absarokensis | Resolved Taxon | Wherever found | |
| Acadian Flycatcher | Empidonax virescens | Species of Concern | Wherever found | |
| A Cave Obligate amphipod | Stygobromus obscurus | Resolved Taxon | Wherever found | |
| A Cave Obligate Harvestman | Cryptobunus cavicolus | Resolved Taxon | Wherever found | |
| A Cave Obligate Harvestman | Hesperonemastoma packardi | Resolved Taxon | Wherever found | |
| A Cave Obligate Pseudoscorpion | Tyrannochthonius troglodytes | Resolved Taxon | Wherever found | |
| A Cave Obligate Shrimp | sphaeromicola moria | Resolved Taxon | Wherever found | |
| Acklins ground iguana | Cyclura rileyi nuchalis | Threatened | Wherever found | 06-22-1983 |
| Acoma fleabane | Erigeron acomanus | Resolved Taxon | Wherever found | |
| Acorn rams-horn | Planorbella multivolvis | Species of Concern | Wherever found | |
| Acornshell | Epioblasma haysiana | Resolved Taxon | Wherever found | |
| Acuña Cactus | Echinomastus erectocentrus var. acunensis | Endangered | Wherever found | 10-31-2013 |
| Acute elimia | Elimia acuta | Under Review | Wherever found | |
| Addax | Addax nasomaculatus | Endangered | Wherever found | 09-02-2005 |
| Adder's-mouth | Malaxis brachypoda | Species of Concern | Wherever found | |
| Addison's virgin's bower | Clematis addisonii | Species of Concern | Wherever found | |
| Adobe desert-parsley | Lomatium concinnum | Species of Concern | Wherever found | |
| Adobe navarretia | navarretia nigelliformis ssp. nigelliformis | Species of Concern | Wherever found | |
| Adobe sanicle | Sanicula maritima | Species of Concern | Wherever found | |
| Adobe yampah | Perideridia pringlei | Resolved Taxon | Wherever found | |
| Adriatic sturgeon | Acipenser naccarii | Endangered | Wherever found | 09-04-2014 |
| Adytum megalagrion damselfly | Megalagrion adytum | Species of Concern | Wherever found | |
| A`e | Zanthoxylum dipetalum var. tomentosum | Endangered | Wherever found | 10-10-1996 |
| A`e | Zanthoxylum hawaiiense | Endangered | Wherever found | 03-04-1994 |
| A`e | Zanthoxylum oahuense | Endangered | Wherever found | 10-18-2012 |
| A`e | Zanthoxylum semiarticulatum | Resolved Taxon | Wherever found | |
| A`e | Zanthoxylum skottsbergii | Resolved Taxon | Wherever found | |
| A Freshwater Snail | Pyrgulopsis bedfordensis | Resolved Taxon | Wherever found | |
| African coelacanth | Latimeria chalumnae | Threatened | Tanzanian Distinct Population Segment (DPS) of African coelacanth | 04-28-2016 |
| African dwarf crocodile | Osteolaemus tetraspis tetraspis | Endangered | Wherever found | 06-14-1976 |
| African elephant | Loxodonta africana | Threatened | Wherever found | 06-11-1978 |
| African penguin | Spheniscus demersus | Endangered | Wherever found | 10-29-2010 |
| African slender-snouted crocodile | Crocodylus cataphractus | Endangered | Wherever found | 03-28-1972 |
| African viviparous toads | Nectophrynoides spp. | Endangered | Wherever found | 06-14-1976 |
| African wild ass | Equus africanus | Endangered | Wherever found | 06-02-1970 |
| African wild dog | Lycaon pictus | Endangered | Wherever found | 01-23-1984 |
| Agate rocksnail | Leptoxis clipeata | Resolved Taxon | Wherever found | |
| Agave Threeband | Humboldtiana agavophila | Resolved Taxon | Wherever found | |
| `Ahakea | Bobea sandwicensis | Resolved Taxon | Wherever found | |
| `Ahakea | Bobea timonioides | Species of Concern | Wherever found | |
| Ahart's dwarf rush | Juncus leiospermus var. ahartii | Species of Concern | Wherever found | |
| Ahart's whitlow-wort | Paronychia ahartii | Species of Concern | Wherever found | |
| `Ahinahina | Argyroxiphium sandwicense ssp. macrocephalum | Threatened | Wherever found | 05-15-1992 |
| `Ahinahina | Argyroxiphium sandwicense ssp. sandwicense | Endangered | Wherever found | 03-21-1986 |
| Ahinahina long-horned beetle | Plagiithmysus swezeyanus | Species of Concern | Wherever found | |
| Aholehole Kai | Kuhlia sandvicensis | Not Listed | | |
| Aholehole Mauka | Kuhlia xenura | Not Listed | | |
| A Hornwort | Aspiromitus appalachianus | Species of Concern | | |
| `Aiakeakua, popolo | Solanum sandwicense | Endangered | Wherever found | 02-25-1994 |
| `Aiea | Nothocestrum breviflorum | Endangered | Wherever found | 03-04-1994 |
| `Aiea | Nothocestrum latifolium | Endangered | Wherever found | 10-31-2016 |
| `Aiea | Nothocestrum longifolium | Resolved Taxon | Wherever found | |
| `Aiea | Nothocestrum peltatum | Endangered | Wherever found | 02-25-1994 |
| Ajo rock-daisy | Perityle ajoensis | Resolved Taxon | Wherever found | |
| Akekee | Loxops caeruleirostris | Endangered | Wherever found | 05-13-2010 |
| akiapolaau | Hemignathus wilsoni | Endangered | Wherever found | 03-11-1967 |
| Akikiki | Oreomystis bairdi | Endangered | Wherever found | 05-13-2010 |
| `Akohekohe (crested honeycreeper) | Palmeria dolei | Endangered | Wherever found | 03-11-1967 |
| `Akoko | Chamaesyce arnottiana | Species of Concern | Wherever found | |
| `Akoko | Chamaesyce atrococca | Species of Concern | Wherever found | |
| `Akoko | Chamaesyce celastroides tomentella | Species of Concern | Wherever found | |
| `Akoko | Chamaesyce olowaluana | Species of Concern | Wherever found | |
| `Akoko | Chamaesyce remyi hanaleiensis | Resolved Taxon | Wherever found | |
| `Akoko | Chamaesyce skottsbergii vaccinioides | Species of Concern | Wherever found | |
| `Akoko | Chamaesyce sparsiflora | Species of Concern | Wherever found | |
| `Akoko | Euphorbia celastroides var. kaenana | Endangered | Wherever found | 10-29-1991 |
| `Akoko | Euphorbia deppeana | Endangered | Wherever found | 03-28-1994 |
| `Akoko | Euphorbia eleanoriae | Endangered | Wherever found | 05-13-2010 |
| `Akoko | Euphorbia haeleeleana | Endangered | Wherever found | 10-10-1996 |
| `Akoko | Euphorbia herbstii | Endangered | Wherever found | 10-10-1996 |
| `Akoko | Euphorbia kuwaleana | Endangered | Wherever found | 10-29-1991 |
| `Akoko | Euphorbia remyi var. kauaiensis | Endangered | Wherever found | 05-13-2010 |
| `Akoko | Euphorbia remyi var. remyi | Endangered | Wherever found | 05-13-2010 |
| `Akoko | Euphorbia rockii | Endangered | Wherever found | 10-10-1996 |
| `Akoko | Euphorbia skottsbergii var. skottsbergii | Endangered | Wherever found | 08-24-1982 |
| 'Akoko | Euphorbia halemanui | Endangered | Wherever found | 05-13-1992 |
| `aku | Cyanea tritomantha | Endangered | Wherever found | 11-29-2013 |
| `aku`aku | Cyanea platyphylla | Endangered | Wherever found | 10-10-1996 |
| Akupa Sleeper, `O`Opu Akupa | Eleotris sandwicensis | Not Listed | | |
| Ala`a | Pouteria hotteana | Species of Concern | Wherever found | |
| Ala`a | Pouteria sandwicensis | Resolved Taxon | Wherever found | |
| `Ala `ala wai nui | Peperomia subpetiolata | Endangered | Wherever found | 06-27-2013 |
| Ala balik (trout) | Salmo platycephalus | Endangered | Wherever found | 06-02-1970 |
| Alabama beach mouse | Peromyscus polionotus ammobates | Endangered | Wherever found | 06-06-1985 |
| Alabama Canebrake Pitcher Plant | Sarracenia rubra ssp. alabamensis | Endangered | Wherever found | 03-10-1989 |
| Alabama Cave crayfish | Cambarus jonesi | Not Listed | Wherever found | |
| Alabama cavefish | Speoplatyrhinus poulsoni | Endangered | Wherever found | 10-11-1977 |
| Alabama cave shrimp | Palaemonias alabamae | Endangered | Wherever found | 09-07-1988 |
| Alabama channel darter | Percina sp. | Species of Concern | AL channel | |
| Alabama Clubshell | Pleurobema troschelianum | Resolved Taxon | Wherever found | |
| Alabama croton | Croton alabamensis alabamensis | Species of Concern | Wherever found | |
| Alabama glade cress | Leavenworthia alabamica ssp. alabamica | Resolved Taxon | Wherever found | |
| Alabama hickorynut | Obovaria unicolor | Proposed Endangered | Wherever found | |
| Alabama jamesianthus | Jamesianthus alabamensis | Species of Concern | Wherever found | |
| Alabama lampmussel | Lampsilis virescens | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Alabama lampmussel | Lampsilis virescens | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Alabama larkspur | Delphinium alabamicum | Resolved Taxon | Wherever found | |
| Alabama Leather Flower | Clematis socialis | Endangered | Wherever found | 09-26-1986 |
| Alabama Map turtle | Graptemys pulchra | Similarity of Appearance (Threatened) | Wherever found | |
| Alabama moccasinshell | Medionidus acutissimus | Threatened | Wherever found | 03-17-1993 |
| Alabama pearlshell | Margaritifera marrianae | Endangered | Wherever found | 10-10-2012 |
| Alabama rainbow | Villosa nebulosa | Under Review | Wherever found | |
| Alabama red-bellied turtle | Pseudemys alabamensis | Endangered | Wherever found | 06-16-1987 |
| Alabama sandwort | Arenaria alabamensis | Resolved Taxon | Wherever found | |
| Alabama shad | Alosa alabamae | Under Review | Wherever found | |
| Alabama spike | Elliptio arca | Under Review | Wherever found | |
| Alabama Spotted Bass | Micropterus henshalli | Not Listed | | |
| Alabama streak-sorus fern | Thelypteris pilosa var. alabamensis | Threatened | Wherever found | 07-08-1992 |
| Alabama sturgeon | Scaphirhynchus suttkusi | Endangered | Wherever found | 05-05-2000 |
| Alabama vertigo | Vertigo alabamensis | Species of Concern | Wherever found | |
| Alabama well amphipod | Stygobromus smithi | Species of Concern | Wherever found | |
| Alachua Light Fleeting Cave crayfish | Procambarus lucifugus ssp. alachua | Not Listed | Wherever found | |
| Alameda Island mole | Scapanus latimanus parvus | Species of Concern | Wherever found | |
| Alameda whipsnake (=striped racer) | Masticophis lateralis euryxanthus | Threatened | Wherever found | 12-05-1997 |
| Alamo beardtongue | Penstemon alamosensis | Species of Concern | Wherever found | |
| Alamosa satyr butterfly | Cercyonis meadii alamosa | Resolved Taxon | Wherever found | |
| Alamosa springsnail | Tryonia alamosae | Endangered | Wherever found | 09-30-1991 |
| Alani | Melicope adscendens | Endangered | Wherever found | 12-05-1994 |
| Alani | Melicope balloui | Endangered | Wherever found | 12-05-1994 |
| Alani | Melicope christophersenii | Endangered | Wherever found | 10-18-2012 |
| Alani | Melicope cruciata | Species of Concern | Wherever found | |
| Alani | Melicope degeneri | Endangered | Wherever found | 05-13-2010 |
| Alani | Melicope haleakalae | Species of Concern | Wherever found | |
| Alani | Melicope haupuensis | Endangered | Wherever found | 02-25-1994 |
| Alani | Melicope hawaiensis | Resolved Taxon | Wherever found | |
| Alani | Melicope hiiakae | Endangered | Wherever found | 10-18-2012 |
| Alani | Melicope kavaiensis | Resolved Taxon | Wherever found | |
| Alani | Melicope knudsenii | Endangered | Wherever found | 02-25-1994 |
| Alani | Melicope lydgatei | Endangered | Wherever found | 03-28-1994 |
| Alani | Melicope macropus | Resolved Taxon | Wherever found | |
| Alani | Melicope makahae | Endangered | Wherever found | 10-18-2012 |
| Alani | Melicope mucronulata | Endangered | Wherever found | 05-15-1992 |
| Alani | Melicope munroi | Endangered | Wherever found | 09-03-1999 |
| Alani | Melicope nealae | Species of Concern | Wherever found | |
| Alani | Melicope obovata | Resolved Taxon | Wherever found | |
| Alani | Melicope orbicularis | Resolved Taxon | Wherever found | |
| Alani | Melicope ovalis | Endangered | Wherever found | 12-05-1994 |
| Alani | Melicope ovata | Resolved Taxon | Wherever found | |
| Alani | Melicope pallida | Endangered | Wherever found | 02-25-1994 |
| Alani | Melicope paniculata | Endangered | Wherever found | 05-13-2010 |
| Alani | Melicope puberula | Endangered | Wherever found | 05-13-2010 |
| Alani | Melicope quadrangularis | Endangered | Wherever found | 02-25-1994 |
| Alani | Melicope reflexa | Endangered | Wherever found | 10-08-1992 |
| Alani | Melicope saint-johnii | Endangered | Wherever found | 10-10-1996 |
| Alani | Melicope sandwicensis | Resolved Taxon | Wherever found | |
| Alani | Melicope wailauensis | Species of Concern | Wherever found | |
| Alani | Melicope zahlbruckneri | Endangered | Wherever found | 10-10-1996 |
| Alaotra Grebe | Tachybaptus rufolavatus | Endangered | Wherever found | 01-12-1995 |
| Alaskan glacier buttercup | Ranunculus glacialis ssp. alaskensis | Not Listed | | |
| Alaska rein orchid | Platanthera unalascensis maritima | Resolved Taxon | Wherever found | |
| Albermarle crayfish | Procambarus medialis | Species of Concern | Wherever found | |
| Aldabra Warbler (old world warbler) | Nesillas aldabranus | Endangered | Wherever found | 01-12-1995 |
| Aleutian Canada goose | Branta canadensis leucopareia | Recovery | Wherever found | 03-11-1967 |
| Aleutian chickweed | Cerastium aleuticum | Resolved Taxon | Wherever found | |
| Aleutian saxifrage | Saxifraga aleutica | Resolved Taxon | Wherever found | |
| Aleutian shield fern | Polystichum aleuticum | Endangered | Wherever found | 02-17-1988 |
| Aleutian Tern | Onychoprion aleuticus | Not Listed | Wherever found | |
| Aleutian wormwood | Artemisia aleutica | Resolved Taxon | Wherever found | |
| alewife | Alosa pseudoharengus | Status Undefined | Wherever found | |
| Alewife Floater | Utterbackiana implicata | Not Listed | | |
| Alexander Archipelago wolf | Canis lupus ligoni | Resolved Taxon | Wherever found | 07-27-2021 |
| Alexander's rhyacophilan caddisfly | Rhyacophila alexanderi | Species of Concern | Wherever found | |
| Alexander's rock-aster | Eurybia avita | Species of Concern | Wherever found | |
| Algerian nuthatch | Sitta ledanti | Endangered | Wherever found | 01-12-1995 |
| Algodoncillo | Psiguria cookiana | Species of Concern | Wherever found | |
| Algodones croton jewel beetle | Agrilus harenus | Resolved Taxon | Wherever found | |
| Algodones Dunes sunflower | Helianthus niveus tephrodes | Species of Concern | Wherever found | |
| Algodones white wax jewel beetle | Prasinalia imperialis | Resolved Taxon | Wherever found | |
| Algondones sand jewel beetle | Lepismadora algodones | Resolved Taxon | Wherever found | |
| Alifan Tree snail | Partula salifana | Species of Concern | Wherever found | |
| A Liverwort | Porella wataugensis | Species of Concern | | |
| Alkali mariposa lily | Calochortus striatus | Species of Concern | Wherever found | |
| Alkali milk-vetch | Astragalus tener var. tener | Species of Concern | Wherever found | |
| Alkali skipper | Pseudocopaeodes eunus eunus | Not Listed | Wherever found | |
| Alleghany plum | Prunus alleghaniensis | Species of Concern | Wherever found | |
| Alleghany snaketail | Ophiogomphus incurvatus alleghaniensis | Status Undefined | Wherever found | |
| Alleghany woodrat | Neotoma magister | Resolved Taxon | Wherever found | |
| Allegheny cave amphipod | Stygobromus allegheniensis | Resolved Taxon | Wherever found | |
| Allen's 13-lined ground squirrel | Spermophilus tridecemlineatus alleni | Species of Concern | Wherever found | |
| Allen's big-eared bat | Idionycteris phyllotis | Species of Concern | Wherever found | |
| Allen's Cay iguana | Cyclura cychlura inornata | Threatened | Wherever found | 06-22-1983 |
| Allen's Hummingbird | Selasphorus sasin | Species of Concern | Wherever found | |
| Alligator Gar | Atractosteus spatula | Not Listed | | |
| Alligator snapping turtle | Macrochelys temminckii | Proposed Threatened | Wherever found | |
| almaco jack | Seriola rivoliana | Not Listed | | |
| Alpine bluet | Houstonia caerulea faxonorum | Resolved Taxon | Wherever found | |
| Alpine braya | Braya humilis ventosa | Resolved Taxon | Wherever found | |
| Alpine County cryptantha | Cryptantha crymophila | Resolved Taxon | Wherever found | |
| Alpine Mountainsnail | Oreohelix alpina | Resolved Taxon | Wherever found | |
| Alpine streptanthus | Streptanthus gracilis | Resolved Taxon | Wherever found | |
| Alsea ochrotrichian micro caddisfly | Ochrotrichia alsea | Resolved Taxon | Wherever found | |
| Altamaha arc-mussel | Alasmidonta arcula | Not Listed | Wherever found | |
| Altamaha lance | Elliptio shepardiana | Species of Concern | Wherever found | |
| Altamaha shiner | Cyprinella xaenura | Not Listed | Wherever found | |
| Altamaha Spinymussel | Elliptio spinosa | Endangered | Wherever found | 11-10-2011 |
| Altamira Oriole | Icterus gularis | Species of Concern | Wherever found | |
| Alverson's foxtail cactus | Coryphantha vivipara alversonii | Species of Concern | Wherever found | |
| Alvord chub | Siphateles alvordensis | Species of Concern | Wherever found | |
| Alvord cutthroat trout | Oncorhynchus clarki ssp. | Resolved Taxon | Alvord | |
| Ama (Black Mullet) | Mugil cephalus | Not Listed | | |
| Amador rush-rose | Helianthemum scoparium | Resolved Taxon | Wherever found | |
| Amak song sparrow | Melospiza melodia amaka | Resolved Taxon | Wherever found | |
| Amak tundra vole | Microtus oeconomus amakensis | Species of Concern | Wherever found | |
| Amargosa Canyon speckled dace | Rhinichthys osculus ssp. | Species of Concern | Amargosa Canyon | |
| Amargosa naucorid | Pelocoris shoshone amargosa | Resolved Taxon | Wherever found | |
| Amargosa niterwort | Nitrophila mohavensis | Endangered | Wherever found | 05-20-1985 |
| Amargosa penstemon | Penstemon fruticiformis amargosae | Species of Concern | Wherever found | |
| Amargosa Pupfish | Cyprinodon nevadensis | Not Listed | | |
| Amargosa River Pupfish | Cyprinodon nevadensis amargosae | Not Listed | | |
| Amargosa southern pocket gopher | Thomomys umbrinus amargosae | Resolved Taxon | Wherever found | |
| Amargosa speckled dace | Rhinichthys nevadensis nevadensis | Under Review | | |
| Amargosa toad | Bufo nelsoni | Under Review | Wherever found | |
| Amargosa tryonia | Tryonia variegata | Resolved Taxon | Wherever found | |
| Amargosa vole | Microtus californicus scirpensis | Endangered | Wherever found | 11-15-1984 |
| Amarillo mato | Caesalpinia culebrae | Species of Concern | Wherever found | |
| A Mayfly | Baetodes alleni | Resolved Taxon | Wherever found | |
| Amazonian manatee | Trichechus inunguis | Endangered | Wherever found | 06-02-1970 |
| Amber darter | Percina antesella | Endangered | Wherever found | 08-05-1985 |
| Ambiguous eopenthes click beetle | Eopenthes ambiguus | Species of Concern | Wherever found | |
| American alligator | Alligator mississippiensis | Similarity of Appearance (Threatened) | Wherever found | 03-11-1967 |
| American Avocet | Recurvirostra americana | Species of Concern | | |
| American badger | Taxidea taxus | Species of Concern | Wherever found | |
| American Bison | Bison bison | Not Listed | | |
| American bittern | Botaurus lentiginosus | Species of Concern | Wherever found | |
| American black bear | Ursus americanus | Resolved Taxon | U.S.A. (LA, all counties; MS, TX, only within the historic county range of the Louisiana black bear) | 01-07-1992 |
| American Brook Lamprey | Lethenteron appendix | Not Listed | | |
| American bumble bee | Bombus pensylvanicus | Under Review | | |
| American burying beetle | Nicrophorus americanus | Experimental Population, Non-Essential | In southwestern Missouri, the counties of Cedar, St. Clair, Bates, and Vernon. | 07-22-2011 |
| American burying beetle | Nicrophorus americanus | Threatened | Wherever found, except where listed as an experimental population | 07-13-1989 |
| American chaffseed | Schwalbea americana | Endangered | Wherever found | 09-29-1992 |
| American chestnut | Castanea dentata | Status Undefined | | |
| American chestnut nepticulid moth | Ectodemia castaneae | Species of Concern | Wherever found | |
| American clam shrimp | Limnadia lenticularis | Species of Concern | Wherever found | |
| American Coot | Fulica americana americana | Species of Concern | | |
| American crocodile | Crocodylus acutus | Endangered | Wherever found, except in U.S.A. (FL) | 03-20-2007 |
| American crocodile | Crocodylus acutus | Threatened | U.S.A. (FL) | 10-28-1975 |
| American Dipper | Cinclus mexicanus | Species of Concern | | |
| American Dipper | Cinclus mexicanus unicolor | Resolved Taxon | Wherever found | |
| American dry rock moss | Grimmia americana | Resolved Taxon | Wherever found | |
| American eel | Anguilla rostrata | Resolved Taxon | Wherever found | |
| American Flamingo | Phoenicopterus ruber | Species of Concern | Wherever found | |
| American ginseng | Panax quinquefolius | Resolved Taxon | Wherever found | |
| American Golden-Plover | Pluvialis dominica | Species of Concern | | |
| American hart's-tongue fern | Asplenium scolopendrium var. americanum | Threatened | Wherever found | 07-14-1989 |
| American Kestrel | Falco sparverius paulus | Species of Concern | Wherever found | |
| American Marten | Martes americana | Not Listed | | |
| American Oystercatcher | Haematopus palliatus | Species of Concern | Wherever found | |
| American peregrine falcon | Falco peregrinus anatum | Recovery | Wherever found | 06-02-1970 |
| American pika | Ochotona princeps | Resolved Taxon | Wherever found | |
| American sandburrowing mayfly | Dolania americana | Species of Concern | Wherever found | |
| American shad | Alosa sapidissima | Species of Concern | | |
| American swallow-tailed kite | Elanoides forficatus forficatus | Resolved Taxon | Wherever found | |
| American White Pelican | pelecanus erythrorhynchos | Species of Concern | Wherever found | |
| A millipede | Polydesmus cavicola | Resolved Taxon | Wherever found | |
| Amistad gambusia | Gambusia amistadensis | Extinction | Wherever found | 04-30-1980 |
| Ammon's tortula | Tortula ammonsiana | Species of Concern | Wherever found | |
| Amphibious caddisfly | Desmona bethula | Species of Concern | Wherever found | |
| Ample elimia | Elimia ampla | Not Listed | Wherever found | |
| Amsterdam Albatross | Diomedia amsterdamensis | Endangered | Wherever found | 01-12-1995 |
| Amur Sturgeon | Acipenser schrenckii | Proposed Endangered | Wherever found | |
| Anacapa deer mouse | Peromyscus maniculatus anacapae | Resolved Taxon | Wherever found | |
| Anastasia Island beach mouse | Peromyscus polionotus phasma | Endangered | Wherever found | 05-12-1989 |
| Anastasia Island cotton mouse | Peromyscus gossypinus anastasae | Resolved Taxon | Wherever found | |
| Anastasia Island mole | Scalopus aquaticus anastasae | Resolved Taxon | Wherever found | |
| `Anaunau | Lepidium arbuscula | Endangered | Wherever found | 10-10-1996 |
| `Anaunau | Lepidium bidentatum o-waihiense | Resolved Taxon | Wherever found | |
| `Anaunau | Lepidium serra | Species of Concern | Wherever found | |
| Ana wingless thread bug | Nesidiolestes ana | Species of Concern | Wherever found | |
| Anchialine pool shrimp | Antecaridina lauensis | Resolved Taxon | Wherever found | |
| Anchialine pool shrimp | Metabetaeus lohena | Resolved Taxon | Wherever found | |
| Anchialine pool shrimp | Palaemonella burnsi | Resolved Taxon | Wherever found | |
| Anchialine pool shrimp | Vetericaris chaceorum | Endangered | Wherever found | 11-29-2013 |
| Anchialine pool Shrimp | Calliasmata pholidota | Resolved Taxon | Wherever found | |
| Anchialine pool Shrimp | Procaris hawaiana | Endangered | Wherever found | 10-31-2016 |
| Anchialine Pool Snail | Neritilia hawaiiensis | Species of Concern | Wherever found | |
| Ancient ant | Smithistruma reliquia | Species of Concern | Wherever found | |
| Ancient Murrelet | Synthliboramphus antiquus | Species of Concern | | |
| Andean cat | Felis jacobita | Endangered | Wherever found | 06-14-1976 |
| Andean condor | Vultur gryphus | Endangered | Wherever found | 12-02-1970 |
| Andean flamingo | Phoenicoparrus andinus | Endangered | Wherever found | 09-16-2010 |
| Anderson's brachymenium | Brachymenium andersonii | Species of Concern | Wherever found | |
| Anderson sedge | Carex micropoda | Resolved Taxon | Wherever found | |
| Andrenid bee | Perdita glamis | Resolved Taxon | Wherever found | |
| Andrenid Bee | Perdita algondones | Resolved Taxon | Wherever found | |
| Andrenoid yellow-faced bee | Hylaeus andrenoides | Species of Concern | Wherever found | |
| Andrews' dune scarab beetle | Pseudocotalpa andrewsi | Resolved Taxon | Wherever found | |
| Andrew's frigatebird | Fregata andrewsi | Endangered | Wherever found | 06-14-1976 |
| Andrew's marble butterfly | Euchloe hyantis andrewsi | Species of Concern | Wherever found | |
| Andros Island ground iguana | Cyclura cychlura cychlura | Threatened | Wherever found | 06-22-1983 |
| Anegada ground iguana | Cyclura pinguis | Endangered | Wherever found | 06-02-1970 |
| Angel shark | Squatina squatina | Endangered | | 08-31-2016 |
| Angled riffleshell | Epioblasma biemarginata | Resolved Taxon | Wherever found | |
| Angular Dwarf crayfish | Cambarellus lesliei | Under Review | Wherever found | |
| Angular pebblesnail | Somatogyrus biangulatus | Species of Concern | Wherever found | |
| Angulated tortoise | Geochelone yniphora | Endangered | Wherever found | 06-14-1976 |
| Anianiau | Magumma parva | Species of Concern | Wherever found | |
| Animas minute moss beetle | Limnebius aridus | Species of Concern | Wherever found | |
| animas mountains tubeshell | holospira animasensis | Resolved Taxon | Wherever found | |
| Animas Peak Woodlandsnail | Ashmunella animasensis | Resolved Taxon | Wherever found | |
| Animas southern pocket gopher | Thomomys umbrinus emotus | Resolved Taxon | Wherever found | |
| Animas Talussnail | Sonorella animasensis | Resolved Taxon | Wherever found | |
| Anjouan Island sparrowhawk | Accipiter francesii pusillus | Endangered | Wherever found | 06-02-1970 |
| Anjouan scops owl | Otus rutilus capnodes | Endangered | Wherever found | 06-02-1970 |
| Annectans rhopalid bug | Ithamar annectans | Species of Concern | Wherever found | |
| Annointed sallow noctuid moth | Pyreferra ceromatica | Species of Concern | Wherever found | |
| Anomalous spring amphipod | Crangonyx anomalus | Resolved Taxon | Wherever found | |
| Anomalous yellow-faced bee | Hylaeus anomala | Species of Concern | Wherever found | |
| A Notodontid moth | Crinodes mcfarlandi | Resolved Taxon | Wherever found | |
| A Notodontid moth | Heterocampa sp. 1 nr. amanda | Resolved Taxon | Wherever found | |
| A Notodontid moth | Litodonta sp. 1 nr. alpina | Resolved Taxon | Wherever found | |
| A Notodontid moth | ursia species | Status Undefined | Wherever found | |
| A Notodontid Moth | Heterocampa rufinans | Resolved Taxon | Wherever found | |
| Antelope Island pocket gopher | Thomomys umbrinus nesophilus | Species of Concern | Wherever found | |
| Anthony blister beetle | Lytta mirifica | Species of Concern | Wherever found | |
| Anthony Peak lupine | Lupinus antoninus | Species of Concern | Wherever found | |
| Anthony's riversnail | Athearnia anthonyi | Endangered | Wherever found; Except where listed as Experimental Populations | 04-15-1994 |
| Anthony's riversnail | Athearnia anthonyi | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Anthony's riversnail | Athearnia anthonyi | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Anthricinan yellow-faced bee | Hylaeus anthracinus | Endangered | Wherever found | 10-31-2016 |
| Antillean Manatee | Trichechus manatus manatus | Proposed Endangered | | |
| Antillean Mango | Anthracothorax dominicus | Species of Concern | Wherever found | |
| Antillean Mango | Anthracothorax dominicus aurulentus | Species of Concern | | |
| Antioch andrenid bee | Perdita scitula antiochensis | Species of Concern | Wherever found | |
| Antioch cophuran robberfly | Cophura hurdi | Species of Concern | Wherever found | |
| Antioch Dunes anthicid | Anthicus antiochensis | Species of Concern | Wherever found | |
| Antioch Dunes evening-primrose | Oenothera deltoides ssp. howellii | Endangered | Wherever found | 05-27-1978 |
| Antioch Dunes shieldback katydid | Neduba extincta | Resolved Taxon | Wherever found | |
| Antioch Dune weevil | Dysticheus rotundicollis | Resolved Taxon | Wherever found | |
| Antioch efferian robberfly | Efferia antiochi | Species of Concern | Wherever found | |
| Antioch mutillid wasp | Myrmosula pacifica | Species of Concern | Wherever found | |
| Antioch potter wasp | Microdynerus arenicolus | Resolved Taxon | Wherever found | |
| Antioch sphecid wasp | Philanthus nasalis | Species of Concern | Wherever found | |
| `Anunu | Sicyos albus | Endangered | Wherever found | 10-10-1996 |
| `Anunu | Sicyos cucumerinus | Species of Concern | Wherever found | |
| `Anunu | Sicyos macrophyllus | Endangered | Wherever found | 10-31-2016 |
| Anza Borrego blind harvestman | Sitalcina borregoensis | Resolved Taxon | Wherever found | |
| Apache Pass rubberweed | Hymenoxys ambigens var. floribunda | Resolved Taxon | Wherever found | |
| Apache silverspot butterfly | Speyeria nokomis apacheana | Resolved Taxon | Wherever found | |
| Apache Talussnail | Sonorella apache | Resolved Taxon | Wherever found | |
| Apache trout | Oncorhynchus apache | Recovery | Wherever found | 03-11-1967 |
| Apache wild-buckwheat | Eriogonum apachense | Species of Concern | Wherever found | |
| Apalachicola doll's daisy | Boltonia apalachicolensis | Species of Concern | Wherever found | |
| Apalachicola floater | Anodonta heardi | Status Undefined | Wherever found | |
| Apalachicola king snake | Lampropeltis getula meansi | Under Review | Wherever found | |
| Apalachicola rosemary | Conradina glabra | Endangered | | 07-12-1993 |
| Apalachicola twilight skimmer | Neurocordulia clara | Species of Concern | Wherever found | |
| Apalachicola wild indigo | Baptisia megacarpa | Resolved Taxon | | |
| 'Apapane | Himatione sanguinea | Species of Concern | Wherever found | |
| Apaporis River caiman | Caiman crocodilus apaporiensis | Endangered | Wherever found | 06-14-1976 |
| Apennine chamois | Rupicapra rupicapra ornata | Endangered | Wherever found | 06-14-1976 |
| Aphanisma | Aphanisma blitoides | Species of Concern | Wherever found | |
| Aphodius tortoise commensal scarab | Aphodius troglodytes | Species of Concern | Wherever found | |
| (Aphrastochthonius) pseudoscorpion | aphrastochthonius | Species of Concern | Wherever found | |
| Aplokating-palaoan | Psychotria malaspinae | Endangered | Wherever found | 11-02-2015 |
| Apoda | Pelea parvifolia apoda | Resolved Taxon | Wherever found | |
| Appalachian Adder's-mouth | Malaxis bayardii | Species of Concern | | |
| Appalachian Bewick's wren | Thryomanes bewickii altus | Species of Concern | Wherever found | |
| Appalachian Cave crayfish | Orconectes packardi | Status Undefined | Wherever found | |
| Appalachian cottontail rabbit | Sylvilagus obscurus | Status Undefined | Wherever found | |
| Appalachian dust bunnies | Lepraria lanata | Species of Concern | | |
| Appalachian elktoe | Alasmidonta raveneliana | Endangered | Wherever found | 11-23-1994 |
| Appalachian Fissidens moss | Fissidens appalachensis | Status Undefined | | |
| Appalachian monkeyface (pearlymussel) | Theliderma sparsa | Endangered | Wherever found | 06-14-1976 |
| Appalachian monkeyface (pearlymussel) | Theliderma sparsa | Experimental Population, Non-Essential | USA (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Appalachian snaketail | Ophiogomphus incurvatus | Status Undefined | Wherever found | |
| Appalachian Valley cave amphipod | Crangonyx antennatus | Resolved Taxon | Wherever found | |
| Applegate's milk-vetch | Astragalus applegatei | Endangered | Wherever found | 07-28-1993 |
| Applegate stonecrop | Sedum oblanceolatum | Species of Concern | Wherever found | |
| Aqua Dulce Talussnail | Sonorella meadi | Resolved Taxon | Wherever found | |
| Aquarius paintbrush | Castilleja aquariensis | Resolved Taxon | Wherever found | |
| Aquatic box turtle | Terrapene coahuila | Endangered | Wherever found | 06-04-1973 |
| Aquatic snail | valvata mergella | Species of Concern | Wherever found | |
| Arabian gazelle | Gazella gazella | Endangered | Wherever found | 07-27-1979 |
| Arabian oryx | Oryx leucoryx | Endangered | Wherever found | 06-02-1970 |
| Arabian ostrich | Struthio camelus syriacus | Endangered | Wherever found | 06-02-1970 |
| Arabian tahr | Hemitragus jayakari | Endangered | Wherever found | 07-27-1979 |
| Aransas short-tailed shrew | Blarina hylophaga plumbea | Species of Concern | Wherever found | |
| Arapahoe snowfly | Arsapnia arapahoe | Resolved Taxon | Wherever found | |
| Aravaipa sage | Salvia amissa | Species of Concern | Wherever found | |
| Arbuckle Cave ground beetle | Horologion speokites | Species of Concern | Wherever found | |
| Archbold anomalan scarab | Anomala eximia | Species of Concern | Wherever found | |
| Archer's toothed land snail | Fumonelix archeri | Resolved Taxon | Wherever found | |
| Arctic Char | Salvelinus alpinus | Not Listed | | |
| Arctic Cisco | Coregonus autumnalis | Not Listed | | |
| Arctic grayling | Thymallus arcticus | Not Listed | Wherever found | |
| Arctic grayling | Thymallus arcticus | Resolved Taxon | Upper Missouri River DPS | |
| Arctic Lamprey | Lethenteron camtschaticum | Not Listed | | |
| Arctic peregrine Falcon | Falco peregrinus tundrius | Recovery | Wherever found | 06-02-1970 |
| Arctic sage | Artemisia senjavinensis | Resolved Taxon | Wherever found | |
| Arctic Tern | Sterna paradisaea | Species of Concern | Wherever found | |
| Arctiidae arctia | Arctia speciesone | Under Review | Wherever found | |
| Arcuate bush mallow | malacothamnus arcuatus | Species of Concern | Wherever found | |
| Arduous eopenthes click beetle | Eopenthes arduus | Species of Concern | Wherever found | |
| Argali | Ovis ammon | Endangered | Wherever found except Kyrgyzstan, Mongolia, and Tajikistan | 06-14-1976 |
| Argali | Ovis ammon | Threatened | Kyrgyzstan, Mongolia, and Tajikistan | 06-23-1992 |
| Argentine angelshark | Squatina argentina | Endangered | | |
| Argo ephemerellan mayfly | Ephemerella argo | Species of Concern | Wherever found | |
| Argyle Canyon Phacelia | Phacelia argylensis | Resolved Taxon | Wherever found | |
| Arid northern clarkia | Clarkia borealis arida | Species of Concern | Wherever found | |
| Arizona agave | Agave arizonica | Original Data in Error - Not a listable entity | | 05-18-1984 |
| Arizona Bell's vireo | Vireo bellii arizonae | Resolved Taxon | Wherever found | |
| Arizona black-tailed prairie dog | Cynomys ludovicianus arizonensis | Species of Concern | Wherever found | |
| Arizona brome | Bromus arizonicus | Resolved Taxon | Wherever found | |
| Arizona bugbane | Cimicifuga arizonica | Resolved Taxon | Wherever found | |
| Arizona cave amphipod | Stygobromus arizonensis | Resolved Taxon | Wherever found | |
| Arizona Cliffrose | Purshia (=Cowania) subintegra | Endangered | Wherever found | 05-29-1984 |
| Arizona eryngo | Eryngium sparganophyllum | Endangered | | 03-04-2021 |
| Arizona giant sand treader cricket | Daihinibaenetes arizonensis | Species of Concern | Wherever found | |
| Arizona Gilbert's skink | Eumeces gilberti arizonensis | Species of Concern | Wherever found | |
| Arizona hedgehog cactus | Echinocereus arizonicus ssp. arizonicus | Endangered | Wherever found | 11-26-1979 |
| Arizona leatherflower | Clematis hirsutissima arizonica | Resolved Taxon | Wherever found | |
| Arizona Monkshood | Aconitum infectum | Resolved Taxon | Wherever found | |
| Arizona montane vole | Microtus montanus arizonensis | Resolved Taxon | Wherever found | |
| Arizona Myotis | Myotis occultus | Species of Concern | | |
| Arizona night lizard | Xantusia vigilis arizonae | Resolved Taxon | Wherever found | |
| Arizona prickle-poppy | Argemone arizonica | Resolved Taxon | Wherever found | |
| Arizona ridge-nosed rattlesnake | Crotalus willardi willardi | Resolved Taxon | Wherever found | |
| Arizona shrew | Sorex arizonae | Species of Concern | Wherever found | |
| Arizona star leaf | Choisya arizonica | Resolved Taxon | Wherever found | |
| Arizona striped whiptail | Aspidoscelis inornatus arizonae | Not Listed | Wherever found | |
| Arizona toad | Anaxyrus microscaphus | Under Review | Wherever found | |
| Arizona Treefrog | Hyla wrightorum | Resolved Taxon | Huachuca/Canelo Population | |
| Arizona water penny | Psephenus arizonensis | Species of Concern | Wherever found | |
| Arizona water shrew | Sorex palustris navigator | Resolved Taxon | Wherever found | |
| Arizona wetsalts Tiger Beetle | Cicindela haemorrhagica arizonae | Resolved Taxon | Wherever found | |
| Arizona willow | Salix arizonica | Resolved Taxon | Wherever found | |
| Arizona Woodpecker | Dryobates arizonae | Species of Concern | Wherever found | |
| Arizona yellow mud turtle | Kinosternon flavescens arizonense | Resolved Taxon | Wherever found | |
| Arkansas agapetus caddisfly | Agapetus medicus | Species of Concern | Wherever found | |
| Arkansas Broken-Ray | Lampsilis reeveiana | Not Listed | | |
| Arkansas darter | Etheostoma cragini | Resolved Taxon | Wherever found | |
| Arkansas fatmucket | Lampsilis powellii | Threatened | Wherever found | 04-05-1990 |
| Arkansas mudalia | Leptoxis arkansensis | Resolved Taxon | Wherever found | |
| Arkansas River feverfew | Parthenium tetraneuris | Species of Concern | Wherever found | |
| Arkansas River shiner | Notropis girardi | Threatened | Arkansas River Basin (AR, KS, NM, OK, TX) | 11-23-1998 |
| Arkansas Wedge | Triodopsis occidentalis | Species of Concern | Wherever found | |
| Armenian Whiskered Bat | Myotis hajastanicus | Under Review | Wherever found | |
| Armored rocksnail | Lithasia armigera | Species of Concern | Wherever found | |
| Armored snail | Marstonia pachyta | Endangered | Wherever found | 02-25-2000 |
| Aroostook sedge | Carex sterilis | Resolved Taxon | Wherever found | |
| Arrowleaf Falsepickerelweed | Monochoria hastata | Not Listed | | |
| Arroyo (=arroyo southwestern) toad | Anaxyrus californicus | Endangered | Wherever found | 12-16-1994 |
| Arroyo chub | Gila orcuttii | Species of Concern | Wherever found | |
| Arroyo de la Cruz manzanita | Arctostaphylos cruzensis | Species of Concern | Wherever found | |
| Arroyo de la Cruz mariposa lily | Calochortus clavatus recurvifolius | Species of Concern | Wherever found | |
| Arroyo Seco bush-mallow | Malacothamnus palmeri lucianus | Species of Concern | Wherever found | |
| Artesian agapetus caddisfly | Agapetus artesus | Species of Concern | Wherever found | |
| Aruba Island rattlesnake | Crotalus unicolor | Threatened | Wherever found | 06-22-1983 |
| Ash-breasted tit-tyrant | Anairetes alpinus | Endangered | Wherever found | 07-24-2012 |
| Ash Creek ivesia | Ivesia paniculata | Species of Concern | Wherever found | |
| Ashe's magnolia | Magnolia ashei | Species of Concern | Wherever found | |
| Ash-grey paintbrush | Castilleja cinerea | Threatened | Wherever found | 10-14-1998 |
| Ashland Lupine | Lupinus aridus ssp. ashlandensis | Resolved Taxon | Wherever found | |
| Ashland shrew | Sorex trigonirostris | Resolved Taxon | Wherever found | |
| Ashland thistle | Cirsium ciliolatum | Resolved Taxon | Wherever found | |
| Ash Meadows Amargosa pupfish | Cyprinodon nevadensis mionectes | Endangered | Wherever found | 05-10-1982 |
| Ash Meadows blazingstar | Mentzelia leucophylla | Threatened | Wherever found | 05-20-1985 |
| Ash Meadows gumplant | Grindelia fraxinipratensis | Threatened | Wherever found | 05-20-1985 |
| Ash Meadows ivesia | Ivesia kingii var. eremica | Threatened | Wherever found | 05-20-1985 |
| Ash Meadows ladies'-tresses | Spiranthes infernalis | Species of Concern | Wherever found | |
| Ash meadows milk-vetch | Astragalus phoenix | Threatened | Wherever found | 05-20-1985 |
| Ash Meadows montane vole | Microtus montanus nevadensis | Species of Concern | Wherever found | |
| Ash Meadows naucorid | Ambrysus amargosus | Threatened | Wherever found | 05-20-1985 |
| Ash Meadows pebblesnail | Pyrgulopsis erythropoma | Resolved Taxon | Wherever found | |
| Ash Meadows poolfish | Empetrichthys merriami | Resolved Taxon | Wherever found | |
| Ash Meadows speckled dace | Rhinichthys osculus nevadensis | Endangered | Wherever found | 05-10-1982 |
| Ash Meadows sunray | Enceliopsis nudicaulis var. corrugata | Threatened | Wherever found | 05-20-1985 |
| Ash penstemon | Penstemon cinicola | Resolved Taxon | Wherever found | |
| Ashy darter | Etheostoma cinereum | Resolved Taxon | Wherever found | |
| Ashy dogweed | Thymophylla tephroleuca | Endangered | Wherever found | 07-19-1984 |
| ashy pebblesnail | Fluminicola fuscus | Not Listed | | |
| Ashy phacelia | Phacelia distans | Species of Concern | Wherever found | |
| Ashy spike-moss | selaginella cinerascens | Species of Concern | Wherever found | |
| Ashy Storm-petrel | Hydrobates homochroa | Resolved Taxon | Wherever found | |
| Asian bonytongue | Scleropages formosus | Endangered | Wherever found | 06-14-1976 |
| Asian elephant | Elephas maximus | Endangered | Wherever found | 06-14-1976 |
| Asian golden (=Temmnick's) cat | Catopuma (=Felis) temminckii | Endangered | Wherever found | 06-14-1976 |
| Asian tapir | Tapirus indicus | Endangered | Wherever found | 06-14-1976 |
| Asian wild ass | Equus hemionus | Endangered | Wherever found | 06-02-1970 |
| A Spur-throat Grasshopper | Melanoplus magdalenae | Resolved Taxon | Wherever found | |
| Assimulans yellow-faced bee | Hylaeus assimulans | Endangered | Wherever found | 10-31-2016 |
| A stonefly | Capnia arapahoe | Resolved Taxon | Wherever found | |
| A stonefly | Sweltsa cristata | Resolved Taxon | Wherever found | |
| Atascodero june beetle | Polyphylla nubila | Species of Concern | Wherever found | |
| Athens long-horned caddisfly | Triaenodes phalacris | Resolved Taxon | Wherever found | |
| Atitlan grebe | Podilymbus gigas | Endangered | Wherever found | 06-02-1970 |
| Atlantic Croaker | Micropogonias undulatus | Not Listed | | |
| Atlantic humpback dolphin | Sousa teuszil | Endangered | | |
| Atlantic Menhaden | Brevoortia tyrannus | Not Listed | | |
| Atlantic pigtoe | Fusconaia masoni | Threatened | Wherever found | 12-16-2021 |
| Atlantic Puffin | Fratercula arctica | Species of Concern | Wherever found | |
| Atlantic salmon | Salmo salar | Endangered | Gulf of Maine DPS - See 50 CFR 224.101 | 06-19-2009 |
| Atlantic salmon | Salmo salar | Resolved Taxon | Kennebec River DPS | 06-19-2009 |
| Atlantic salmon | Salmo salar | Resolved Taxon | U.S.A. ME Gulf of Maine Atlantic Salmon Distinct Population Segment, which includes all naturally reproducing wild populations and those river-specific hatchery populations of Atlantic salmon having historical, river-specific characteristics found north of and including tributaries of the lower Kennebec River to, but not including, the mouth of the St. Croix River at the U.S.-Canda border. To date, the Services have determined that these populations are found in the Dennys, East Machias, Machias, Pleasant, Narraguagus, Sheepscot, and Ducktrap Rivers and in Cove Brook, Maine | 11-17-2000 |
| Atlantic salt marsh snake | Nerodia clarkii taeniata | Threatened | Wherever found | 12-29-1977 |
| Atlantic sturgeon | Acipenser oxyrinchus oxyrinchus | Endangered | Carolina DPS - See 50 CFR 224.101 | 02-06-2012 |
| Atlantic sturgeon | Acipenser oxyrinchus oxyrinchus | Endangered | Chesapeake Bay DPS - See 50 CFR 224.101 | 02-06-2012 |
| Atlantic sturgeon | Acipenser oxyrinchus oxyrinchus | Endangered | New York Bight DPS - See 50 CFR 224.101 | 02-06-2012 |
| Atlantic sturgeon | Acipenser oxyrinchus oxyrinchus | Endangered | South Atlantic DPS - See 50 CFR 224.101 | 02-06-2012 |
| Atlantic sturgeon | Acipenser oxyrinchus oxyrinchus | Threatened | Gulf of Maine DPS - See 50 CFR 223.102 | 02-06-2012 |
| Atlas pebblesnail | Somatogyrus humerosus | Species of Concern | Wherever found | |
| Atossa fritillary | Speyeria adiaste atossa | Resolved Taxon | Wherever found | |
| Attwater's greater prairie-chicken | Tympanuchus cupido attwateri | Endangered | Wherever found | 03-11-1967 |
| Atwood's catseye | Cryptantha atwoodii | Resolved Taxon | Wherever found | |
| Auburua Ranch jewelflower | Streptanthus insignis lyonii | Species of Concern | Wherever found | |
| Audouin's gull | Larus audouinii | Endangered | Wherever found | 06-02-1970 |
| Audubon's oriole | Icterus graduacauda audubonii | Species of Concern | Wherever found | |
| Audubon's Oriole | Icterus graduacauda | Species of Concern | Wherever found | |
| Audubon's Shearwater | Puffinus lherminieri | Species of Concern | Wherever found | |
| Aukland Island rail | Rallus pectoralis muelleri | Endangered | Wherever found | 06-02-1970 |
| Aupaka | Isodendrion hosakae | Endangered | Wherever found | 01-14-1991 |
| Aupaka | Isodendrion laurifolium | Endangered | Wherever found | 10-10-1996 |
| Aupaka | Isodendrion longifolium | Threatened | Wherever found | 10-10-1996 |
| Auricled twayblade | Listera auriculata | Resolved Taxon | Wherever found | |
| Auriculate false-foxglove | Agalinis auriculata | Species of Concern | Wherever found | |
| Austin blind Salamander | Eurycea waterlooensis | Endangered | Wherever found | 09-19-2013 |
| Austin's popcornflower | Plagiobothrys austiniae | Species of Concern | Wherever found | |
| Australasian Swamphen | Porphyrio melanotus samoensis | Species of Concern | | |
| Australian native mouse | Notomys aquilo | Endangered | Wherever found | 06-14-1976 |
| Australian native mouse | Zyzomys pedunculatus | Endangered | Wherever found | 06-14-1976 |
| Autumn Buttercup | Ranunculus aestivalis (=acriformis) | Endangered | Wherever found | 07-21-1989 |
| Avahi | Avahi laniger (entire genus) | Endangered | Wherever found | 06-02-1970 |
| Aven Nelson's phacelia | Phacelia anelsonii | Resolved Taxon | Wherever found | |
| Avon Park harebells | Crotalaria avonensis | Endangered | | 04-27-1993 |
| Awapa Daisy | Erigeron awapensis | Resolved Taxon | Wherever found | |
| `Awikiwiki | Canavalia molokaiensis | Endangered | Wherever found | 10-08-1992 |
| `Awikiwiki | Canavalia napaliensis | Endangered | Wherever found | 05-13-2010 |
| `Awikiwiki | Canavalia pubescens | Endangered | Wherever found | 06-27-2013 |
| Awiwi | Schenkia sebaeoides | Endangered | Wherever found | 10-29-1991 |
| 'Awiwi | Kadua cookiana | Endangered | Wherever found | 02-25-1994 |
| Awned bentgrass | Agrostis microphylla | Resolved Taxon | Wherever found | |
| Awned meadowbeauty | Rhexia aristosa | Species of Concern | Wherever found | |
| Aye-aye | Daubentonia madagascariensis | Endangered | Wherever found | 06-02-1970 |
| Ayumodoki (loach) | Hymenophysa curta | Endangered | Wherever found | 06-02-1970 |
| Azores wood pigeon | Columba palumbus azorica | Endangered | Wherever found | 06-02-1970 |
| Aztec gilia | Aliciella formosa | Under Review | Wherever found | |
| Babirusa | Babyrousa babyrussa | Endangered | Wherever found | 06-14-1976 |
| Bachman's Sparrow | Peucaea aestivalis | Species of Concern | Wherever found | |
| Bachman's warbler (=wood) | Vermivora bachmanii | Extinction | Wherever found | 03-11-1967 |
| Bactrian camel | Camelus bactrianus | Endangered | Wherever found | 06-14-1976 |
| Bactrian deer | Cervus elaphus bactrianus | Endangered | Wherever found | 07-27-1979 |
| Badlands wild-buckwheat | Eriogonum hylophilum | Resolved Taxon | Wherever found | |
| Badwater snail | Assiminea infima | Species of Concern | Wherever found | |
| Bahaman or Cuban parrot | Amazona leucocephala | Endangered | Wherever found | 06-02-1970 |
| Bahama swallowtail butterfly | Heraclides andraemon bonhotei | Original Data in Error - Act Amendment | Wherever found | 04-28-1976 |
| Bailey's ballmoss | Tillandsia baileyi | Species of Concern | Wherever found | |
| Baird's evening primrose | Camissonia bairdii | Resolved Taxon | Wherever found | |
| Baird's Sparrow | Centronyx bairdii | Resolved Taxon | Wherever found | |
| Bakersfield cactus | Opuntia treleasei | Endangered | Wherever found | 07-19-1990 |
| Bakersfield saltbush | Atriplex tularensis | Species of Concern | Wherever found | |
| Baker's larkspur | Delphinium bakeri | Endangered | Wherever found | 01-26-2000 |
| Baker's Llano pocket gopher | Geomys texensis bakeri | Species of Concern | Wherever found | |
| Baker's manzanita | Arctostaphylos bakeri bakeri | Resolved Taxon | Wherever found | |
| Baker's meadowfoam | Limnanthes bakeri | Species of Concern | Wherever found | |
| Baker's rhododendron | Rhododendron bakeri | Resolved Taxon | Wherever found | |
| Baker Station cave beetle | Pseudanophthalmus insularis | Resolved Taxon | Wherever found | |
| Baker's worm lizard | Amphisbaena bakeri | Resolved Taxon | Wherever found | |
| Baking Powder Flat blue | Euphilotes bernardino minuta | Resolved Taxon | Wherever found | |
| Balcones cave amphipod | Stygobromus balconis | Species of Concern | Wherever found | |
| Balcones Ghostsnail | Balconorbis uvaldensis | Resolved Taxon | Wherever found | |
| Balcones spike | Fusconaia iheringi | Endangered | | 07-05-2024 |
| Bald Cypress | Taxodium distichum | Not Listed | | |
| Bald Eagle | Haliaeetus leucocephalus | Recovery | U.S.A., conterminous (lower 48) States. | 03-11-1967 |
| Bald Eagle | Haliaeetus leucocephalus | Resolved Taxon | Sonoran Desert DPS: Arizona: (1) Yavapai, northern Mexico. Gila, Graham, Pinal, and Maricopa, Counties; and (2) Southern Mohave County (that portion south and east of the center of Interstate Highway 40 and east of Arizona Highway 95), eastern LaPaz County (that portion east of the centerline of U.S. and Arizona Highways 95), and north of the centerline of Interstate Highway 8). | 05-01-2008 |
| Bald Eagle | Haliaeetus leucocephalus | Resolved Taxon | Southwest Distinct Population Segment | |
| Bald grass | Sporobolus vaginiflorus var. ozarkanus | Resolved Taxon | Wherever found | |
| Baldwin Lake linanthus | Linanthus killipii | Species of Concern | Wherever found | |
| Ballhead, Thompson's waterleaf | Hydrophyllum capitatum thompsonii | Resolved Taxon | Wherever found | |
| Ballona cinquefoil | Potentilla multijuga | Species of Concern | Wherever found | |
| Balmorhea damselfly | Argia sp. | Species of Concern | Balmorhea | |
| Balmorhea saddle-case caddisfly | Protoptila balmorhea | Species of Concern | Wherever found | |
| Balsam Mountain Gentian | Gentiana latidens | Species of Concern | | |
| Balsam Mountain Hawthorn | Crataegus oreophila | Species of Concern | | |
| Baltimore Oriole | Icterus galbula | Species of Concern | Wherever found | |
| Baluchistan bear | Ursus thibetanus gedrosianus | Endangered | Wherever found | 05-16-1986 |
| Bananal tyrannulet | Serpophaga araguayae | Status Undefined | Wherever found | |
| Banbury Springs limpet | Idaholanx fresti | Endangered | Wherever found | 12-14-1992 |
| Banbury Springs Limpet | Lanx sp. | Not Listed | | |
| Banded bog skimmer | Williamsonia lintneri | Species of Concern | Wherever found | |
| Banded cotinga | Cotinga maculata | Endangered | Wherever found | 06-14-1976 |
| Banded Darter | Etheostoma zonale | Not Listed | | |
| Banded elimia | Elimia fascinans | Species of Concern | Wherever found | |
| Banded gila monster | Heloderma suspectum cinctum | Species of Concern | Wherever found | |
| Banded hare wallaby | Lagostrophus fasciatus | Endangered | Wherever found | 12-02-1970 |
| banded juga | Juga newberryi | Status Undefined | | |
| Banded Killifish | Fundulus diaphanus | Not Listed | | |
| Banded Sculpin | Cottus carolinae | Not Listed | | |
| Banded wattle-eye | Platysteira laticincta | Endangered | Wherever found | 01-12-1995 |
| bandfin darter | Etheostoma zonistium | Species of Concern | Wherever found | |
| Bandit Cave spider | Cicurina bandida | Resolved Taxon | Wherever found | |
| Band-rumped Storm-petrel | Hydrobates castro | Endangered | USA (HI) | 10-31-2016 |
| Band-rumped Storm-Petrel | Hydrobates castro | Species of Concern | | |
| Band-tailed pigeon | patagioenas fasciata | Species of Concern | Wherever found | |
| Banggai cardinalfish | Pterapogon kauderni | Threatened | | 02-19-2016 |
| Bankhead darter | Percina sipsi | Under Review | Wherever found | |
| Bank monkeyflower | Mimulus clivicola | Resolved Taxon | Wherever found | |
| Bank swallow | riparia riparia | Species of Concern | Wherever found | |
| Bannerman's turaco | Tauraco bannermani | Endangered | Wherever found | 01-12-1995 |
| Bantam Sunfish | Lepomis symmetricus | Not Listed | | |
| Banteng | Bos javanicus | Endangered | Wherever found | 06-02-1970 |
| Barbados yellow warbler (=wood) | Dendroica petechia petechia | Endangered | Wherever found | 06-02-1970 |
| Barbara Ann's tiger beetle | Cicindela politula barbarannae | Resolved Taxon | Wherever found | |
| Barbary deer | Cervus elaphus barbarus | Endangered | Wherever found | 07-27-1979 |
| Barbary hyena | Hyaena hyaena barbara | Endangered | Wherever found | 06-02-1970 |
| Barbary serval | Leptailurus (=Felis) serval constantina | Endangered | Wherever found | 06-02-1970 |
| Barbary stag | Cervus elaphus barbarus | Endangered | Wherever found | 06-02-1970 |
| Barbed rattlesnake root | Prenanthes barbata | Species of Concern | Wherever found | |
| Barberry-leaved hawthorn | Crataegus berberifolia | Resolved Taxon | Wherever found | |
| Barber's Point oliarus planthopper | Oliarus myoporicola | Species of Concern | Wherever found | |
| Barbour's map turtle | Graptemys barbouri | Similarity of Appearance (Threatened) | Wherever found | |
| Barefoot gecko | Coleonyx switaki | Species of Concern | Wherever found | |
| Barfoot Woodlandsnail | Ashmunella esuritor | Resolved Taxon | Wherever found | |
| Bariaco | Trichilia triacantha | Endangered | Wherever found | 02-05-1988 |
| Barneby catseye | Cryptantha barnebyi | Resolved Taxon | Wherever found | |
| Barneby milk-vetch | Astragalus barnebyi | Resolved Taxon | Wherever found | |
| Barneby reed-mustard | Schoenocrambe barnebyi | Endangered | Wherever found | 01-14-1992 |
| Barneby ridge-cress | Lepidium barnebyanum | Endangered | Wherever found | 09-28-1990 |
| Barnes' pika | Ochotona princeps barnesi | Species of Concern | Wherever found | |
| Barn Owl | Tyto alba | Species of Concern | Wherever found | |
| Barn Swallow | Hirundo rustica | Species of Concern | Wherever found | |
| Barratt's sedge | Carex barrattii | Resolved Taxon | Wherever found | |
| Barred bandicoot | Perameles bougainville | Endangered | Wherever found | 12-02-1970 |
| Barred Tiger Salamander | Ambystoma mavortium | Not Listed | | |
| Barred-wing rail | Rallus poecilopterus | Resolved Taxon | Wherever found | |
| Barrens bluet damselfly | Enallagma recurvatum | Resolved Taxon | Wherever found | |
| Barrens Dagger Moth | Acronicta albarufa | Species of Concern | Wherever found | |
| Barrens darter | Etheostoma forbesi | Resolved Taxon | Wherever found | |
| Barrens heelsplitter | Lasmigona sp. | Species of Concern | Wherever found | |
| Barrens sedge leafhopper | Limotettix sp. | Species of Concern | Wherever found | |
| Barrens topminnow | Fundulus julisia | Endangered | Wherever found | 11-20-2019 |
| Barrington land iguana | Conolophus pallidus | Endangered | Wherever found | 06-02-1970 |
| Barr's amphipod | Stygobromus cherylae | Not Listed | | |
| Barr's cave amphipod | Stygobromus barri | Species of Concern | Wherever found | |
| Barstow wooly-sunflower | Eriophyllum mohavense | Species of Concern | Wherever found | |
| Bar-tailed Godwit | Limosa lapponica | Species of Concern | Wherever found | |
| Bar-tailed pheasant | Syrmaticus humaie | Endangered | Wherever found | 06-02-1970 |
| Barton Cavesnail | Stygopyrgus bartonensis | Resolved Taxon | Wherever found | |
| Barton Flats horkelia | Horkelia wilderae | Species of Concern | Wherever found | |
| Barton Springs salamander | Eurycea sosorum | Endangered | Wherever found | 04-30-1997 |
| Bartram's hairstreak Butterfly | Strymon acis bartrami | Endangered | Wherever found | 09-11-2014 |
| Bartram's ixia | Calydorea coelestina | Resolved Taxon | Wherever found | |
| Bartram's stonecrop | Graptopetalum bartramii | Threatened | Wherever found | 09-29-2021 |
| Bartsch Holospira | Holospira yucatanensis | Resolved Taxon | Wherever found | |
| Basalt daisy | Erigeron basalticus | Resolved Taxon | Wherever found | |
| Basalt Juga | Juga sp | Resolved Taxon | Wherever found | |
| Basin bellflower | Campanula reverchonii | Resolved Taxon | Wherever found | |
| Bastrop Crayfish | Procambarus texanus | Resolved Taxon | Wherever found | |
| Bat Cave isopod | Caecidotea macropropoda | Species of Concern | Wherever found | |
| Bath County cave amphipod | Stygobromus mundus | Species of Concern | Wherever found | |
| Bat Ray | Myliobatis californica | Not Listed | | |
| Bay-breasted Warbler | Setophaga castanea | Species of Concern | Wherever found | |
| Bay checkerspot butterfly | Euphydryas editha bayensis | Threatened | Wherever found | 09-18-1987 |
| Bay matchweed | Gutierrezia californica | Resolved Taxon | Wherever found | |
| Bayou Bodcau crayfish | Bouchardina robisoni | Status Undefined | Wherever found | |
| Bayou darter | Etheostoma rubrum | Threatened | Wherever found | 10-28-1975 |
| Bay skipper | Euphyes bayensis | Resolved Taxon | Wherever found | |
| Bay Springs salamander | Plethodon ainsworthi | Resolved Taxon | Wherever found | |
| Beach, Grave's plum | Prunus maritima gravesii | Resolved Taxon | Wherever found | |
| Beach jacquemontia | Jacquemontia reclinata | Endangered | | 11-24-1993 |
| Beach layia | Layia carnosa | Threatened | Wherever found | 06-22-1992 |
| Beach spectacle-pod | Dithyrea maritima | Resolved Taxon | Wherever found | |
| Beach, Virginian pinweed | Lechea maritima virginica | Resolved Taxon | Wherever found | |
| Beach vole | Microtus breweri | Species of Concern | Wherever found | |
| Beaked Cavesnail | Phreatodrobia rotunda | Resolved Taxon | Wherever found | |
| Beaked clarkia | Clarkia rostrata | Species of Concern | Wherever found | |
| Beaked tracyina | Tracyina rostrata | Resolved Taxon | Wherever found | |
| Bearded Mountainsnail | Oreohelix barbata | Resolved Taxon | Wherever found | |
| Bearded popcornflower | Plagiobothrys hystriculus | Resolved Taxon | Wherever found | |
| Bearded red crayfish | Procambarus pogum | Resolved Taxon | Wherever found | |
| bearded Seal | Erignathus barbatus nauticus | Threatened | Beringia DPS - See 50 CFR 223.102 | 02-26-2013 |
| bearded Seal | Erignathus barbatus nauticus | Threatened | Okhotsk DPS - See 50 CFR 223.102 | 02-26-2013 |
| beardless chinchweed | Pectis imberbis | Endangered | Wherever found | 07-15-2021 |
| Bear gum | Nyssa ursina | Status Undefined | | |
| Bear Lake Sculpin | Cottus extensus | Resolved Taxon | Wherever found | |
| Bear Lake Whitefish | Prosopium abyssicola | Resolved Taxon | Wherever found | |
| Bearmouth mountainsnail | Oreohelix spthree | Resolved Taxon | Wherever found | |
| Bear Valley milk-vetch | Astragalus lentiginosus ursinus | Resolved Taxon | Wherever found | |
| Bear Valley phlox | Phlox dolichantha | Species of Concern | Wherever found | |
| Bear Valley pyrrocoma | Pyrrocoma uniflora gossypina | Species of Concern | Wherever found | |
| Bear Valley sandwort | Arenaria ursina | Threatened | Wherever found | 10-14-1998 |
| Bear Valley wooly-pod | Astragalus leucolobus | Species of Concern | Wherever found | |
| Beath milk-vetch | Astragalus beathii | Resolved Taxon | Wherever found | |
| Beatley buckwheat | Eriogonum beatleyae | Resolved Taxon | Wherever found | |
| Beatley milk-vetch | Astragalus beatleyae | Resolved Taxon | Wherever found | |
| Beatley phacelia | Phacelia beatleyae | Species of Concern | Wherever found | |
| Beatley's clover | Trifolium andersonii beatleyae | Resolved Taxon | Wherever found | |
| Beautiful crayfish | Cambarus speciosus | Status Undefined | Wherever found | |
| Beautiful goetzea | Goetzea elegans | Endangered | Wherever found | 04-19-1985 |
| Beautiful Hulsea | Hulsea vestita ssp. callicarpha | Species of Concern | Wherever found | |
| Beautiful Parachute Spider | Poecilotheria formosa | Under Review | Wherever found | |
| Beautiful pawpaw | Deeringothamnus pulchellus | Endangered | | 09-26-1986 |
| Beautiful shiner | Cyprinella formosa | Threatened | Wherever found | 08-31-1984 |
| Beaver Cave beetle | Pseudanophthalmus major | Resolved Taxon | Wherever found | |
| Beaver (Mongolian) | Castor fiber birulai | Endangered | Wherever found | 06-14-1976 |
| Beaver Mountain Groundsel | Packera castoreus | Resolved Taxon | Wherever found | |
| Beaver pond marstonia | Pyrgulopsis castor | Species of Concern | Wherever found | |
| Beaverpond marstonia | Marstonia castor | Resolved Taxon | Wherever found | |
| Beck's petrel | Pseudobulweria becki | Status Undefined | Wherever found | |
| Bee Creek Cave harvestman | Texella reddelli | Endangered | Wherever found | 09-16-1988 |
| Beegum onion | Allium hoffmanii | Resolved Taxon | Wherever found | |
| Beer's false water penny | Acneus beeri | Species of Concern | Wherever found | |
| Beetle | Cyclocephala wandae | Resolved Taxon | Wherever found | |
| Behren's silverspot butterfly | Speyeria zerene behrensii | Endangered | Wherever found | 12-05-1997 |
| Belding's orange-throated whiptail | cnemidophorus hyperythrus ssp. beldingi | Species of Concern | Wherever found | |
| Belding's Savannah Sparrow | Passerculus sandwichensis beldingi | Species of Concern | Wherever found | |
| Belfragi's chlorochroan bug | Chlorochroa belfragii | Species of Concern | Wherever found | |
| Belkin's dune tabanid fly | Brennania belkini | Resolved Taxon | Wherever found | |
| Beller's ground beetle | Agonum belleri | Species of Concern | Wherever found | |
| Bellinger's meadowfoam | Limnanthes floccosa bellingeriana | Species of Concern | Wherever found | |
| Bell's sage sparrow | Amphispiza belli belli | Species of Concern | Wherever found | |
| Bells Sparrow | Artemisiospiza belli | Species of Concern | Wherever found | |
| Bell's Twinpod | Physaria bellii | Species of Concern | Wherever found | |
| Bell's Vireo | Vireo bellii | Species of Concern | Wherever found | |
| belted crayfish | Faxonius harrisonii | Not Listed | | |
| Belted Kingfisher | Megaceryle alcyon | Species of Concern | Wherever found | |
| Beluga sturgeon | Huso huso | Threatened | Wherever found | 04-21-2004 |
| beluga whale | Delphinapterus leucas | Endangered | Cook Inlet DPS See 50 CFR 224.101 | 04-13-2011 |
| (Bembidion gordoni) ground beetle | bembidion gordoni | Species of Concern | Wherever found | |
| (Bembidion stillaguamish) ground beetle | bembidion stillaguamish | Species of Concern | Wherever found | |
| (Bembidion viator) ground beetle | bembidion viator | Species of Concern | Wherever found | |
| Benderman's cave beetle | Pseudanophthalmus bendermani | Species of Concern | Wherever found | |
| Bendire's Thrasher | Toxostoma bendirei | Species of Concern | Wherever found | |
| Ben Franklin's Beardtongue | Penstemon franklinii | Resolved Taxon | Wherever found | |
| Ben Lomond spineflower | Chorizanthe pungens var. hartwegiana | Endangered | Wherever found | 02-04-1994 |
| Ben Lomond wallflower | Erysimum teretifolium | Endangered | Wherever found | 02-04-1994 |
| Bennets Mill Cave water slater | Caecidotea carolinensis | Species of Concern | Wherever found | |
| Bensoniella | Bensoniella oregona | Species of Concern | Wherever found | |
| Bent avens | Geum geniculatum | Species of Concern | Wherever found | |
| Benton County cave crayfish | Cambarus aculabrum | Endangered | Wherever found | 04-27-1993 |
| Benton Valley speckled dace | Rhinichthys osculus ssp. | Species of Concern | Benton Valley | |
| Berenghenas halomtano | Solanum guamense | Endangered | Wherever found | 11-02-2015 |
| Bering Cisco | Coregonus laurettae | Not Listed | | |
| Berkeley Ground cricket | Neonemobius eurynotus | Resolved Taxon | Wherever found | |
| Berkeley kangaroo rat | Dipodomys heermanni berkleyensis | Species of Concern | Wherever found | |
| Bermuda petrel | Pterodroma cahow | Endangered | Wherever found | 06-02-1970 |
| Berner's two-winged mayfly | Heterocleon berneri | Species of Concern | Wherever found | |
| Berry Cave salamander | Gyrinophilus gulolineatus | Resolved Taxon | Wherever found | |
| Berry's mountainsnail | Oreohelix strigosa berryi | Species of Concern | Wherever found | |
| Bethany Beach firefly | Photuris bethaniensis | Proposed Threatened | | |
| Bezy's night lizard | Xantusia bezyi | Resolved Taxon | Wherever found | |
| Bicknell's thrush | Catharus bicknelli | Resolved Taxon | Wherever found | |
| Bicolored cactus snail | Xerarionta tryoni | Resolved Taxon | Wherever found | |
| Biddle's lupine | Lupinus oreganus var. oreganus | Species of Concern | Wherever found | |
| Bidecoratus sphecid wasp | Ectemnius bidecoratus | Species of Concern | Wherever found | |
| Bidens long-horned beetle | Plagithmysus bidensae | Species of Concern | Wherever found | |
| Bidwell's knotweed | Polygonum bidwelliae | Resolved Taxon | Wherever found | |
| Bifid duct pyrg | Pyrgulopsis peculiaris | Resolved Taxon | Wherever found | |
| Bifurcated cave amphipod | Stygobromus bifurcatus | Species of Concern | Wherever found | |
| Big Bar hesperian | Vespericola pressleyi | Under Review | Wherever found | |
| Big Bear milk-vetch | Astragalus lentiginosus sierrae | Species of Concern | Wherever found | |
| Big Bend bluegrass | Poa strictiramea | Resolved Taxon | Wherever found | |
| Big Bend gambusia | Gambusia gaigei | Endangered | Wherever found | 03-11-1967 |
| Big Bend hop hornbeam | Ostrya chisosensis | Species of Concern | Wherever found | |
| Big Bend mud turtle | Kinosternon hirtipes murrayi | Species of Concern | Wherever found | |
| Big Bend prickly pear | Grusonia densispina | Not Listed | | |
| Big Bend slider | Pseudemys scripta gaigeae | Resolved Taxon | Wherever found | |
| Big Black Rocksnail | Lithasia hubrichti | Not Listed | | |
| Big Blue Springs Cave crayfish | Procambarus horsti | Resolved Taxon | Wherever found | |
| Big Bluestem | Andropogon gerardii | Not Listed | | |
| Big brown bat | eptesicus fuscus | Species of Concern | Wherever found | |
| Big Cedar grasshopper | Eximacris phenax | Species of Concern | Wherever found | |
| Bigcheek Cave crayfish | Procambarus delicatus | Under Review | Wherever found | |
| Big Creek Crayfish | Faxonius peruncus | Threatened | | 05-30-2023 |
| Big cypress epidendrum | Epidendrum strobiliferum | Resolved Taxon | Wherever found | |
| Big Cypress fox squirrel | Sciurus niger avicennia | Resolved Taxon | Wherever found | |
| Big Dune aphodius scarab | Aphodius sp. | Species of Concern | Big Dune | |
| Big-eared kangaroo rat | Dipodomys elephantinus | Resolved Taxon | Wherever found | |
| Bigelow tansyaster | Dieteria bigelovii var. mucronata | Resolved Taxon | Wherever found | |
| Bigeye Chub | Hybopsis amblops | Not Listed | | |
| Bigeye Shiner | Notropis boops | Not Listed | | |
| Big free-tailed bat | Nyctinomops macrotis | Species of Concern | Wherever found | |
| Bigger's amphipod | Stygobromus biggersi | Species of Concern | Wherever found | |
| Bigger's groundwater planarian | Sphalloplana subtilis | Resolved Taxon | Wherever found | |
| big hatchet woodlandsnail | Ashmunella mearnsii | Resolved Taxon | Wherever found | |
| Bighorn sheep | Ovis canadensis | Species of Concern | Wherever found | |
| Bigleaf scurf-pea | Orbexilum macrophyllum | Species of Concern | Wherever found | |
| Big-leaved crownbeard | Verbesina dissita | Threatened | Wherever found | 10-07-1996 |
| Bigmouth Buffalo | Ictiobus cyprinellus | Not Listed | | |
| Bigmouth rocksnail | Leptoxis occultata | Resolved Taxon | Wherever found | |
| Bigmouth Shiner | Hybopsis dorsalis | Not Listed | | |
| Bigmouth Sleeper | Gobiomorus dormitor | Not Listed | | |
| Big Pine Key ataenius dung beetle | Ataenius superficialis | Species of Concern | Wherever found | |
| Big Pine Key conehead katydid | Belocephalus micanopy | Species of Concern | Wherever found | |
| Big Pine lomatium | Lomatium rigidum | Resolved Taxon | Wherever found | |
| Big Pine partridge pea | Chamaecrista lineata keyensis | Endangered | | 10-31-2016 |
| Bigpod bonamia | Bonamia ovalifolia | Resolved Taxon | Wherever found | |
| Big red sage | Salvia pentstemonoides | Proposed Endangered | Wherever found | |
| Big Sandy crayfish | Cambarus callainus | Threatened | Wherever found | 05-09-2016 |
| Big scale balsamroot | balsamorhiza macrolepis var. macrolepis | Species of Concern | Wherever found | |
| Bigscale Logperch | Percina macrolepida | Not Listed | | |
| Big Smoky Valley tui chub | Siphateles bicolor ssp. 8 | Species of Concern | Big Smoky | |
| Big South Fork crayfish | Cambarus bouchardi | Status Undefined | Wherever found | |
| Big Springs isopod | Bowmanasellus sequoiae | Status Undefined | | |
| Big Spring spinedace | Lepidomeda mollispinis pratensis | Threatened | Wherever found | 03-28-1985 |
| Big Thicket hog-nosed skunk | Conepatus mesoleucus telmalestes | Species of Concern | Wherever found | |
| Big-tooth covert snail | Fumonelix jonesiana | Resolved Taxon | Wherever found | |
| Big Warm Spring pyrg | Pyrgulopsis papillata | Resolved Taxon | Wherever found | |
| Bilobed rhyacophilan caddisfly | Rhyacophila mosana | Species of Concern | Wherever found | |
| Biltmore sedge | Carex biltmoreana | Resolved Taxon | Wherever found | |
| Bird's-eye primrose | Primula mistassinica | Resolved Taxon | Wherever found | |
| Birdwing pearlymussel | Lemiox rimosus | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Birdwing pearlymussel | Lemiox rimosus | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Birdwing pearlymussel | Lemiox rimosus | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Bishop Cap Tubesnail | Coelostemma pyrgonasta | Resolved Taxon | Wherever found | |
| Bishop's `o`o | Moho bishopi | Species of Concern | Wherever found | |
| Bisti Fleabane | Erigeron bistiensis | Not Listed | | |
| Bitterroot Mountainsnail | Oreohelix amariradix | Resolved Taxon | Wherever found | |
| Black Abalone | Haliotis cracherodii | Endangered | Wherever found | 04-13-2011 |
| Black-backed tanager | Tangara peruviana | Candidate | Wherever found | |
| Black-backed woodpecker | picoides arcticus | Resolved Taxon | Wherever found | |
| Black-Banded Sunfish | Enneacanthus chaetodon | Not Listed | | |
| Black barbthroat | Threnetes grzimeki | Resolved Taxon | Wherever found | |
| Blackbarred crayfish | Cambarus unestami | Not Listed | Wherever found | |
| Blackbeard Island white-tailed deer | Odocoileus virginianus nigribarbis | Species of Concern | Wherever found | |
| Black-bellied slender salamander | batrachoseps nigriventris | Species of Concern | Wherever found | |
| Black-billed Cuckoo | Coccyzus erythropthalmus | Species of Concern | Wherever found | |
| Black billed Magpie | Pica hudsonia | Species of Concern | Wherever found | |
| Blackbract pipewort | Eriocaulon nigrobracteatum | Under Review | | |
| black-breasted puffleg | Eriocnemis nigrivestis | Endangered | Wherever found | 08-26-2010 |
| Black Buffalo | Ictiobus niger | Not Listed | | |
| Black Bullhead | Ameiurus melas | Not Listed | | |
| Blackburn's pentarthrum weevil | Pentarthrum blackburni | Species of Concern | Wherever found | |
| Blackburn's rhyncogonus weevil | Rhyncogonus blackburni | Species of Concern | Wherever found | |
| Blackburn's sphinx moth | Manduca blackburni | Endangered | Wherever found | 02-01-2000 |
| Blackburn's yellow-faced bee | Hylaeus blackburni | Resolved Taxon | Wherever found | |
| Black caiman | Melanosuchus niger | Endangered | Wherever found | 06-14-1976 |
| Black Canyon Pyrg | Pyrgulopsis plicata | Resolved Taxon | Wherever found | |
| Black-capped Chickadee | Poecile atricapillus | Species of Concern | Wherever found | |
| Black-capped Chickadee | Poecile atricapillus practicus | Species of Concern | | |
| Black-capped Petrel | Pterodroma hasitata | Endangered | Wherever found | 01-29-2024 |
| Black-capped Vireo | Vireo atricapilla | Recovery | Wherever found | 10-06-1987 |
| Blackchin guitarfish | Rhinobatos cemiculus | Threatened | | |
| Black-chinned Sparrow | Spizella atrogularis | Species of Concern | Wherever found | |
| Blackchin Shiner | Notropis heterodon | Not Listed | | |
| Black clubshell | Pleurobema curtum | Endangered | Wherever found | 04-07-1987 |
| Black colobus monkey | Colobus satanas | Endangered | Wherever found | 10-19-1976 |
| Black Crappie | Pomoxis nigromaculatus | Not Listed | | |
| Black Creek crayfish | Procambarus pictus | Proposed Endangered | Wherever found | |
| Black-crest elima | Elimia albanyensis | Species of Concern | Wherever found | |
| Black-crowned Night-Heron | Nycticorax nycticorax | Species of Concern | Wherever found | |
| Black Drum | Pogonias cromis | Not Listed | | |
| Black-faced impala | Aepyceros melampus petersi | Endangered | Wherever found | 06-02-1970 |
| Blackfin cisco | Coregonus nigripinnis nigripinnis | Resolved Taxon | Wherever found | |
| Blackfin sucker | Thoburnia atripinnis | Resolved Taxon | Wherever found | |
| Black-flowered figwort | Scrophularia atrata | Species of Concern | Wherever found | |
| Black-footed Albatross | Phoebastria nigripes | Resolved Taxon | Wherever found | |
| Black-footed cat | Felis nigripes | Endangered | Wherever found | 06-14-1976 |
| Black-footed ferret | Mustela nigripes | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Black-footed ferret | Mustela nigripes | Experimental Population, Non-Essential | [Conata Basin/Badlands Reintroduction Area NEP] - U.S.A. (parts of SD) | 08-18-1994 |
| Black-footed ferret | Mustela nigripes | Experimental Population, Non-Essential | [Northcentral Montana Reintroduction Area NEP] - U.S.A. (parts of MT) | 08-18-1994 |
| Black-footed ferret | Mustela nigripes | Experimental Population, Non-Essential | [Shirley Basin/Medicine Bow Management Area NEP] - U.S.A. (parts of WY) | 08-21-1991 |
| Black-footed ferret | Mustela nigripes | Experimental Population, Non-Essential | U.S.A. (WY and specified portions of AZ, CO, MT, SD, and UT, see 17.84(g)(9)) | 08-21-1991 |
| Black-fronted piping-guan | Pipile jacutinga | Endangered | Wherever found | 06-14-1976 |
| Black Guillemot | Cepphus grylle | Species of Concern | Wherever found | |
| Black Hills redbelly snake | Storeria occipitomaculata pahasapae | Species of Concern | Wherever found | |
| Black hooded (black-headed) antwren | Formicivora erythronotos | Endangered | Wherever found | 01-27-2011 |
| Black howler monkey | Alouatta pigra | Threatened | Wherever found | 10-19-1976 |
| Black-knobbed map turtle | Graptemys nigrinoda | Under Review | Wherever found | |
| Black lace cactus | Echinocereus reichenbachii var. albertii | Endangered | Wherever found | 11-28-1979 |
| Black-legged Kittiwake | Rissa tridactyla | Species of Concern | Wherever found | |
| Black legless lizard | Anniella pulchra nigra | Resolved Taxon | Wherever found | |
| Blackline Hawaiian damselfly | Megalagrion nigrohamatum nigrolineatum | Endangered | Wherever found | 10-18-2012 |
| Black lordithon rove beetle | Lordithon niger | Species of Concern | Wherever found | |
| Black Mesa Talussnail | Sonorella russelli | Resolved Taxon | Wherever found | |
| Black Mountain cactus mouse | Peromyscus eremicus pullus | Species of Concern | Wherever found | |
| Black Mountain pocket mouse | Perognathus intermedius nigrimontis | Species of Concern | Wherever found | |
| Black Mountain Talussnail | Sonorella papagorum | Resolved Taxon | Wherever found | |
| Blackmouth shiner | Notropis melanostomus | Species of Concern | Wherever found | |
| Black mudalia | Elimia melanoides | Under Review | Wherever found | |
| Black mudalia | Leptoxis melanoides | Species of Concern | Wherever found | |
| Black-necked Crane | Grus nigricollis | Endangered | Wherever found | 06-14-1976 |
| Black Noddy | Anous minutus melanogenys | Species of Concern | | |
| Blacknose Dace | Rhinichthys atratulus | Not Listed | | |
| Blacknose Shiner | Notropis heterolepis | Not Listed | | |
| Black Oystercatcher | Haematopus bachmani | Species of Concern | Wherever found | |
| Black pinesnake | Pituophis melanoleucus lodingi | Threatened | Wherever found | 11-05-2015 |
| Black Rail | Laterallus jamaicensis | Species of Concern | Wherever found | |
| Black redhorse | Moxostoma duquesnii | Status Undefined | Wherever found | |
| Black rhinoceros | Diceros bicornis | Endangered | Sub-Saharan Africa | 07-14-1980 |
| Black rhyncogonus weevil | Rhyncogonus stygius | Species of Concern | Wherever found | |
| Black Rock Ground-daisy | Townsendia smithii | Resolved Taxon | Wherever found | |
| Black Rosy-Finch | Leucosticte atrata | Species of Concern | Wherever found | |
| Black Salamander | Aneides flavipunctatus | Not Listed | | |
| Black Sandshell | Ligumia recta | Not Listed | | |
| Black Scoter | Melanitta nigra | Species of Concern | Wherever found | |
| Black Sea Bass | Centropristis striata | Not Listed | | |
| Blackside dace | Phoxinus cumberlandensis | Threatened | Wherever found | 06-12-1987 |
| Blackside darter | Percina maculata | Status Undefined | Wherever found | |
| Black Skimmer | Rynchops niger | Species of Concern | Wherever found | |
| Black Skipjack | Euthynnus lineatus | Not Listed | | |
| Black softshell turtle | Trionyx nigricans | Endangered | Wherever found | 06-14-1976 |
| Black spored quillwort | Isoetes melanospora | Endangered | Wherever found | 02-05-1988 |
| Black-spotted newt | Notophthalmus meridionalis | Under Review | Wherever found | |
| Black Stilt | Himantopus novaezelandiae | Endangered | Wherever found | 01-16-2008 |
| Black Storm-Petrel | Hydrobates melania | Species of Concern | | |
| Blackstripe Topminnow | Fundulus notatus | Not Listed | | |
| Black Swift | Cypseloides niger | Species of Concern | Wherever found | |
| Black-tailed gnatcatcher | Polioptila melanura californica | Status Undefined | Wherever found | |
| Black-tailed prairie dog | Cynomys ludovicianus | Resolved Taxon | Wherever found | |
| Blacktail Redhorse | Moxostoma poecilurum | Not Listed | | |
| Blacktail Shiner | Cyprinella venusta | Not Listed | | |
| Black Tern | Chlidonias niger surinamenisis | Species of Concern | Wherever found | |
| Black-throated Gray Warbler | Setophaga nigrescens | Species of Concern | Wherever found | |
| Black-throated Green Warbler | Dendroica virens | Species of Concern | Wherever found | |
| Black-throated Green Warbler | Dendroica virens waynei | Species of Concern | | |
| Black throated Sparrow | Amphispiza bilineata | Species of Concern | Wherever found | |
| Black-throated Sparrow | Amphispiza bilineata bilineata | Species of Concern | | |
| Black-throated Sparrow | Amphispiza bilineata deserticola | Species of Concern | | |
| Black-throated Sparrow | Amphispiza bilineata opuntia | Species of Concern | | |
| Black toad | Bufo exsul | Species of Concern | Wherever found | 03-11-1967 |
| Black Toad | Anaxyrus exsul | Not Listed | | |
| Black Turnstone | Arenaria melanocephala | Species of Concern | | |
| Black-veined agrotis noctuid moth | Agrotis melanoneura | Species of Concern | Wherever found | |
| Black-vented Shearwater | Puffinus opisthomelas | Species of Concern | Wherever found | |
| Black warrior (=Sipsey Fork) Waterdog | Necturus alabamensis | Endangered | Wherever found | 02-02-2018 |
| Blackwater sandfiltering mayfly | Homoeoneuria dolani | Species of Concern | Wherever found | |
| Black-whiskered Vireo | Vireo altiloquus | Species of Concern | Wherever found | |
| Black-winged kite | Elanus caeruleus | Species of Concern | Wherever found | |
| Black-winged odynerus vespid wasp | Odynerus nigripennis | Species of Concern | Wherever found | |
| Black wooly-pod | Astragalus funereus | Species of Concern | Wherever found | |
| Bladen buttercup | Ranunculus laxicaulis | Resolved Taxon | Wherever found | |
| Blaine's fishhook cactus | Sclerocactus blainei | Resolved Taxon | Wherever found | |
| Blair's munzothamnus | Stephanomeria blairii | Species of Concern | Wherever found | |
| Blaisdell trigonoscuta weevil | Trigonoscuta blaisdelli | Species of Concern | Wherever found | |
| Blakley's spineflower | Chorizanthe blakleyi | Resolved Taxon | Wherever found | |
| Blanchard's Cricket Frog | Acris blanchardi | Not Listed | | |
| Blanchards' sphinx moth | Adhemarius blanchardorum | Resolved Taxon | Wherever found | |
| Blanco blind salamander | Eurycea robusta | Resolved Taxon | Wherever found | |
| Blanding's turtle | Emydoidea blandingii | Under Review | Wherever found | |
| Blarina carolinensis ssp. shermani | Blarina brevicauda shermani | Under Review | Wherever found | |
| Blasdale's bentgrass | Agrostis blasdalei blasdalei | Species of Concern | Wherever found | |
| bleached sandhill skipper | Polites sabuleti sinemaculata | Proposed Endangered | Wherever found | |
| Bleedingtooth Mussel | Venustaconcha pleasii | Not Listed | | |
| Bleufer | Potamilus purpuratus | Not Listed | | |
| Blind cave leiodid | Glacicavicola bathysciodes | Species of Concern | Wherever found | |
| Blind glyph | Glyphyalinia pecki | Species of Concern | Wherever found | |
| Blinn's Amphipod | Stygobromus blinni | Resolved Taxon | Wherever found | |
| Bliss Rapids snail | Taylorconcha serpenticola | Threatened | Wherever found | 12-14-1992 |
| Bloater | Coregonus hoyi | Not Listed | | |
| Block Island meadow vole | Microtus pennsylvanicus provectus | Species of Concern | Wherever found | |
| Blockman's leafy-daisy | Erigeron foliosus blochmaniae | Resolved Taxon | Wherever found | |
| Blodgett's sage | Salvia micrantha var. blodgettii | Resolved Taxon | Wherever found | |
| Blodgett's silverbush | Argythamnia blodgettii | Threatened | | 10-31-2016 |
| Blood River crayfish | Orconectes burri | Resolved Taxon | Wherever found | |
| Blotched gambusia | Gambusia senilis | Species of Concern | Wherever found | |
| Blotchside Logperch | Percina burtoni | Species of Concern | Wherever found | |
| Blowing cave beetle | Pseudanophthalmus ventus | Species of Concern | Wherever found | |
| Blowout penstemon | Penstemon haydenii | Endangered | Wherever found | 09-01-1987 |
| Blueback herring | Alosa aestivalis | Status Undefined | Wherever found | |
| Bluebarred pygmy sunfish | Elassoma okatie | Resolved Taxon | Wherever found | |
| Blue-billed curassow | Crax alberti | Endangered | Wherever found | 11-29-2013 |
| Blueblack silverspot butterfly | Speyeria nokomis nigrocaerulea | Resolved Taxon | Wherever found | |
| Bluebreast Darter | Nothonotus camurus | Not Listed | | |
| Blue Calamintha Bee | Osmia calaminthae | Under Review | Wherever found | |
| Blue Catfish | Ictalurus furcatus | Not Listed | | |
| Blue Chub | Gila coerulea | Not Listed | | |
| Blue Crab | Callinectes sapidus | Not Listed | | |
| Blue Diamond cholla | Opuntia X multigeniculata | Resolved Taxon | Wherever found | |
| Bluefin Trevally, Omilu | Caranx melampygus | Not Listed | | |
| Bluefish | Pomatomus saltatrix | Not Listed | | |
| Bluegill | Lepomis macrochirus | Not Listed | | |
| Blue glyphodes moth | Glyphodes cyanomichla | Species of Concern | Wherever found | |
| Blue gray Gnatcatcher | Polioptila caerulea | Species of Concern | Wherever found | |
| Blue-gray Noddy | Anous ceruleas | Species of Concern | | |
| Blue-gray taildropper | prophysaon coeruleum | Species of Concern | Wherever found | |
| Blue Grosbeak | Passerina caerulea | Species of Concern | Wherever found | |
| Bluehead Chub | Nocomis leptocephalus | Not Listed | | |
| Blue-headed macaw | Primolius couloni | Under Review | Wherever found | |
| Bluehead shiner | Pteronotropis hubbsi | Not Listed | Wherever found | |
| bluemask darter | Etheostoma akatulo | Endangered | Wherever found | 12-27-1993 |
| Blue Mountain onion | Allium dictuon | Species of Concern | Wherever found | |
| Blue Mountains cryptochian caddisfly | Cryptochia neosa | Species of Concern | Wherever found | |
| Blue Mountain Woodlandsnail | Ashmunella pilsbryana | Resolved Taxon | Wherever found | |
| Bluenose Shiner | Pteronotropis welaka | Not Listed | | |
| Blue oak | Quercus douglasii | Resolved Taxon | Wherever found | |
| Blue pike | Stizostedion vitreum glaucum | Extinction | Wherever found | 03-11-1967 |
| Blue Point pyrg | Pyrgulopsis coloradensis | Resolved Taxon | Wherever found | |
| Blue Ridge catchfly | Silene ovata | Species of Concern | Wherever found | |
| Blue Ridge goldenrod | Solidago spithamaea | Threatened | Wherever found | 03-28-1985 |
| Blue Ridge gray-cheeked salamander | Plethodon amplus | Resolved Taxon | Wherever found | |
| Blueridge springfly | Remenus kirchneri | Under Review | Wherever found | |
| Blue shiner | Cyprinella caerulea | Threatened | Wherever found | 04-22-1992 |
| Blue silverspot | Speyeria nokomis caerulescens | Species of Concern | Wherever found | |
| Blue Spring hydrobe | Aphaostracon asthenes | Status Undefined | Wherever found | |
| Bluestone sculpin | Cottus sp. | Species of Concern | Wherever found | |
| Bluestripe darter | Percina cymatotaenia | Under Review | Wherever found | |
| Bluestripe shiner | Cyprinella callitaenia | Status Undefined | Wherever found | |
| Blue sucker | Cycleptus elongatus | Species of Concern | Wherever found | |
| Blue-tailed ground lizard | Ameiva wetmorei | Species of Concern | Wherever found | |
| blue-tailed mole skink | Eumeces egregius lividus | Threatened | Wherever found | 11-06-1987 |
| Blue Talussnail | Sonorella caerulifluminis | Resolved Taxon | Wherever found | |
| Blue-throated Hummingbird | Lampornis clemenciae | Species of Concern | Wherever found | |
| Blue-throated macaw | Ara glaucogularis | Endangered | Wherever found | 10-03-2013 |
| Blue-throated (=ochre-marked) parakeet | Pyrrhura cruentata | Endangered | Wherever found | 06-02-1970 |
| blue tree monitor lizard | Varanus macraei | Emergency Listing, Endangered | | 12-26-2024 |
| Blue whale | Balaenoptera musculus | Endangered | Wherever found | 06-02-1970 |
| Blue-winged Warbler | Vermivora cyanoptera | Species of Concern | Wherever found | |
| Bluewing yellow-faced bee | Hylaeus caeruleipennis | Species of Concern | Wherever found | |
| Bluff Mountain Reindeer Lichen | Cladonia psoromica | Species of Concern | Wherever found | |
| blumberg rosita | centaurium blumbergianum | Resolved Taxon | Wherever found | |
| Blunt-nosed leopard lizard | Gambelia silus | Endangered | Wherever found | 03-11-1967 |
| Bluntnose Shiner | Notropis simus | Not Listed | | |
| Blyth's tragopan pheasant | Tragopan blythii | Endangered | Wherever found | 06-02-1970 |
| Boat-shaped Bugseed | Corispermum navicula | Resolved Taxon | Wherever found | |
| Bobcat | Lynx rufus | Resolved Taxon | Wherever found | |
| Bobolink | Dolichonyx oryzivorus | Species of Concern | Wherever found | |
| Bocaccio | Sebastes paucispinis | Endangered | Puget Sound-Georgia Basin DPS See 50 CFR 224.101 | 04-13-2011 |
| Bodie Hills draba | Cusickiella quadricostata | Species of Concern | Wherever found | |
| Bodie Hills rock-cress | Arabis bodiensis | Species of Concern | Wherever found | |
| Bog Asphodel | Narthecium americanum | Resolved Taxon | Wherever found | |
| Bog, Barnstable rush | Juncus pervetus | Resolved Taxon | Wherever found | |
| Bog bluegrass | Poa paludigena | Species of Concern | Wherever found | |
| bog buck moth | Hemileuca maia menyanthevora (=H. iroquois) | Endangered | Wherever found | 04-14-2023 |
| Bog coneflower | Rudbeckia scabrifolia | Species of Concern | Wherever found | |
| Bog elfin butterfly | Incisalia lanoraieensis | Resolved Taxon | Wherever found | |
| Bogg's Lake dodder | Cuscuta howelliana | Resolved Taxon | Wherever found | |
| Boggs Lake hedge-hyssop | Gratiola heterosepala | Resolved Taxon | Wherever found | |
| Bog idol leaf beetle | Donacia idola | Resolved Taxon | Wherever found | |
| Bog labordia | Labordia hedyosmifolia | Resolved Taxon | Wherever found | |
| Bogota rail | Rallus semiplumbeus | Candidate | Wherever found | |
| Bog spicebush | Lindera subcoriacea | Under Review | Wherever found | |
| bog turtle | Glyptemys muhlenbergii | Similarity of Appearance (Threatened) | U.S.A. (GA, NC, SC, TN, VA) | 11-04-1997 |
| bog turtle | Glyptemys muhlenbergii | Threatened | Wherever found, except GA, NC, SC, TN, VA | 11-04-1997 |
| Boharts' blue | Philotiella speciosa bohartorum | Species of Concern | Wherever found | |
| Boke's button cactus | Epithelantha bokei | Resolved Taxon | Wherever found | |
| Bolander's beach pine | Pinus contorta bolanderi | Species of Concern | Wherever found | |
| Bolander's horkelia | Horkelia bolanderi | Species of Concern | Wherever found | |
| Bolander's lily | Lilium bolanderi | Resolved Taxon | Wherever found | |
| Bolander's sagebrush | Artemisia cana bolanderi | Resolved Taxon | Wherever found | |
| Bolander water-hemlock | Cicuta bolanderi | Resolved Taxon | Wherever found | |
| Bolinas ceanothus | Ceanothus masonii | Species of Concern | Wherever found | |
| Bolivian short-tailed chinchilla | Chinchilla chinchilla boliviana | Endangered | Wherever found | 06-14-1976 |
| Bolson tortoise | Gopherus flavomarginatus | Endangered | Wherever found | 05-17-1979 |
| Bonaparte's Gull | Chroicocephalus philadelphia | Species of Concern | Wherever found | |
| Bone Cave harvestman | Texella reyesi | Endangered | Wherever found | 09-16-1988 |
| Bonin Flying Fox Bat | Pteropus pselaphon | Under Review | Wherever found | |
| Bonin Petrel | Pterodroma hypoleuca | Species of Concern | | |
| Bonita diving beetle | Deronectes neomexicana | Species of Concern | Wherever found | |
| Bonnethead | Sphyrna tiburo | Not Listed | | |
| Bonneville Cisco | Prosopium gemmifer | Resolved Taxon | Wherever found | |
| Bonneville cutthroat trout | Oncorhynchus clarkii utah | Resolved Taxon | Wherever found | |
| Bonneville southern pocket gopher | Thomomys umbrinus bonnevillei | Species of Concern | Wherever found | |
| Bonneville Whitefish | Prosopium spilonotus | Resolved Taxon | Wherever found | |
| Bonny Doon manzanita | Arctostaphylos silvicola | Species of Concern | Wherever found | |
| Bontebok | Damaliscus pygarus (=dorcas) dorcas | Endangered | Wherever found | 06-14-1976 |
| Bonytail | Gila elegans | Endangered | Wherever found | 04-23-1980 |
| Boott's rattlesnake root | Prenanthes boottii | Species of Concern | Wherever found | |
| Borax Lake chub | Gila boraxobius | Recovery | Wherever found | 05-28-1980 |
| Border Cave Amphipod | Stygobromus limbus | Resolved Taxon | Wherever found | |
| Boreal toad | Anaxyrus boreas boreas | Resolved Taxon | Eastern population | |
| Boreal toad | Anaxyrus boreas boreas | Resolved Taxon | Southern Rocky Mountain DPS | |
| Borneo earless monitor | Lanthanotus borneensis | Under Review | | |
| Borrego aster | Xylorhiza orcuttii | Species of Concern | Wherever found | |
| Borrego bedstraw | Galium angustifolium borregoense | Species of Concern | Wherever found | |
| Borrego Valley peppergrass | Lepidium flavum felipense | Species of Concern | Wherever found | |
| Botteri's Sparrow | Aimophila botterii | Species of Concern | Wherever found | |
| Boulder darter | Etheostoma wapiti | Endangered | Wherever found | 09-01-1988 |
| Boulder darter | Etheostoma wapiti | Experimental Population, Non-Essential | Shoal Creek (from Shoal Creek mile 41.7 (66.7 km)) at the mouth of Long Branch, Lawrence County, TN, downstream to the backwaters of Wilson Reservoir (Shoal Creek mile 14 (22 km)) at Goose Shoals, Lauderdale County, AL, including the lower 5 miles (8 km) of all tributaries that enter this reach. | 09-01-1988 |
| Boulder pile mountainsnail | Oreohelix jugalis | Species of Concern | Wherever found | |
| Boulder Slide Threeband | Humboldtiana edithae | Resolved Taxon | Wherever found | |
| Boulder snail | Leptoxis crassa | Species of Concern | Wherever found | |
| Boulder star coral | Orbicella franksi | Threatened | Wherever found | 11-13-2014 |
| Boulton's Amphipod | Stygobromus boultoni | Resolved Taxon | Wherever found | |
| Boundary Peak rock-cress | Boechera pinzliae | Species of Concern | Wherever found | |
| Bousfield's amphipod | Gammarus bousfieldi | Species of Concern | Wherever found | |
| Bowfin | Amia calva | Not Listed | | |
| Bowhead whale | Balaena mysticetus | Endangered | Wherever found | 06-02-1970 |
| Bowman's cave amphipod | Stygobromus bowmani | Resolved Taxon | Wherever found | |
| bowman's fairy shrimp | streptocephalus thomasbowmani | Resolved Taxon | Wherever found | |
| Boxfruit alani | Melicope peduncularis | Resolved Taxon | Wherever found | |
| Box huckleberry | Gaylussacia brachycera | Resolved Taxon | Wherever found | |
| Boykin's lobelia | Lobelia boykinii | Under Review | Wherever found | |
| Boynton's oak | Quercus boyntonii | Resolved Taxon | Wherever found | |
| Bracted twistflower | Streptanthus bracteatus | Threatened | Wherever found | 05-11-2023 |
| Bradshaw''s lomatium | Lomatium bradshawii | Recovery | Wherever found | 09-30-1988 |
| Bradshaw Talussnai | Sonorella bradshaveana | Resolved Taxon | Wherever found | |
| (Bradycellus fenderi) ground beetle | bradycellus fenderi | Species of Concern | Wherever found | |
| Brady pincushion cactus | Pediocactus bradyi | Endangered | Wherever found | 11-26-1979 |
| Braken Bat Cave meshweaver | Cicurina venii | Original Data in Error - Not a listable entity | Wherever found | 12-26-2000 |
| Branched draba | Draba stenoloba ramosa | Resolved Taxon | Wherever found | |
| Branched fleabane | Erigeron allocotus | Resolved Taxon | Wherever found | |
| Brandegee eriastrum | Eriastrum brandegeeae | Species of Concern | Wherever found | |
| Brandegee's Buckwheat | Eriogonum brandegeei | Resolved Taxon | Wherever found | |
| Brandegee's sage | Salvia brandegeei | Resolved Taxon | Wherever found | |
| Brand's phacelia | Phacelia stellaris | Resolved Taxon | Wherever found | |
| Brandt's Cormorant | Urile penicillatus | Species of Concern | | |
| Brasilia tapaculo | Scytalopus novacapitalis | Candidate | Wherever found | |
| Brassy Minnow | Hybognathus hankinsoni | Not Listed | | |
| Braun mato | Caesalpinia portoricensis | Resolved Taxon | Wherever found | |
| Braun's rock-cress | Arabis perstellata | Endangered | Wherever found | 01-03-1995 |
| Braunton's milk-vetch | Astragalus brauntonii | Endangered | Wherever found | 01-29-1997 |
| Brawleys Fork crayfish | Cambarus williami | Proposed Threatened | Wherever found | |
| Brazilian guitarfish | Rhinobatos horkelii | Endangered | | |
| Brazilian sideneck turtle | Phrynops hogei | Endangered | Wherever found | 09-30-1991 |
| Brazilian three-toed sloth | Bradypus torquatus | Endangered | Wherever found | 06-02-1970 |
| Brazillian merganser | Mergus octosetaceus | Endangered | Wherever found | 01-27-2011 |
| Brazoria Crayfish | Procambarus brazoriensis | Resolved Taxon | Wherever found | |
| Brazos River Yucca | Yucca necopina | Resolved Taxon | Wherever found | |
| Brazos water snake | Nerodia harteri harteri | Resolved Taxon | Wherever found | |
| Breckenridge Mountain slender salamander | Batrachoseps sp. | Species of Concern | Wherever found | |
| Brewer's dwarf-flax | Hesperolinon breweri | Species of Concern | Wherever found | |
| Brewer's Sparrow | Spizella breweri | Species of Concern | Wherever found | |
| Brewer's spineflower | Chorizanthe breweri | Resolved Taxon | Wherever found | |
| Brian Head Mountainsnail | Oreohelix parawanensis | Resolved Taxon | Wherever found | |
| Briarton Pleistocene snail | Vertigo briarensis | Species of Concern | Wherever found | |
| Bridewell's nesosydne planthopper | Nesosydne bridwelli | Species of Concern | Wherever found | |
| Bridgelip sucker | Catostomus columbianus | Status Undefined | Wherever found | |
| Bridges' Coast Range shoulderband | Helminthoglypta nickliniana bridgesi | Species of Concern | Wherever found | |
| Bridled darter | Percina kusha | Status Undefined | Wherever found | |
| Bridled Quail-Dove | Geotrygon mystacea | Species of Concern | Wherever found | |
| Bridled Tern | Onychoprion anaethetus | Species of Concern | | |
| Bridled Tern | Onychoprion anaethetus recongnitus | Species of Concern | | |
| Bridled white-eye | Zosterops conspicillatus conspicillatus | Extinction | Wherever found | 08-27-1984 |
| Bridled White-eye | Zosterops conspicillatus saypani | Species of Concern | Wherever found | |
| Bridle Shiner | Notropis bifrenatus | Not Listed | | |
| Bridwell's long-horned beetle | Plagithmysus bridwelli | Species of Concern | Wherever found | |
| Brikellbush aster | Eucephalus tomentellus | Resolved Taxon | Wherever found | |
| Briley Creek pyrg | Pyrgulopsis sp. | Species of Concern | Briley Creek | |
| Brindled Madtom | Noturus miurus | Not Listed | | |
| Brindled nail-tailed wallaby | Onychogalea fraenata | Endangered | Wherever found | 12-02-1970 |
| Bristlecone catseye | Cryptantha roosiorum | Species of Concern | Wherever found | |
| Bristle-flowered collomia | Collomia macrocalyx | Resolved Taxon | Wherever found | |
| Bristlefront yellow-faced bee | Nesoprosopis setosifrons | Resolved Taxon | Wherever found | |
| Bristle Nailwort | Paronychia lundelliorum | Resolved Taxon | Wherever found | |
| Bristle-thighed Curlew | Numenius tahitiensis | Species of Concern | Wherever found | |
| Brittlescale | Atriplex depressa | Status Undefined | Wherever found | |
| Britton's beargrass | Nolina brittoniana | Endangered | | 04-27-1993 |
| Broadhead yellow-faced bee | Hylaeus laticeps | Resolved Taxon | Wherever found | |
| Broad-leaf Ground-cherry | Physalis latiphysa | Resolved Taxon | Wherever found | |
| Broad-pod rushpea | Caesalpinia brachycarpa | Species of Concern | Wherever found | |
| Broad River Burrowing crayfish | Distocambarus devexus | Status Undefined | Wherever found | |
| Broad-snouted caiman | Caiman latirostris | Endangered | Bolivia, Brazil, Paraguay, and Uruguay | 06-14-1976 |
| Broad-snouted caiman | Caiman latirostris | Threatened | Argentina DPS | 06-14-1976 |
| Broadstripe shiner | Pteronotropis euryzonus | Status Undefined | Wherever found | |
| Broad-tailed Hummingbird | Selasphorus platycercus | Species of Concern | | |
| Broad Whitefish | Coregonus nasus | Not Listed | | |
| Broken hornsnail | Pleurocera postelli | Species of Concern | Wherever found | |
| Bronze clubtail | Stylurus townesi | Species of Concern | Wherever found | |
| Bronze darter | Percina palmaris | Resolved Taxon | Wherever found | |
| Brook elimia | Elimia strigosa | Species of Concern | Wherever found | |
| Brook floater | Alasmidonta varicosa | Resolved Taxon | Wherever found | |
| Brooksville bellflower | Campanula robinsiae | Endangered | | 07-27-1989 |
| brook trout | Salvelinus fontinalis | Resolved Taxon | anadromous (lake-run) | |
| brook trout | Salvelinus fontinalis | Status Undefined | Species as a whole (no specific population identified) | |
| Brother's Island tuatara | Sphenodon guntheri | Endangered | Wherever found | 06-02-1970 |
| Brother spike | Elliptio fraterna | Status Undefined | Wherever found | |
| Brown-banded antpitta | Grallaria milleri | Endangered | Wherever found | 11-29-2013 |
| Brown bear | Ursus arctos arctos | Endangered | Italy | 06-14-1976 |
| Brown bear | Ursus arctos pruinosus | Endangered | Wherever found | 06-14-1976 |
| Brown Booby | Sula leucogaster | Species of Concern | Wherever found | |
| Brown Bullhead | Ameiurus nebulosus | Not Listed | | |
| Brown Caiman | Caiman crocodilus fuscus (includes Caiman crocodilus chiapasius) | Similarity of Appearance (Threatened) | Wherever found | 05-04-2000 |
| Brown-capped Rosy-Finch | Leucosticte australis | Species of Concern | Wherever found | |
| Brown creeper | certhia americana | Species of Concern | Wherever found | |
| Brown-crested flycatcher | myiarchus tyrannulus | Species of Concern | Wherever found | |
| Brown cross ectemnius sphecid wasp | Ectemnius fulvicrus | Species of Concern | Wherever found | |
| Brown Darter | Etheostoma edwini | Not Listed | | |
| Brown eared pheasant | Crossoptilon mantchuricum | Endangered | Wherever found | 06-02-1970 |
| Brown-headed Nuthatch | Sitta pusilla | Species of Concern | Wherever found | |
| Brown Hyena | Parahyaena (=Hyaena) brunnea | Endangered | Wherever found | 06-02-1970 |
| Brownish dubiraphian riffle beetle | Dubiraphia brunnescens | Species of Concern | Wherever found | |
| Brown merycomyian tabanid fly | Merycomyia brunnea | Species of Concern | Wherever found | |
| Brown Pelican | Pelecanus occidentalis | Recovery | U.S. Atlantic coast, FL, AL | 06-02-1970 |
| Brown Pelican | Pelecanus occidentalis | Recovery | Wherever found, except U.S. Atlantic coast, FL, AL | 06-02-1970 |
| Brown Pelican | Pelecanus occidentalis | Resolved Taxon | Entire U.S., except Atlantic and Gulf Coast states, PR, U.S. VI | |
| Brown Pelican | Pelecanus occidentalis | Resolved Taxon | Louisiana population | |
| Brown Rockfish | Sebastes auriculatus | Not Listed | | |
| Brown's microcylloepus riffle beetle | Microcylloepus browni | Resolved Taxon | Wherever found | |
| Brown's optioservus riffle beetle | Optioservus browni | Species of Concern | Wherever found | |
| Brown springsnail | Pyrgulopsis sola | Resolved Taxon | Wherever found | |
| Brownsville common yellowthroat | Geothlypis trichas insperata | Species of Concern | Wherever found | |
| Brownsville Curve-billed Thrasher | Toxostoma curvirostre oberholseri | Species of Concern | | |
| Brown-tassel trigonoscuta weevil | Trigonoscuta brunneotesselata | Species of Concern | Wherever found | |
| Brown Thrasher | Toxostoma rufum | Species of Concern | Wherever found | |
| Brown Trout | Salmo trutta | Not Listed | | |
| Brown Trout | Salmo trutta | Status Undefined | Tiger trout (x Salvelinus fontinalis hybrid) | |
| Bruneau Hot springsnail | Pyrgulopsis bruneauensis | Endangered | Wherever found | 01-25-1993 |
| Brune's tryonia | Tryonia brunei | Resolved Taxon | Wherever found | |
| Brunson Mountain snail | Oreohelix speciesfive | Under Review | Wherever found | |
| Brush Prairie pocket gopher | Thomomys mazama douglasii | Resolved Taxon | Wherever found | |
| brush rabbit | Sylvilagus bachmani | Species of Concern | Wherever found | |
| Brush-tailed rat-kangaroo | Bettongia penicillata | Endangered | Wherever found | 12-02-1970 |
| Bryan's nehe | Lipochaeta bryanii | Resolved Taxon | Wherever found | |
| Bryan's oceanides seed bug | Oceanides bryani | Species of Concern | Wherever found | |
| Bryce bladder-pod | Lesquerella rubicundula | Resolved Taxon | Wherever found | |
| Bryson's sedge | Carex brysonii | Status Undefined | | |
| Buchholz' dart moth | Agrotis buchholzi | Species of Concern | Wherever found | |
| Buck Creek serpentine barren aster | Symphyotrichum rhiannon | Species of Concern | Wherever found | |
| Buck Darter | Etheostoma nebra | Species of Concern | | |
| Buena Vista Lake ornate Shrew | Sorex ornatus relictus | Endangered | Wherever found | 03-06-2002 |
| Buffalo Springs caddisfly | Ceratopsyche etnieri | Species of Concern | Wherever found | |
| Buff-banded Rail | Gallirallus philippensis goodsoni | Species of Concern | | |
| Buff-bellied Hummingbird | Amazilia yucatanensis | Species of Concern | Wherever found | |
| Buff-breasted flycatcher | Empidonax fulvifrons pygmaeus | Resolved Taxon | Wherever found | |
| Buff-breasted Flycatcher | Empidonax fulvifrons | Species of Concern | Wherever found | |
| Buff-breasted Sandpiper | Calidris subruficollis | Species of Concern | Wherever found | |
| Buff-headed marmoset | Callithrix flaviceps | Endangered | Wherever found | 01-23-1984 |
| Buller's Shearwater | Ardenna bulleri | Species of Concern | | |
| Bullfrog Mountain wild pea | Lathyrus hitchcockianus | Resolved Taxon | Wherever found | |
| Bullock's Oriole | Icterus bullockii | Species of Concern | Wherever found | |
| Bulls Island white-tailed deer | Odocoileus virginianus taurinsulae | Species of Concern | Wherever found | |
| Bull Trout | Salvelinus confluentus | Experimental Population, Non-Essential | Clackamas River subbasin and the mainstem Willamette River, from Willamette Falls to its points of confluence with the Columbia River, including Multnomah Channel | 12-09-2009 |
| Bull Trout | Salvelinus confluentus | Threatened | U.S.A., coterminous, (lower 48 states) | 06-10-1998 |
| Bulmer's fruit bat (=flying fox) | Aproteles bulmerae | Endangered | Wherever found | 01-23-1984 |
| Bulwer's Petrel | Bulweria bulwerii | Species of Concern | | |
| Bumblebee bat | Craseonycteris thonglongyai | Endangered | Wherever found | 01-23-1984 |
| Bumblebee scarab | Lichnanthe ursina | Species of Concern | Wherever found | |
| Bunched arrowhead | Sagittaria fasciculata | Endangered | Wherever found | 08-31-1979 |
| Bunched cory cactus | Coryphantha ramillosa | Threatened | Wherever found | 12-06-1979 |
| Burbot | Lota lota | Resolved Taxon | Wherever found | |
| Burke's goldfields | Lasthenia burkei | Endangered | Wherever found | 12-02-1991 |
| Burmese peacock turtle | Morenia ocellata | Endangered | Wherever found | 06-14-1976 |
| Burnell's false water penny | Acneus burnelli | Species of Concern | Wherever found | |
| Burnsville Cove cave amphipod | Stygobromus conradi | Species of Concern | Wherever found | |
| Burrhead Chub | Macrhybopsis marconis | Not Listed | | |
| Burrhead shiner | Notropis asperifrons | Resolved Taxon | Wherever found | |
| Burrington jumping-slug | Hemphillia burringtoni | Resolved Taxon | Wherever found | |
| Burro Grunt | Pomadasys crocro | Not Listed | | |
| Burrowing bog crayfish | Fallicambarus burrisi | Not Listed | Wherever found | |
| Burrowing mayfly | Hexagenia sp | Resolved Taxon | Wherever found | |
| Burrowing Owl | Athene cunicularia | Species of Concern | Wherever found | |
| Busck's gall moth | Carolella busckana | Species of Concern | Wherever found | |
| Bushy rush-rose | Helianthemum dumosum | Species of Concern | Wherever found | |
| Bushy whitlow-wort | Paronychia congesta | Proposed Endangered | | |
| Bushy wild-buckwheat | Eriogonum suffruticosum | Species of Concern | Wherever found | |
| Butte County catchfly | Silene occidentalis longistipitata | Species of Concern | Wherever found | |
| Butte County meadowfoam | Limnanthes floccosa ssp. californica | Endangered | Wherever found | 06-08-1992 |
| Butte County morning-glory | Calystegia atriplicifolia buttensis | Species of Concern | Wherever found | |
| Butte County sidalcea | Sidalcea robusta | Species of Concern | Wherever found | |
| Butte fritillary | Fritillaria eastwoodiae | Species of Concern | Wherever found | |
| buttercup phacelia | Phacelia covillei | Species of Concern | Wherever found | |
| Butterfield pyrg | Pyrgulopsis lata | Resolved Taxon | Wherever found | |
| Butterfly, Gaut's cactus | Turbinicarpus gautii | Resolved Taxon | Wherever found | |
| butterfly milkweed | Asclepias tuberosa | Not Listed | | |
| Butterfly Mussel | Ellipsaria lineolata | Not Listed | | |
| Butternut | Juglans cinerea | Species of Concern | Wherever found | |
| Butterworth's buckwheat | Eriogonum butterworthianum | Species of Concern | Wherever found | |
| Button's Sierra sideband | Monadenia mormonum buttoni | Species of Concern | Wherever found | |
| Bylas springsnail | Pyrgulopsis arizonae | Under Review | Wherever found | |
| Byrne Resort mountainsnail | Oreohelix spthirtyone | Resolved Taxon | Wherever found | |
| Cabot's tragopan pheasant | Tragopan caboti | Endangered | Wherever found | 06-02-1970 |
| Cabrera's hutia | Capromys angelcabrerai | Endangered | Wherever found | 05-16-1986 |
| Cache beardtongue | Penstemon compactus | Species of Concern | Wherever found | |
| Cache Peak buckwheat | Eriogonum kennedyi pinicola | Species of Concern | Wherever found | |
| Cactus ferruginous pygmy-owl | Glaucidium brasilianum cactorum | Threatened | Wherever found | 08-21-2023 |
| Cactus Wren | Campylorhynchus brunneicapillus guttatus | Species of Concern | Wherever found | |
| Caddisfly | Apatania arizona | Resolved Taxon | Wherever found | |
| Caddisfly | Chimarra primula | Resolved Taxon | Wherever found | |
| Caddisfly | Culoptila kimminsi | Resolved Taxon | Wherever found | |
| Caddisfly | Culoptila moselyi | Resolved Taxon | Wherever found | |
| Caddisfly | Hydroptila protera | Under Review | Wherever found | |
| Caddisfly | Lepidostoma ozarkense | Resolved Taxon | Wherever found | |
| Caddisfly | Neotrichia mobilensis | Resolved Taxon | Wherever found | |
| Caddisfly | Ochrotrichia guadalupensis | Resolved Taxon | Wherever found | |
| Caddisfly | Ochrotrichia weddleae | Resolved Taxon | Wherever found | |
| Caddisfly | Phylocentropus harrisi | Under Review | Wherever found | |
| Caddo madtom | Noturus taylori | Not Listed | Wherever found | |
| Caddo Mountain salamander | Plethodon caddoensis | Resolved Taxon | Wherever found | |
| Caddo purple false-foxglove | Tomanthera caddoensis | Species of Concern | Wherever found | |
| (Caecidotea reddelli) isopod | caecidotea reddelli | Species of Concern | Wherever found | |
| Caerulean Paradise flycatcher | Eutrichomyias rowleyi | Endangered | Wherever found | 01-16-2008 |
| Cagle's map turtle | Graptemys caglei | Resolved Taxon | Wherever found | |
| Cahaba elimia | Elimia cahawbensis | Resolved Taxon | Wherever found | |
| Cahaba pebblesnail | Clappia cahabensis | Resolved Taxon | Wherever found | |
| Cahaba pebblesnail | Clappia umbilicata | Resolved Taxon | Wherever found | |
| Cahaba saddle-case caddisfly | Protoptila cahabensis | Species of Concern | Wherever found | |
| Cahaba sandfiltering mayfly | Homoeoneuria cahabensis | Species of Concern | Wherever found | |
| Cahaba shiner | Notropis cahabae | Endangered | Wherever found | 10-25-1990 |
| Cain's reedgrass | Calamagrostis cainii | Species of Concern | Wherever found | |
| Calamianes (=Philippine) deer | Axis porcinus calamianensis | Endangered | Wherever found | 06-14-1976 |
| Calcasieu crayfish | Orconectes blacki | Under Review | Wherever found | |
| Calico monkeyflower | Mimulus pictus | Resolved Taxon | Wherever found | |
| Calico Rock oval | Patera clenchi | Species of Concern | Wherever found | |
| Caliente clarkia | Clarkia tembloriensis ssp. calientensis | Species of Concern | Wherever found | |
| California adder's-tongue | Ophioglossum lusitanicum | Resolved Taxon | Wherever found | |
| California adolphia | Adolphia californica | Species of Concern | Wherever found | |
| California Bay Shrimp | Crangon franciscorum | Not Listed | | |
| California beaked-rush | Rhynchospora californica | Species of Concern | Wherever found | |
| California black oak | Quercus kelloggii | Resolved Taxon | Wherever found | |
| California black rail | laterallus jamaicensis ssp. coturniculus | Species of Concern | Wherever found | |
| California bottlebrush grass | Elymus californicus | Resolved Taxon | Wherever found | |
| California condor | Gymnogyps californianus | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| California condor | Gymnogyps californianus | Experimental Population, Non-Essential | U.S.A. (Oregon, and specific portions of northern California and northwest Nevada) | 05-05-2019 |
| California condor | Gymnogyps californianus | Experimental Population, Non-Essential | U.S.A. (specific portions of Arizona, Nevada, and Utah)-see 17.84(j) | 10-16-1996 |
| California dichondra | Dichondra donnelliana | Resolved Taxon | Wherever found | |
| California diplectronan caddisfly | Diplectrona californica | Species of Concern | Wherever found | |
| California dissanthelium | Dissanthelium californicum | Species of Concern | Wherever found | |
| California ditaxis | Ditaxis serrata | Species of Concern | Wherever found | |
| California floater | Anodonta californiensis | Resolved Taxon | Wherever found | |
| California freshwater shrimp | Syncaris pacifica | Endangered | Wherever found | 10-31-1988 |
| California giant salamander | Dicamptodon ensatus | Resolved Taxon | Wherever found | |
| California golden trout | Oncorhynchus aguabonita | Resolved Taxon | Wherever found | |
| California Gull | Larus californicus | Not Listed | | |
| California hibiscus | Hibiscus californicus | Resolved Taxon | Wherever found | |
| California horned lark | Eremophila alpestris actia | Resolved Taxon | Wherever found | |
| California horned lizard | Phrynosoma coronatum frontale | Species of Concern | Wherever found | |
| California jewelflower | Caulanthus californicus | Endangered | Wherever found | 07-19-1990 |
| California king snake | lampropeltis getula ssp. californiae | Species of Concern | Wherever found | |
| California lady's-slipper | Cypripedium californicum | Resolved Taxon | Wherever found | |
| California leaf-nosed bat | Macrotus californicus | Species of Concern | Wherever found | |
| California least tern | Sternula antillarum browni | Endangered | Wherever found | 06-02-1970 |
| California linderiella | Linderiella occidentalis | Resolved Taxon | Wherever found | |
| California marina | Marina orcuttii orcuttii | Species of Concern | Wherever found | |
| California McCoy snail islandsnail | Micrarionta rowelli mccoiana | Species of Concern | Wherever found | |
| California mountain lion | Felis concolor californica | Resolved Taxon | Wherever found | |
| California muhly | Muhlenbergia californica | Species of Concern | Wherever found | |
| California myotis | myotis californicus | Species of Concern | Wherever found | |
| California Orcutt grass | Orcuttia californica | Endangered | Wherever found | 08-03-1993 |
| California penstemon | Penstemon californicus | Resolved Taxon | Wherever found | |
| California pine-foot | Pityopus californicus | Resolved Taxon | Wherever found | |
| California pitcherplant | Darlingtonia californica | Resolved Taxon | Wherever found | |
| California red-legged frog | Rana draytonii | Threatened | Wherever found | 05-23-1996 |
| California red tree vole | Arborimus pomo | Species of Concern | Wherever found | |
| California Ridgway''s rail | Rallus obsoletus obsoletus | Endangered | Wherever found | 10-13-1970 |
| California Roach | Hesperoleucus symmetricus | Not Listed | | |
| California seablite | Suaeda californica | Endangered | | 12-15-1994 |
| California Spotted Owl | Strix occidentalis occidentalis | Proposed Endangered | All California spotted owls in the vicinity of the Coast, Transverse, and Peninsular mountain ranges from Monterey County in the north to San Diego County in the south, and south of the Tehachapi Pass within Kern County. | |
| California Spotted Owl | Strix occidentalis occidentalis | Proposed Threatened | (All California spotted owls in the vicinity of the Sierra Nevada mountain range and the Sierra Nevada foothills from Shasta and Lassen Counties in the north, but north of the Tehachapi Pass, Kern County to the south, and east to Carson City, Douglas, and Washoe Counties in Nevada. | |
| California taraxacum | Taraxacum californicum | Endangered | Wherever found | 10-14-1998 |
| California Thrasher | Toxostoma redivivum | Species of Concern | Wherever found | |
| California tiger Salamander | Ambystoma californiense | Endangered | U.S.A. (CA - Santa Barbara County) | 01-19-2000 |
| California tiger Salamander | Ambystoma californiense | Endangered | U.S.A. (CA - Sonoma County) | 07-22-2002 |
| California tiger Salamander | Ambystoma californiense | Threatened | U.S.A. (CA - Central California) | 08-04-2004 |
| California walnut | Juglans californica var. californica | Species of Concern | Wherever found | |
| California wolverine | Gulo gulo luteus | Species of Concern | Wherever found | |
| Calistoga allocarya | Plagiobothrys strictus | Endangered | Wherever found | 10-22-1997 |
| Calistoga ceanothus | Ceanothus divergens | Species of Concern | Wherever found | |
| Calliope Hummingbird | Selasphorus calliope | Species of Concern | Wherever found | |
| Callippe silverspot butterfly | Speyeria callippe callippe | Endangered | Wherever found | 12-05-1997 |
| Calloway milk-vetch | Astragalus callithrix | Resolved Taxon | Wherever found | |
| Call's angelica | Angelica callii | Resolved Taxon | Wherever found | |
| Callused vertigo | Vertigo arthuri | Species of Concern | Wherever found | |
| Calvert's emerald | Somatochlora calverti | Under Review | Wherever found | |
| Cambria morning-glory | Calystegia subacaulis episcopalis | Species of Concern | Wherever found | |
| Cameroon clawless otter | Aonyx congicus (=congica) microdon | Endangered | Wherever found | 06-02-1970 |
| Cameroon toad | Bufo superciliaris | Endangered | Wherever found | 06-14-1976 |
| Campbell Island flightless teal | Anas aucklandica nesiotis | Endangered | Wherever found | 06-14-1976 |
| Camp Shelby burrowing crayfish | Fallicambarus gordoni | Resolved Taxon | Wherever found | |
| Camp Valley pyrg | Pyrgulopsis montana | Resolved Taxon | Wherever found | |
| Campylotheca bidens | Bidens campylotheca campylotheca | Resolved Taxon | Wherever found | |
| Canada goose | Branta canadensis | Status Undefined | Wherever found | |
| Canada Lynx | Lynx canadensis | Threatened | Wherever Found in Contiguous U.S. | 03-24-2000 |
| Canada Warbler | Cardellina canadensis | Species of Concern | Wherever found | |
| Canadian, columbine | Aquilegia canadensis australis | Species of Concern | Wherever found | |
| Canadian Toad | Anaxyrus hemiophrys | Not Listed | | |
| Canarian black oystercatcher | Haematopus meadewaldoi | Endangered | Wherever found | 01-12-1995 |
| Canary duskysnail | Lyogyrus spc | Resolved Taxon | Wherever found | |
| canary rockfish | Sebastes pinniger | Threatened | Puget Sound - Georgia Basin DPS See 50 CFR 223.102 | 04-13-2011 |
| Canby's dropwort | Oxypolis canbyi | Endangered | Wherever found | 02-25-1986 |
| Candleholder dudleya | Dudleya candelabrum | Species of Concern | Wherever found | |
| Candy darter | Etheostoma osburni | Endangered | Wherever found | 12-21-2018 |
| Cane Creek cave beetle | Pseudanophthalmus occidentalis | Species of Concern | Wherever found | |
| Canelo Hills ladies'-tresses | Spiranthes delitescens | Endangered | Wherever found | 01-06-1997 |
| Canescent bluebells | Mertensia viridis cana | Resolved Taxon | Wherever found | |
| Caney Mountain Cave Crayfish | Faxonius stygocaneyi | Not Listed | | |
| cannulate cave isopod | Caecidotea cannulus | Species of Concern | Wherever found | |
| cannulate cave isopod | Pseudobaicalasellus cannula | Under Review | Wherever found | |
| Canoe Creek Clubshell | Pleurobema athearni | Endangered | Wherever found | 08-05-2022 |
| Cantabrian capercaillie | Tetrao urogallus cantabricus | Endangered | Wherever found | 09-12-2011 |
| Cantelow's lewisia | Lewisia cantelowii | Resolved Taxon | Wherever found | |
| Canyon bat | Parastrellus hesperus | Species of Concern | Wherever found | |
| Canyon Creek stonecrop | Sedum paradisum | Species of Concern | Wherever found | |
| Canyon lip fern | Cheilanthes arizonica californicum | Resolved Taxon | Wherever found | |
| Canyon mock orange | Philadelphus ernestii | Species of Concern | Wherever found | |
| Canyon spotted whiptail | Cnemidophorus burti | Species of Concern | Wherever found | |
| Canyon Towhee | Pipilo fuscus | Species of Concern | Wherever found | |
| Capa rosa | Callicarpa ampla | Endangered | Wherever found | 04-22-1992 |
| Cape Fear shiner | Notropis mekistocholas | Endangered | Wherever found | 09-25-1987 |
| Cape Fear spike | Elliptio marsupiobesa | Resolved Taxon | Wherever found | |
| Cape Fear threetooth | Triodopsis soelneri | Species of Concern | Wherever found | |
| Cape May Warbler | Setophaga tigrina | Species of Concern | | |
| Cape Mendocino snail | Helminthoglypta arrosa mattolensis | Resolved Taxon | Wherever found | |
| Cape Mountain zebra | Equus zebra ssp. zebra | Endangered | | |
| Caper elimia | Elimia olivula | Not Listed | Wherever found | |
| Caper-fruited tropidocarpum | Tropidocarpum capparideum | Species of Concern | Wherever found | |
| Cape Sable orchid | Trichocentrum undulatum | Resolved Taxon | Wherever found | |
| Cape Sable seaside sparrow | Ammospiza maritima mirabilis | Endangered | Wherever found | 03-11-1967 |
| Cape Sable Thoroughwort | Chromolaena frustrata | Endangered | | 11-25-2013 |
| Capitan Woodlandsnail | Ashmunella pseudodonta | Resolved Taxon | Wherever found | |
| Capote Threeband | Humboldtiana fullingtoni | Resolved Taxon | Wherever found | |
| Capped Langur | Trachypithecus (=Presbytis) pileatus | Endangered | Wherever found | 06-14-1976 |
| Caracara commensal scarab | Trox howelli | Species of Concern | Wherever found | |
| Cardinal honey-eater | Myzomela cardinalis saffordi | Resolved Taxon | Wherever found | |
| Cardot's campylium moss | Campylium cardotii | Resolved Taxon | Wherever found | |
| Caribbean coot | Fulica caribaea | Species of Concern | Puerto Rican | |
| Caribbean monk seal | Monachus tropicalis | Extinction | Wherever found | 04-10-1979 |
| Caribbean Spiny Lobster | Panulirus argus | Not Listed | | |
| Carinated rocky mountainsnail | Oreohelix strigosa goniogyra | Species of Concern | Wherever found | |
| Carinate Glenwood Pyrg | Pyrgulopsis inopinata | Resolved Taxon | Wherever found | |
| Carinate Mountainsnail | Oreohelix elrodi | Resolved Taxon | Wherever found | |
| Carinate pillsnail | Euchemotrema hubrichti | Species of Concern | Wherever found | |
| Carite babyboot orchid | Lepanthes caritensis | Status Undefined | | |
| Carlow's Cave pseudoscorpion | Aphrastochthonius similis | Species of Concern | Wherever found | |
| Carlson's polycentropus caddisfly | Polycentropus carlsoni | Species of Concern | Wherever found | |
| Carmel Valley bush-mallow | Malacothamnus palmeri involucratus | Species of Concern | Wherever found | |
| Carmel Valley malacothrix | Malacothrix saxatilis arachnoidea | Species of Concern | Wherever found | |
| Carmine Shiner | Notropis percobromus | Not Listed | | |
| Carole's silverspot | Speyeria zerene carolae | Species of Concern | Wherever found | |
| Carolina birds-in-a-nest | Macbridea caroliniana | Not Listed | | |
| Carolina bishopweed | Ptilimnium ahlesii | Status Undefined | | |
| Carolina crawfish frog | Rana areolata capito | Species of Concern | Wherever found | |
| Carolina creekshell | Villosa vaughaniana | Species of Concern | Wherever found | |
| Carolina Darter | Etheostoma collis | Species of Concern | Wherever found | |
| Carolina elktoe | Alasmidonta robusta | Resolved Taxon | Wherever found | |
| Carolina goldenrod | Solidago pulchra | Species of Concern | Wherever found | |
| Carolina grass-of-parnassus | Parnassia caroliniana | Species of Concern | Wherever found | |
| Carolina heelsplitter | Lasmigona decorata | Endangered | Wherever found | 06-30-1993 |
| Carolina hemlock | Tsuga caroliniana | Under Review | Wherever found | |
| Carolina lead-plant | Amorpha georgiana confusa | Under Review | Wherever found | |
| Carolina Least Trillium | Trillium pusillum var. pusillum | Species of Concern | Wherever found | |
| Carolina madtom | Noturus furiosus | Endangered | Wherever found | 07-09-2021 |
| Carolina mnium | Plagiomnium carolinianum | Species of Concern | Wherever found | |
| Carolina northern flying squirrel | Glaucomys sabrinus coloratus | Endangered | Wherever found | 07-01-1985 |
| Carolina oatgrass | Danthonia epilis | Species of Concern | Wherever found | |
| Carolina pygmy sunfish | Elassoma boehlkei | Status Undefined | Wherever found | |
| Carolina skistodiaptomus | Skistodiaptomus carolinensis | Species of Concern | Wherever found | |
| Carolina Slabshell | Elliptio congaraea | Not Listed | | |
| Carolina sponge | Corvomeyenia carolinensis | Species of Concern | Wherever found | |
| Carolina well diacyclops | Diacyclops jeanneli putei | Species of Concern | Wherever found | |
| Carribean Brown Pelican | pelecanus occidentalis ssp. occidentalis | Species of Concern | Wherever found | |
| Carrizo Springs Texas pocket gopher | Geomys personatus streckeri | Species of Concern | Wherever found | |
| Carrollton crayfish | Procambarus connus | Species of Concern | Wherever found | |
| Carson Valley monkeyflower | Erythranthe carsonensis | Under Review | | |
| Carson Valley silverspot | Speyeria nokomis carsonensis | Resolved Taxon | Wherever found | |
| Carson Valley wood nymph | Cercyonis pegala carsonensis | Resolved Taxon | | |
| Carson wandering skipper | Pseudocopaeodes eunus obscurus | Endangered | Wherever found | 11-29-2001 |
| Carter's mustard | Warea carteri | Endangered | | 01-21-1987 |
| Carter's noctuid moth | Spartiniphaga carterae | Species of Concern | Wherever found | |
| Carter's panicgrass | Panicum fauriei var. carteri | Endangered | Wherever found | 10-12-1983 |
| Carter's small-flowered flax | Linum carteri carteri | Endangered | | 10-06-2014 |
| Cary beardtongue | Penstemon caryi | Species of Concern | Wherever found | |
| Cascade Cave amphipod | Stygobromus dejectus | Resolved Taxon | Wherever found | |
| Cascade Caverns salamander | Eurycea latitans | Under Review | Wherever found | |
| Cascade head catchfly | Silene douglasii oraria | Species of Concern | Wherever found | |
| Cascade red fox | Vulpes vulpes cascadensis | Status Undefined | | |
| Cascades apatanian caddisfly | Apatania tavala | Species of Concern | Wherever found | |
| Cascades frog | Rana cascadae | Resolved Taxon | Wherever found | |
| Cascade torrent salamander | Rhyacotriton cascadae | Under Review | Wherever found | |
| Casey's June Beetle | Dinacoma caseyi | Endangered | Wherever found | 10-24-2011 |
| Caspian Tern | Hydroprogne caspia | Species of Concern | Wherever found | |
| Cassia Crossbill | Loxia sinesciuris | Species of Concern | | |
| Cassin's Auklet | Ptychoramphus aleuticus | Species of Concern | Wherever found | |
| Cassin's Finch | Haemorhous cassinii | Species of Concern | Wherever found | |
| Cassin's Sparrow | Peucaea cassinii | Species of Concern | Wherever found | |
| Cassius Blue Butterfly | Leptotes cassius theonus | Similarity of Appearance (Threatened) | Wherever found | 04-06-2012 |
| Castetter milk-vetch | Astragalus castetteri | Resolved Taxon | Wherever found | |
| Castle Crags campanula | Campanula shetleri | Resolved Taxon | Wherever found | |
| Castle Crags rhyacophilan caddisfly | Rhyacophila lineata | Species of Concern | Wherever found | |
| Castle Lake rhyacophilan caddisfly | Rhyacophila amabilis | Resolved Taxon | Wherever found | |
| Cataiina beardtongue | Penstemon discolor | Species of Concern | Wherever found | |
| Catalina crossosoma | Crossosoma californicum | Resolved Taxon | Wherever found | |
| Catalina ironwood | Lyonothamnus floribundus floribundus | Species of Concern | Wherever found | |
| Catalina Island mountain-mahogany | Cercocarpus traskiae | Endangered | Wherever found | 08-08-1997 |
| Catalina mariposa lily | calochortus catalinae | Species of Concern | Wherever found | |
| Catalina mountainsnail | Radiocentrum avalonense | Species of Concern | Wherever found | |
| Catalina orange tip butterfly | Anthocharis cethura catalina | Resolved Taxon | Wherever found | |
| Catfish | Pangasius sanitwongsei | Endangered | Wherever found | 06-02-1970 |
| Cathedral snail | Micrarionta indioensis cathedralis | Resolved Taxon | Wherever found | |
| Catherine's cave beetle | Pseudanophthalmus catherinae | Species of Concern | Wherever found | |
| Cat Island turtle | Trachemys terrapen | Endangered | Cat Island in the Bahamas | 09-30-1991 |
| Catlow tui chub | Gila bicolor ssp. | Species of Concern | Catlow | |
| Catlow Valley redband trout | Oncorhynchus mykiss ssp. | Species of Concern | Catlow Valley | |
| Cauca guan | Penelope perspicax | Endangered | Wherever found | 11-29-2013 |
| Cave Creek Woodlandsnail | Ashmunella chiricahuana | Resolved Taxon | Wherever found | |
| Cave myotis | Myotis velifer | Species of Concern | Wherever found | |
| Cave Obligate Isopod | Amerigoniscus centralis | Under Review | Wherever found | |
| Cave physa | Physella spelunca | Resolved Taxon | Wherever found | |
| Cavern sheet-web spider | Islandiana speophila | Species of Concern | Wherever found | |
| Cave Salamander | Eurycea lucifuga | Not Listed | | |
| Cave Spring Cave spider | Nesticus jonesi | Species of Concern | Wherever found | |
| Cayman Brac ground iguana | Cyclura nubila caymanensis | Threatened | Wherever found | 06-22-1983 |
| Cazier's tiger beetle | Cicindela cazieri | Species of Concern | Wherever found | |
| Cebello halumtano | Bulbophyllum guamense | Threatened | Wherever found | 11-02-2015 |
| Cebolleta southern pocket gopher | Thomomys umbrinus paguatae | Species of Concern | Wherever found | |
| Cebu black shama (thrush) | Copsychus niger cebuensis | Endangered | Wherever found | 06-02-1970 |
| Cedar Breaks biscuitroot | Cymopterus minimus | Resolved Taxon | Wherever found | |
| Cedar Crest allocarya | Plagiobothrys glyptocarpus modestus | Species of Concern | Wherever found | |
| Cedar Key mole skink | Plestiodon egregius insularis | Proposed Endangered | Wherever found | |
| Cedros Island mule Deer | Odocoileus hemionus cerrosensis | Endangered | Wherever found | 10-28-1975 |
| Centerville brazos-mint | Brazoria pulcherrima | Resolved Taxon | Wherever found | |
| Central American river turtle | Dermatemys mawii | Endangered | Wherever found | 06-22-1983 |
| Central American tapir | Tapirus bairdii | Endangered | Wherever found | 06-02-1970 |
| Central Kentucky cave amphipod | Stygobromus exilis | Resolved Taxon | Wherever found | |
| Central Missouri cave amphipod | Allocrangonyx hubrichti | Species of Concern | Wherever found | |
| Central Mudminnow | Umbra limi | Not Listed | | |
| Central Stoneroller | Campostoma anomalum | Not Listed | | |
| Central Valley grasshopper | Conozoa hyalina | Resolved Taxon | Wherever found | |
| Ceraunus Blue Butterfly | Hemiargus ceraunus antibubastus | Similarity of Appearance (Threatened) | Wherever found | 04-06-2012 |
| Cerulean Warbler | Setophaga cerulea | Resolved Taxon | Wherever found | |
| Ceylon mugger crocodile | Crocodylus palustris kimbula | Endangered | Wherever found | 06-14-1976 |
| Chadwick Beach cotton mouse | Peromyscus gossypinus restrictus | Resolved Taxon | Wherever found | |
| Chaffey's cory cactus | Coryphantha chaffeyi | Species of Concern | Wherever found | |
| Chain Pickerel | Esox niger | Not Listed | | |
| Chambered nautilus | Nautilus pompilius | Threatened | | |
| Chamberlain's Dwarf salamander | Eurycea chamberlaini | Under Review | Wherever found | |
| Channel Catfish | Ictalurus punctatus | Not Listed | | |
| Channel Darter | Percina copelandi | Not Listed | | |
| Channeled pebblesnail | Somatogyrus wheeleri | Species of Concern | Wherever found | |
| Channel Islands dune beetle | Coelus pacificus | Species of Concern | Wherever found | |
| Channel Islands slender salamander | Batrachoseps pacificus pacificus | Species of Concern | Wherever found | |
| Channel Islands spotted skunk | Spilogale putorius amphiala | Species of Concern | Wherever found | |
| Channel Island tree poppy | Dendromecon rigida ssp. harfordii | Species of Concern | Wherever found | |
| Chaparral harebell | campanula exigua | Species of Concern | Wherever found | |
| Chapin Mesa milkvetch | Astragalus schmolliae | Resolved Taxon | | |
| Chapman rhododendron | Rhododendron chapmanii | Endangered | | 05-23-1979 |
| Chapman's aster | Symphyotrichum chapmanii | Species of Concern | Wherever found | |
| Chapman's butterwort | Pinguicula planifolia | Species of Concern | Wherever found | |
| Chapman's crownbeard | Verbesina chapmanii | Species of Concern | Wherever found | |
| Chapman's sedge | Carex chapmanii | Species of Concern | Wherever found | |
| Charleston Ant | Lasius nevadensis | Status Undefined | Wherever found | |
| Charleston beardtongue | penstemon leiophyllus var. keckii | Species of Concern | Wherever found | |
| Charlotte's phacelia | Phacelia nashiana | Species of Concern | Wherever found | |
| Charred volcanoes | Mycoporum biseptatum | Species of Concern | | |
| Chatham Island oystercatcher | Haematopus chathamensis | Candidate | Wherever found | |
| Chatham Island petrel | Pterodroma axillaris | Endangered | Wherever found | 09-14-2009 |
| Chatham Island pigeon | Hemiphaga novaeseelandiae chathamensis | Endangered | Wherever found | 06-02-1970 |
| Chatham Island robin | Petroica traversi | Endangered | Wherever found | 06-02-1970 |
| Chattahoochee Bass | Micropterus chattahoochae | Not Listed | | |
| Chattahoochee Crayfish | Cambarus howardi | Not Listed | | |
| Chattooga River crayfish | Cambarus scotti | Not Listed | Wherever found | |
| Chauga crayfish | Cambarus chaugaensis | Status Undefined | Wherever found | |
| Cheaha beloneurian stonefly | Beloneuria jamesae | Species of Concern | Wherever found | |
| Cheat minnow | Pararhinichthys bowersi | Species of Concern | Wherever found | |
| Cheat Mountain salamander | Plethodon nettingi | Threatened | Wherever found | 08-18-1989 |
| Checkered whiptail | Aspidoscelis tesselatus | Resolved Taxon | Wherever found | |
| Cheer pheasant | Catreus wallichii | Endangered | Wherever found | 09-28-1990 |
| Cheese-weed moth lacewing | Oliarces clara | Species of Concern | Wherever found | |
| Cheetah | Acinonyx jubatus | Endangered | Wherever found | 06-02-1970 |
| Chelan mountainsnail | Oreohelix sp | Not Listed | Wherever found | |
| Chelan rockmat | Petrophytum cinerascens | Species of Concern | Wherever found | |
| Cheoah Bald salamander | Plethodon cheoah | Resolved Taxon | Wherever found | |
| Chermock's mulberry wing skipper | Poanes massasoit chermocki | Species of Concern | Wherever found | |
| Cherokee clubtail | Gomphus consanguis | Under Review | Wherever found | |
| Cherokee darter | Etheostoma scotti | Threatened | Wherever found | 12-20-1994 |
| Cherrystone Drop | Hendersonia occulta | Not Listed | | |
| Cherry-throated tanager | Nemosia rourei | Endangered | Wherever found | 01-27-2011 |
| Chesapeake logperch | Percina bimaculata | Under Review | Wherever found | |
| Chestnut-backed Chickadee | Poecile rufescens rufescens | Species of Concern | | |
| Chestnut casebearer moth | Coleophora leucochrysella | Species of Concern | Wherever found | |
| Chestnut clearwing moth | Synanthedon castaneae | Resolved Taxon | Wherever found | |
| Chestnut-collared Longspur | Calcarius ornatus | Species of Concern | Wherever found | |
| Chestnut ermine moth | Argyresthia castaneela | Species of Concern | Wherever found | |
| Chestnut Lamprey | Ichthyomyzon castaneus | Not Listed | | |
| Chestnut leaf miner | Tischeria perplexa | Species of Concern | Wherever found | |
| Chickahominy water-hyssop | Bacopa rotundifolia | Resolved Taxon | Wherever found | |
| Chickamauga crayfish | Cambarus extraneus | Status Undefined | Wherever found | |
| Chickweed | Stellaria irrigua | Resolved Taxon | Wherever found | |
| chickweed oxytheca | Oxytheca caryophylloides | Species of Concern | Wherever found | |
| Chico Creek rock-cress | Arabis breweri austinae | Resolved Taxon | Wherever found | |
| Chihuahua catfish | Ictalurus sp. | Resolved Taxon | Wherever found | |
| Chihuahua chub | Gila nigrescens | Threatened | Wherever found | 10-11-1983 |
| Chihuahuan Raven | Corvus cryptoleucus | Species of Concern | | |
| Chihuahua scurfpea | Pediomelum pentaphyllum | Resolved Taxon | Wherever found | |
| Chihuahua shiner | Notropis chihuahua | Species of Concern | Wherever found | |
| Chilean false larch | Fitzroya cupressoides | Threatened | Wherever found | 12-07-1979 |
| Chilean woodstar | Eulidia yarrellii | Endangered | Wherever found | 09-16-2010 |
| Chiltan (=wild goat) markhor | Capra falconeri (=aegragrus) chiltanensis | Endangered | Wherever found | 06-14-1976 |
| Chimney Swift | Chaetura pelagica | Species of Concern | Wherever found | |
| Chimpanzee | Pan troglodytes | Endangered | Wherever found | 09-14-2015 |
| Chinese alligator | Alligator sinensis | Endangered | Wherever found | 06-14-1976 |
| Chinese Camp brodiaea | Brodiaea pallida | Threatened | Wherever found | 10-14-1998 |
| Chinese egret | Egretta eulophotes | Endangered | Wherever found | 06-02-1970 |
| Chinese giant salamander | Andrias davidianus (=davidianus d.) | Endangered | Wherever found | 06-14-1976 |
| Chinese monal pheasant | Lophophorus lhuysii | Endangered | Wherever found | 06-02-1970 |
| Chinese pangolin | Manis pentadactyla | Under Review | Wherever found | |
| Chinese River Dolphin | Lipotes vexillifer | Endangered | Wherever found | 05-30-1989 |
| Chinese sturgeon | Acipenser sinensis | Endangered | Wherever found | 09-04-2014 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Endangered | Sacramento River winter-run ESU - See 50 CFR 224.101 | 04-06-1990 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Endangered | Upper Columbia River spring-run ESU See 50 CFR 224.101 | 08-02-1999 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Experimental Population, Non-Essential | Central Valley spring-run ESU–XN Shasta - See 50 CFR 223.102 | |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Experimental Population, Non-Essential | Central Valley spring-run ESU–XN Yuba - See 50 CFR 223.102 | |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Experimental Population, Non-Essential | Sacramento River winter-run ESU–XN Shasta - See 50 CFR 223.102 | |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | California Coastal ESU - See 50 CFR 223.102 | 12-29-1999 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Central Valley spring-run ESU See 50 CFR 223.102 | 12-29-1999 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Lower Columbia River ESU See 50 CFR 223.102 | 08-02-1999 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Puget Sound ESU See 50 CFR 223.102 | 08-02-1999 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Snake River fall-run ESU See 50 CFR 223.102 | 04-22-1992 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Snake River spring/summer-run ESU See 50 CFR 223.102 | 04-22-1992 |
| Chinook salmon | Oncorhynchus (=Salmo) tshawytscha | Threatened | Upper Willamette River ESU See 50 CFR 223.102 | 08-02-1999 |
| Chipola slabshell | Elliptio chipolaensis | Threatened | Wherever found | 03-16-1998 |
| Chipping Sparrow | Spizella passerina | Species of Concern | Wherever found | |
| Chiricahua dock | Rumex orthoneurus | Resolved Taxon | Wherever found | |
| Chiricahua fleabane | Erigeron kuschei | Resolved Taxon | Wherever found | |
| Chiricahua leopard frog | Rana chiricahuensis | Threatened | Wherever found | 06-13-2002 |
| Chiricahua mudwort | Limosella pubiflora | Species of Concern | Wherever found | |
| Chiricahua Nayarit squirrel | Sciurus nayaritensis chiricahuae | Species of Concern | Wherever found | |
| Chiricahua rock-daisy | Perityle cochisensis | Resolved Taxon | Wherever found | |
| Chiricahua water scavenger beetle | Cymbiodyta arizonica | Species of Concern | Wherever found | |
| Chiricahua western harvest mouse | Reithrodontomys megalotis arizonensis | Species of Concern | Wherever found | |
| Chiselmouth | Acrocheilus alutaceus | Not Listed | | |
| Chisos agave | Agave glomeruliflora | Species of Concern | Wherever found | |
| Chisos Foxsnail | Pseudosubulina cheatumi | Resolved Taxon | Wherever found | |
| chisos metalmark | apodemia chisosensis | Resolved Taxon | Wherever found | |
| Chisos Mountain crested coralroot | Bletia revoluta | Under Review | Wherever found | |
| Chisos Mountain hedgehog Cactus | Echinocereus chisoensis var. chisoensis | Threatened | Wherever found | 09-30-1988 |
| Chisos Mountains oak | Quercus tardifolia | Resolved Taxon | Wherever found | |
| Chisos pinweed | Lechea mensalis | Resolved Taxon | Wherever found | |
| Chisos Threeband | Humboldtiana chisosensis | Resolved Taxon | Wherever found | |
| Chittenango ovate amber snail | Novisuccinea chittenangoensis | Threatened | Wherever found | 08-02-1978 |
| Chlorostictan yellow-faced bee | Hylaeus chlorosticata | Species of Concern | Wherever found | |
| Choctaw bean | Obovaria choctawensis | Endangered | Wherever found | 10-10-2012 |
| Choctawhatchee beach mouse | Peromyscus polionotus allophrys | Endangered | Wherever found | 06-06-1985 |
| Chorro Creek bog thistle | Cirsium fontinale var. obispoense | Endangered | Wherever found | 12-15-1994 |
| Chorro shoulderband snail | Helminthoglypta morroensis | Resolved Taxon | | |
| Chowanoke crayfish | Faxonius virginiensis | Resolved Taxon | Wherever found | |
| Christmas Island goshawk | Accipiter fasciatus natalis | Endangered | Wherever found | 06-02-1970 |
| Christmas Island Pipistrelle Bat | Pipistrellus murrayi | Under Review | Wherever found | |
| Christmas Shearwater | Puffinus nativitatis | Species of Concern | Wherever found | |
| Christ's paintbrush | Castilleja christii | Resolved Taxon | Wherever found | |
| Chryxus arctic butterfly | Oeneis chryxus valerata | Resolved Taxon | Wherever found | |
| Chuckwalla | Sauromalus ater | Species of Concern | Wherever found | |
| Chuck-will's-widow | Antrostomus carolinensis | Species of Concern | Wherever found | |
| Chucky Madtom | Noturus crypticus | Endangered | Wherever found | 09-08-2011 |
| Chukcho stonefly | Haploperla chukcho | Species of Concern | Wherever found | |
| Chum salmon | Oncorhynchus keta | Threatened | Columbia River ESU See 50 CFR 223.102 | 08-02-1999 |
| Chum salmon | Oncorhynchus keta | Threatened | Hood Canal summer-run ESU - See 50 CFR 223.102 | 08-02-1999 |
| Chupacallos | Pleodendron macranthum | Endangered | Wherever found | 11-25-1994 |
| Chupadera springsnail | Pyrgulopsis chupaderae | Endangered | Wherever found | 08-13-2012 |
| Churchill Narrows buckwheat | Eriogonum diatomaceum | Resolved Taxon | Wherever found | |
| Cicek (minnow) | Acanthorutilus handlirschi | Endangered | Wherever found | 06-02-1970 |
| Cienega Seca oxytheca | Oxytheca parishii ciengensis | Species of Concern | Wherever found | |
| Ciervo aegialian scarab | Aegialia concinna | Species of Concern | Wherever found | |
| Ciliate-leaf tickseed | Coreopsis integrifolia | Under Review | Wherever found | |
| Cima rattleweed | Astragalus cimae cimae | Resolved Taxon | Wherever found | |
| Cimarron wild-buckwheat | Eriogonum aliquantum | Resolved Taxon | Wherever found | |
| Cinder phacelia | Phacelia serrata | Species of Concern | Wherever found | |
| Cinnamon juga | Juga canella | Resolved Taxon | Wherever found | |
| Cinnamon pika | Ochotona princeps cinnamomea | Species of Concern | Wherever found | |
| [Cisco] milkvetch | Astragalus sabulosus | Resolved Taxon | Wherever found | |
| Clackamas iris | Iris tenuis | Resolved Taxon | Wherever found | |
| Clam-shell orchid | Encyclia cochleata var. triandra | Resolved Taxon | Wherever found | |
| Clanton's cave amphipod | Stygobromus clantoni | Species of Concern | Wherever found | |
| Clapper rail | Rallus longirostris | Species of Concern | Wherever found | |
| Clapper Rail | Rallus crepitans | Species of Concern | | |
| Clara Hunt's milk-vetch | Astragalus clarianus | Endangered | Wherever found | 10-22-1997 |
| Clarke's weaver | Ploceus golandi | Endangered | Wherever found | 01-12-1995 |
| Clark Mountain buckwheat | Eriogonum heermannii floccosum | Resolved Taxon | Wherever found | |
| Clark Mountains agave | Agave utahensis nevadensis | Resolved Taxon | Wherever found | |
| Clark Peak talussnail | Sonorella christenseni | Resolved Taxon | Wherever found | |
| Clark's gazelle | Ammodorcas clarkei | Endangered | Wherever found | 06-02-1970 |
| Clark's Grebe | Aechmophorus clarkii | Species of Concern | | |
| Clark's Nutcracker | Nucifraga columbiana | Species of Concern | Wherever found | |
| Clatsop philocascan caddisfly | Philocasca oron | Species of Concern | Wherever found | |
| Clausen's Violet | Viola clauseniana | Resolved Taxon | Wherever found | |
| Clay bindweed | convolvulus equitans | Species of Concern | Wherever found | |
| Clay blazing-star | Mentzelia argillosa | Species of Concern | Wherever found | |
| Clay-Loving wild buckwheat | Eriogonum pelinophilum | Endangered | Wherever found | 07-13-1984 |
| Clay phacelia | Phacelia argillacea | Endangered | Wherever found | 10-29-1978 |
| Clay reed-mustard | Schoenocrambe argillacea | Threatened | Wherever found | 01-14-1992 |
| Clay's hibiscus | Hibiscus clayi | Endangered | Wherever found | 02-25-1994 |
| Clayton's copper | Lycaena dorcas claytoni | Species of Concern | Wherever found | |
| Clear Creek Amphipod | Hyalella texana | Resolved Taxon | Wherever found | |
| Clear Creek fleabane | Erigeron religiosus | Resolved Taxon | Wherever found | |
| Clear Creek gambusia | Gambusia heterochir | Endangered | Wherever found | 03-11-1967 |
| Clear Lake Hitch | Lavinia exilicauda chi | Proposed Threatened | Wherever found | |
| Clear Lake pocket gopher | Thomomys umbrinus convexus | Species of Concern | Wherever found | |
| Clear Lake splittail | Pogonichthys ciscoides | Resolved Taxon | Wherever found | |
| Clearwater phlox | Phlox idahonis | Species of Concern | Wherever found | |
| Cleft, phlox | Phlox bifida stellaria | Species of Concern | Wherever found | |
| Clemence's fritillary butterfly | Speyeria adiaste clemencei | Resolved Taxon | Wherever found | |
| Cleveland's bush monkeyflower | Diplacus clevelandii | Species of Concern | Wherever found | |
| Cliff bedstraw | Galium correllii | Species of Concern | Wherever found | |
| cliff cinquefoil | Potentilla rimicola | Species of Concern | Wherever found | |
| Cliff daisy | Erigeron proselyticus | Resolved Taxon | Wherever found | |
| Cliffdweller's candlestick catseye | Cryptantha elata | Resolved Taxon | Wherever found | |
| Cliff milk-vetch | Astragalus cremnophylax myriorrhaphis | Species of Concern | Wherever found | |
| Cliff-palace milk-vetch | Astragalus deterior | Species of Concern | Wherever found | |
| Cliff spurge | euphorbia misera | Species of Concern | Wherever found | |
| Clifton Cave beetle | Pseudanophthalmus caecus | Resolved Taxon | Wherever found | |
| Clifton Cave isopod | Caecidotea barri | Species of Concern | Wherever found | |
| Clifton Spring Hydrobe snail | Aphaostracon theiocrenetum | Status Undefined | Wherever found | |
| Climbing dayflower | Commelina gigas | Resolved Taxon | Wherever found | |
| Clinch dace | Chrosomus sp. cf. saylori | Under Review | | |
| Clingman covert | Mesodon clingmanicus | Species of Concern | Wherever found | |
| Clokey greasebush | glossopetalon clokeyi | Species of Concern | Wherever found | |
| Clokey paintbrush | Castilleja applegatei ssp. martinii | Species of Concern | Wherever found | |
| Clokey's egg-vetch | Astragalus oophorus clokeyanus | Resolved Taxon | Wherever found | |
| Clokey's forsellesia | Glossopetalon clokeyi | Species of Concern | Wherever found | |
| Clokey's thistle | Cirsium clokeyi | Resolved Taxon | Wherever found | |
| Closed-lip beardtongue | Penstemon personatus | Species of Concern | Wherever found | |
| Clouded leopard | Neofelis nebulosa | Endangered | Wherever found | 06-02-1970 |
| Clouded Salamander | Aneides ferreus | Not Listed | | |
| Clouded tailed copper butterfly | Lycaena arota nubila | Resolved Taxon | Wherever found | |
| Cloven-feathered dove | Drepanoptila holosericea | Endangered | Wherever found | 06-02-1970 |
| Clover''s cactus | Sclerocactus cloverae | Under Review | | |
| Clover (Tidestrom''s) lupine | Lupinus tidestromii | Endangered | Wherever found | 06-22-1992 |
| Clover Valley speckled dace | Rhinichthys osculus oligoporus | Endangered | Wherever found | 10-10-1989 |
| Clubshell | Pleurobema clava | Endangered | Wherever found; Except where listed as Experimental Populations | 01-22-1993 |
| Clubshell | Pleurobema clava | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Clustered lady's-slipper | Cypripedium fasciculatum | Species of Concern | Wherever found | |
| Coachella giant sand treader cricket | Macrobaenetes valgum | Species of Concern | Wherever found | |
| Coachella Valley fringe-toed lizard | Uma inornata | Threatened | Wherever found | 09-25-1980 |
| Coachella Valley jerusalem cricket | Stenopelmatus cahuilaensis | Species of Concern | Wherever found | |
| Coachella Valley milk-vetch | Astragalus lentiginosus var. coachellae | Endangered | Wherever found | 10-06-1998 |
| Coal darter | Percina brevicauda | Proposed Threatened | Wherever found | |
| Coal elimia | Elimia aterina | Species of Concern | Wherever found | |
| Coaltown sagebrush | Artemisia argilosa | Resolved Taxon | Wherever found | |
| Coalville mountainsnail | Oreohelix peripherica weberiana | Resolved Taxon | Wherever found | |
| Coastal bluff bentgrass | Agrostis clivicola clivicola | Resolved Taxon | Wherever found | |
| Coastal California gnatcatcher | Polioptila californica californica | Threatened | Wherever found | 03-30-1993 |
| Coastal cutthroat Trout | Oncorhynchus clarkii clarkii | Original Data in Error - Taxonomic Revision | Umpqua R. (U.S.A._OR) naturally spawning populations in mainstem and tributaries | 09-13-1996 |
| Coastal cutthroat Trout | Oncorhynchus clarkii clarkii | Resolved Taxon | Southwestern WA/Columbia R. (U.S.A._OR, WA) naturally spawning populations (and their progeny) below natural barriers in Columbia R. and its tributaries downstream from Klickitat R. (WA) and Fifteenmile Cr. (OR), inclusive, including Willamette R. downstream from Willamette Falls, and in coastal drainages between Columbia R. and Grays Harbor (WA), inclusive | |
| Coastal cutthroat Trout | Oncorhynchus clarkii clarkii | Status Undefined | Species as a whole (populations not monitored for specific population goals) | |
| Coastal dunes milk-vetch | Astragalus tener var. titi | Endangered | Wherever found | 08-12-1998 |
| Coastal Flatwoods crayfish | Procambarus apalachicolae | Under Review | Wherever found | |
| Coastal Lowland Cave crayfish | Procambarus leitheuseri | Under Review | Wherever found | |
| Coastal rainbow trout | oncorhynchus mykiss ssp. irideus | Species of Concern | Wherever found | |
| Coastal Roach | Hesperoleucus venustus | Not Listed | | |
| Coastal rosy boa | Charina trivirgata roseofusca | Species of Concern | Wherever found | |
| Coastal (WayneÂ’s) Black-throated Green Warbler | Setophaga virens waynei | Species of Concern | | |
| Coastal western whiptail | Cnemidophorus tigris multiscutatus | Species of Concern | Wherever found | |
| Coast barrel cactus | Ferocactus viridescens | Species of Concern | Wherever found | |
| Coast lily | Lilium maritimum | Species of Concern | Wherever found | |
| Coast patch-nosed snake | Salvadora hexalepis virgultea | Species of Concern | Wherever found | |
| Coast range newt | taricha torosa ssp. torosa | Species of Concern | Wherever found | |
| Coastrange Sculpin | Cottus aleuticus | Not Listed | | |
| Coast rock-cress | Arabis blepharophylla | Resolved Taxon | Wherever found | |
| Coast wallflower | Erysimum ammophilum | Species of Concern | Wherever found | |
| Cobana negra | Stahlia monosperma | Threatened | Wherever found | 04-05-1990 |
| Cobble elimia | Elimia vanuxemiana | Not Listed | Wherever found | |
| Cobblestone tiger beetle | Cicindela marginipennis | Resolved Taxon | Wherever found | |
| Cobb Mountain lupine | Lupinus sericatus | Resolved Taxon | Wherever found | |
| Cobia | Rachycentron canadum | Not Listed | | |
| Cobweb hymenopappus | Hymenopappus filifolius tomentosus | Resolved Taxon | Wherever found | |
| Cochise pincushion cactus | Coryphantha robbinsorum | Threatened | Wherever found | 01-09-1986 |
| Cochito | Phocoena sinus | Endangered | Wherever found | 01-09-1985 |
| Cockerell Holospira | Holospira cockerelli | Resolved Taxon | Wherever found | |
| Cockerell's striate disc | Discus shemeki cockerelli | Species of Concern | Wherever found | |
| Cockle elimia | Elimia cochliaris | Under Review | Wherever found | |
| Coconino Arizona pocket mouse | Perognathus amplus ammodytes | Species of Concern | Wherever found | |
| Codfish Island fernbird | Bowdleria punctata wilsoni | Under Review | Wherever found | |
| Coeur d'Alene salamander | Plethodon idahoensis | Resolved Taxon | Wherever found | |
| Coffin Cave mold beetle | Batrisodes texanus | Endangered | Wherever found | 09-16-1988 |
| Cognatus eopenthes click beetle | Eopenthes cognatus | Species of Concern | Wherever found | |
| Coho salmon | Oncorhynchus (=Salmo) kisutch | Endangered | Central California Coast ESU - See 50 CFR 224.101 | 11-20-1996 |
| Coho salmon | Oncorhynchus (=Salmo) kisutch | Threatened | Lower Columbia River ESU - See 50 CFR 223.102 | 06-28-2005 |
| Coho salmon | Oncorhynchus (=Salmo) kisutch | Threatened | Oregon Coast ESU - See 50 CFR 223.102 | 04-13-2011 |
| Coho salmon | Oncorhynchus (=Salmo) kisutch | Threatened | Southern Oregon - Northern California Coast ESU - See 50 CFR 223.102 | 06-18-1997 |
| Cokendolpher Cave Harvestman | Texella cokendolpheri | Endangered | Wherever found | 12-26-2000 |
| Cold Spring caddisfly | Lepidostoma ermanae | Species of Concern | Wherever found | |
| Coldwater crayfish | Faxonius eupunctus | Resolved Taxon | Wherever found | |
| Coldwater darter | Etheostoma ditrema | Species of Concern | Wherever found | |
| Coldwater elimia | Elimia gerhardti | Resolved Taxon | Wherever found | |
| Coleman Cave beetle | Pseudanophthalmus colemanensis | Under Review | Wherever found | |
| Colemans coralroot | Hexalectris colemanii | Resolved Taxon | Wherever found | |
| Colima Warbler | Leiothlypis crissalis | Resolved Taxon | Wherever found | |
| Colonial pocket gopher | Geomys colonus | Resolved Taxon | Wherever found | |
| Colorado burrowing mayfly | Ephemera compar | Resolved Taxon | Wherever found | |
| Colorado Buttercup | Ranunculus coloradensis | Resolved Taxon | Wherever found | |
| Colorado Butterfly plant | Gaura neomexicana var. coloradensis | Recovery | Wherever found | 10-18-2000 |
| Colorado delta clam | Mulinia coloradoensis | Candidate | | |
| Colorado Desert fringed-toed lizard | Uma notata | Resolved Taxon | Wherever found | |
| Colorado Groundwater Amphipod | Stygobromus coloradensis | Resolved Taxon | Wherever found | |
| Colorado hog-nosed skunk | Conepatus mesoleucus figginsi | Species of Concern | Wherever found | |
| Colorado hookless Cactus | Sclerocactus glaucus | Threatened | Wherever found | 10-11-1979 |
| Colorado pikeminnow | Ptychocheilus lucius | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Colorado pikeminnow | Ptychocheilus lucius | Experimental Population, Non-Essential | Salt and Verde R. drainages, AZ | 07-24-1985 |
| Colorado River cotton rat | Sigmodon arizonae plenus | Species of Concern | Wherever found | |
| Colorado River cutthroat trout | Oncorhynchus clarkii pleuriticus | Resolved Taxon | Wherever found | |
| Colorado River toad | bufo alvarius | Species of Concern | Wherever found | |
| Colton Sand Dune Jerusalem cricket | Stenopelmatus spp | Resolved Taxon | Wherever found | |
| Columbia Duskysnail | Lyogyrus sp | Resolved Taxon | Wherever found | |
| Columbia Gorge neothremman caddisfly | Neothremma andersoni | Species of Concern | Wherever found | |
| Columbia milk-vetch | Astragalus columbianus | Species of Concern | Wherever found | |
| Columbian sharp-tailed grouse | Tympanuchus phasianellus columbianus | Resolved Taxon | Wherever found | |
| Columbian white-tailed deer | Odocoileus virginianus leucurus | Recovery | Douglas County, Oregon | 03-11-1967 |
| Columbian white-tailed deer | Odocoileus virginianus leucurus | Threatened | Columbia River (Clark, Cowliz, Pacific, Skamania, and Wahkiakum Counties, WA., and Clatsop, Columbia, and Multnomah Counties, OR.) | 03-11-1967 |
| Columbian whitetop aster | Sericocarpus rigidus | Species of Concern | Wherever found | |
| Columbia Oregonian | Cryptomastix hendersoni | Resolved Taxon | Wherever found | |
| Columbia pebblesnail | Fluminicola columbiana | Resolved Taxon | Wherever found | |
| Columbia River Redband | Oncorhynchus mykiss gairdnerii | Resolved Taxon | Wherever found | |
| Columbia River smelt | Thaleichthys pacificus | Resolved Taxon | Wherever found | |
| Columbia River tiger beetle | Cicindela columbica | Resolved Taxon | Wherever found | |
| Columbia spotted frog | Rana luteiventris | Resolved Taxon | Great Basin DPS | |
| Columbia spotted frog | Rana luteiventris | Resolved Taxon | main pop. | |
| Columbia springsnail | Pyrgulopsis | Resolved Taxon | Wherever found | |
| Columbia torrent salamander | Rhyacotriton kezeri | Under Review | Wherever found | |
| Columbia yellow-cress | Rorippa columbiae | Resolved Taxon | Wherever found | |
| Colusa grass | Neostapfia colusana | Threatened | Wherever found | 03-26-1997 |
| Comal blind salamander | Eurycea tridentifera | Not Listed | Wherever found | |
| comal siltsnail | marstonia comalensis | Resolved Taxon | Wherever found | |
| Comal snakewood | Colubrina stricta | Species of Concern | Wherever found | |
| Comal Springs Diving Beetle | Comaldessus stygius | Resolved Taxon | Wherever found | |
| Comal Springs dryopid beetle | Stygoparnus comalensis | Endangered | Wherever found | 12-18-1997 |
| Comal Springs riffle beetle | Heterelmis comalensis | Endangered | Wherever found | 12-18-1997 |
| Comal Springs salamander | Eurycea species | Not Listed | Wherever found | |
| Comal Springs salamander | Eurycea species | Resolved Taxon | Wherever found | |
| Comal Springs Salamander | Eurycea sp. | Not Listed | | |
| Comanche layia | Layia leucopappa | Species of Concern | Wherever found | |
| Comanche-peak prairie-clover | Dalea reverchonii | Species of Concern | Wherever found | |
| Comanche Springs pupfish | Cyprinodon elegans | Endangered | Wherever found | 03-11-1967 |
| Combleaf | Polyctenium williamsiae | Resolved Taxon | Wherever found | |
| Comb Wash wild-buckwheat | Eriogonum clavellatum | Resolved Taxon | Wherever found | |
| Comes yellow-faced bee | Hylaeus communis | Species of Concern | Wherever found | |
| Common Arrowhead | Sagittaria latifolia | Not Listed | | |
| Common Black-Hawk | Buteogallus anthracinus | Species of Concern | Wherever found | |
| Common caiman | Caiman crocodilus crocodilus | Similarity of Appearance (Threatened) | Wherever found | 05-04-2000 |
| Common eelgrass | Zostera marina | Not Listed | | |
| Common Eider | Somateria mollissima | Species of Concern | Wherever found | |
| Common eopenthes click beetle | Eopenthes plebeius | Species of Concern | Wherever found | |
| Common Ground-Dove | Columbina passerina exigua | Species of Concern | Wherever found | |
| Common Guitarfish | Rhinobatos rhinobatos | Threatened | | |
| Common Hippopotamus | Hippopotamus amphibius | Not Listed | | |
| Common loon | gavia immer | Species of Concern | Wherever found | |
| Common Murre | Uria aalge | Species of Concern | Wherever found | |
| Common Nighthawk | Chordeiles minor | Species of Concern | Wherever found | |
| Common Poorwill | Phalaenoptilus nuttallii | Species of Concern | Wherever found | |
| Common Shiner | Luxilus cornutus | Not Listed | | |
| Common Snook | Centropomus undecimalis | Not Listed | | |
| Common Tern | Sterna hirundo | Species of Concern | Wherever found | |
| Common Wallowa paintbrush | Castilleja chrysantha | Resolved Taxon | Wherever found | |
| Common Yellowthroat | Geothlypis trichas sinuosa | Species of Concern | Wherever found | |
| Compact catseye | Cryptantha compacta | Resolved Taxon | Wherever found | |
| Compact cobweb thistle | Cirsium occidentale compactum | Species of Concern | Wherever found | |
| Compact elimia | Elimia showalteri | Not Listed | Wherever found | |
| Comstock's blue butterfly | Euphilotes battoides comstocki | Resolved Taxon | Wherever found | |
| Conasauga Blue burrower | Cambarus cymatilis | Status Undefined | Wherever found | |
| Conasauga logperch | Percina jenkinsi | Endangered | Wherever found | 08-05-1985 |
| Conchas crayfish | Orconectes deanae | Resolved Taxon | Wherever found | |
| Conchos pupfish | Cyprinodon eximius | Species of Concern | Wherever found | |
| Concho water snake | Nerodia paucimaculata | Recovery | Wherever found | 09-03-1986 |
| Conehead yellow-faced bee | Hylaeus coniceps | Species of Concern | Wherever found | |
| Conejo buckwheat | Eriogonum crocatum | Species of Concern | Wherever found | |
| Conejo dudleya | Dudleya abramsii ssp. parva | Threatened | Wherever found | 01-29-1997 |
| Cone Peak bedstraw | Galium californicum luciense | Species of Concern | Wherever found | |
| Confused helicoverpan noctuid moth | Helicoverpa confusa | Resolved Taxon | Wherever found | |
| Confusion caddisfly | Cryptochia shasta | Species of Concern | Wherever found | |
| Congdon's buckwheat | Eriogonum congdonii | Resolved Taxon | Wherever found | |
| Congdon's lewisia | Lewisia congdonii | Resolved Taxon | Wherever found | |
| Congdon's lomatium | Lomatium congdonii | Species of Concern | Wherever found | |
| Congdon's wooly-sunflower | Eriophyllum congdonii | Resolved Taxon | Wherever found | |
| Congo dwarf crocodile | Osteolaemus tetraspis osborni | Endangered | Wherever found | 06-14-1976 |
| Connected yellow-faced bee | Hylaeus connectens | Resolved Taxon | Wherever found | |
| Connecticut clam shrimp | Eulimnadia stoningtonensis | Species of Concern | Wherever found | |
| Connecticut Warbler | Oporornis agilis | Species of Concern | Wherever found | |
| Conservancy fairy shrimp | Branchinecta conservatio | Endangered | Wherever found | 09-19-1994 |
| Constance's bittercress | Cardamine constancei | Resolved Taxon | Wherever found | |
| Constance's rock-cress | Arabis constancei | Resolved Taxon | Wherever found | |
| Constricted elimia | Elimia impressa | Resolved Taxon | Wherever found | |
| Contact Mine streptanthus | Streptanthus brachiatus brachiatus | Species of Concern | Wherever found | |
| Contorted ochrotrichian micro caddisfly | Ochrotrichia contorta | Species of Concern | Wherever found | |
| Contra Costa buckwheat | Eriogonum truncatum | Resolved Taxon | Wherever found | |
| Contra Costa goldfields | Lasthenia conjugens | Endangered | Wherever found | 06-18-1997 |
| Contra Costa wallflower | Erysimum capitatum var. angustatum | Endangered | Wherever found | 05-27-1978 |
| Cookes' brown lacewing | Micromus cookeorum | Species of Concern | Wherever found | |
| Cooke's Peak woodlandsnail | Ashmunella macromphala | Under Review | Wherever found | |
| Cooke's phacelia | Phacelia cookei | Species of Concern | Wherever found | |
| Cook's anole | Ctenonotus cooki | Species of Concern | Wherever found | |
| Cook's holly | Ilex cookii | Endangered | Wherever found | 06-16-1987 |
| Cook's lomatium | Lomatium cookii | Endangered | Wherever found | 11-07-2002 |
| Cook's petrel | Pterodroma cookii | Resolved Taxon | Wherever found | |
| Cooley's meadowrue | Thalictrum cooleyi | Endangered | Wherever found | 02-07-1989 |
| Cooley's water-willow | Justicia cooleyi | Endangered | | 07-27-1989 |
| Cooper's cave amphipod | Stygobromus cooperi | Resolved Taxon | Wherever found | |
| Cooper's hawk | Accipiter cooperii | Species of Concern | Wherever found | |
| Cooper's rocky mountainsnail | Oreohelix strigosa cooperi | Resolved Taxon | Wherever found | |
| Coosa creekshell | Villosa umbrans | Under Review | Wherever found | |
| Coosa elktoe | Alasmidonta mccordi | Resolved Taxon | Wherever found | |
| Coosa moccasinshell | Medionidus parvulus | Endangered | Wherever found | 03-17-1993 |
| Coosa pebblesnail | Somatogyrus coosaensis | Species of Concern | Wherever found | |
| Coosa rocksnail | Leptoxis showalterii | Resolved Taxon | Wherever found | |
| Coosawattae crayfish | Cambarus coosawattae | Status Undefined | Wherever found | |
| Coot Bay dancing-lady | Oncidium carthagenense | Resolved Taxon | Wherever found | |
| Copeland's speedwell | Veronica copelandii | Resolved Taxon | Wherever found | |
| Copenhagen Basin pika | Ochotona princeps clamosa | Resolved Taxon | Wherever found | |
| Copepod | Acanthocyclops columbiensis | Resolved Taxon | Wherever found | |
| Copperbelly water snake | Nerodia erythrogaster neglecta | Threatened | Indiana north of 40 degrees north latitude, Michigan, Ohio | 01-29-1997 |
| Coppercheek darter | Etheostoma aquali | Species of Concern | Wherever found | |
| Coppermine milk-vetch | Astragalus cobrensis maguirei | Species of Concern | Wherever found | |
| Copris tortoise commensal scarab | Copris gopheri | Species of Concern | Wherever found | |
| Coral Beach Sand Dune weevil | Trigonoscuta dorothea corallana | Status Undefined | Wherever found | |
| Coral Pink Sand Dunes tiger beetle | Cicindela albissima | Resolved Taxon | Wherever found | |
| coral seeded popcornflower | Plagiobothrys figuratus ssp. corallicarpus | Species of Concern | Wherever found | |
| Cordilleran Flycatcher | Empidonax occidentalis | Species of Concern | | |
| Corkwood | Leitneria floridana | Species of Concern | Wherever found | |
| Corn Creek pyrg | Pyrgulopsis fausta | Resolved Taxon | Wherever found | |
| Coronado skink | Eumeces skiltonianus interparietalis | Species of Concern | Wherever found | |
| Corpulent hornsnail | Pleurocera corpulenta | Under Review | Wherever found | |
| Corpulent Rams Horn | Planorbella corpulenta | Not Listed | | |
| Correll's Bluet | Houstonia correllii | Resolved Taxon | Wherever found | |
| Correll''s false dragonhead | Physostegia correllii | Under Review | | |
| Correll's green pitaya | Echinocereus viridiflorus correllii | Resolved Taxon | Wherever found | |
| Corsican red deer | Cervus elaphus corsicanus | Endangered | Wherever found | 07-27-1979 |
| Corsican swallowtail butterfly | Papilio hospiton | Endangered | Wherever found | 01-14-1993 |
| Corymbed, Davidse wild-buckwheat | Eriogonum corymbosum davidsei | Resolved Taxon | Wherever found | |
| Corymbed, Reveal wild-buckwheat | Eriogonum corymbosum revealianum | Resolved Taxon | Wherever found | |
| Cory's Shearwater | Calonectris diomedea | Species of Concern | Wherever found | |
| Cossatot leaf-cup | Polymnia cossatotensis | Species of Concern | Wherever found | |
| Costa Rican jatropha | Jatropha costaricensis | Endangered | Wherever found | 07-27-1984 |
| Costa Rican puma | Puma (=Felis) concolor costaricensis | Endangered | Wherever found | 06-14-1976 |
| Costa's Hummingbird | Calypte costae | Species of Concern | Wherever found | |
| Cotorrilla | Heliotropium guanicense | Resolved Taxon | Wherever found | |
| Cottam milk-vetch | Astragalus cottamii | Resolved Taxon | Wherever found | |
| Cottonball Marsh Pupfish | Cyprinodon salinus milleri | Not Listed | | |
| Cotton's milk-vetch | Astragalus cottonii | Species of Concern | Wherever found | |
| Cotton-top tamarin | Saguinus oedipus | Endangered | Wherever found | 10-19-1976 |
| Cottonwood Spring suncup | Camissonia exilis | Resolved Taxon | Wherever found | |
| Cottony buckwheat | Eriogonum gossypinum | Resolved Taxon | Wherever found | |
| Couch's spadefoot toad | scaphiopus couchii | Species of Concern | Wherever found | |
| Coues' rice rat | Oryzomys couesi aquaticus | Species of Concern | Wherever found | |
| Coulter biscuitroot | Cymopterus coulteri | Resolved Taxon | Wherever found | |
| Coulter's matilija poppy | romneya coulteri | Species of Concern | Wherever found | |
| Coulter's saltbush | Atriplex coulteri | Species of Concern | Wherever found | |
| Cowan'S Amphipod | Stygobromus cowani | Not Listed | | |
| Cow Head tui chub | Siphateles bicolor vaccaceps | Resolved Taxon | Wherever found | |
| Cow Knob salamander | Plethodon punctatus | Resolved Taxon | Wherever found | |
| Cow-tongue prickly-pear | Opuntia lindheimeri linguiformis | Resolved Taxon | Wherever found | |
| Cox's dalea | Dalea bartonii | Resolved Taxon | Wherever found | |
| Cox's mariposa lily | Calochortus coxii | Species of Concern | Wherever found | |
| coyote | canis latrans | Species of Concern | Wherever found | |
| Coyote ceanothus | Ceanothus ferrisae | Endangered | Wherever found | 02-03-1995 |
| Coyote-thistle aster | Eurybia eryngiifolia | Species of Concern | Wherever found | |
| Crabronoid yellow-faced bee | Hylaeus crabronoides | Species of Concern | Wherever found | |
| Cracking pearlymussel | Hemistena lata | Endangered | Wherever found; Except where listed as Experimental Populations | 09-28-1989 |
| Cracking pearlymussel | Hemistena lata | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Cracking pearlymussel | Hemistena lata | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Craighead's nodding-caps | Triphora craigheadii | Species of Concern | Wherever found | |
| Crater Lake collomia | Collomia mazama | Species of Concern | Wherever found | |
| Crater Lake grap fern | Botrychium pumicola nealleyi | Species of Concern | Wherever found | |
| Crater Lake newt | Taricha granulosa mazamae | Under Review | | |
| Crater Lake tightcoil | Pristiloma arcticum ssp. crateris | Resolved Taxon | Wherever found | |
| Craveri's Murrelet | Synthliboramphus craveri | Species of Concern | | |
| Creamy tick-trefoil | Desmodium ochroleucum | Status Undefined | Wherever found | |
| Creek Chub | Semotilus atromaculatus | Not Listed | | |
| Creek Chubsucker | Erimyzon oblongus | Not Listed | | |
| Creek Heelsplitter | Lasmigona compressa | Not Listed | | |
| Creeper | Strophitus undulatus | Not Listed | | |
| Cremata agrotis noctuid moth | Agrotis cremata | Species of Concern | Wherever found | |
| Crenulate lead-plant | Amorpha crenulata | Endangered | | 07-18-1985 |
| Crescent Dune aegialian scarab | Aegialia crescenta | Resolved Taxon | Wherever found | |
| Crescent Dune aphodius scarab | Aphodius sp. | Species of Concern | Crescent Dune | |
| Crescent Dunes serican scarab | Serica ammomensico | Resolved Taxon | Crescent Dune | |
| Crescent nail-tailed wallaby | Onychogalea lunata | Endangered | Wherever found | 12-02-1970 |
| Crescent Shiner | Luxilus cerasinus | Not Listed | | |
| Crested auklet | Aethia cristatella | Not Listed | | |
| Crested caracara (Audubon''''s) [FL DPS] | Caracara plancus audubonii | Threatened | U.S.A. (FL) | 07-06-1987 |
| Crested Riverlet crayfish | Hobbseus cristatus | Under Review | Wherever found | |
| Crimson Hawaiian damselfly | Megalagrion leptodemas | Endangered | Wherever found | 10-18-2012 |
| Crimson shining parrot | Prosopeia splendens | Under Review | Wherever found | |
| Crisp monardella | Monardella crispa | Species of Concern | Wherever found | |
| Crissal thrasher | toxostoma crissale | Species of Concern | Wherever found | |
| Croatan crayfish | Procambarus plumimanus | Species of Concern | Wherever found | |
| Crocker's draba | Draba douglasii crockeri | Resolved Taxon | Wherever found | |
| Cronquist daisy | Erigeron cronquistii | Species of Concern | Wherever found | |
| Cronquist milk-vetch | Astragalus cronquistii | Species of Concern | Wherever found | |
| Cronquist's stickseed | Hackelia cronquistii | Species of Concern | Wherever found | |
| Cronquist wild-buckwheat | Eriogonum cronquistii | Resolved Taxon | Wherever found | |
| Crosby's buckwheat | Eriogonum crosbyae | Resolved Taxon | Wherever found | |
| Crossroads cave beetle | Pseudanophthalmus intersectus | Not Listed | Wherever found | |
| Crotch bumble bee | Bombus crotchii | Not Listed | | |
| Crown darter | Etheostoma corona | Species of Concern | Wherever found | |
| Crowned muilla | Muilla coronata | Resolved Taxon | Wherever found | |
| Cruise's golden aster | Chrysopsis gossypina cruiseana | Species of Concern | Wherever found | |
| Crystal Caverns cave spider | Nesticus furtivus | Species of Concern | Wherever found | |
| Crystal darter | Crystallaria asprella | Resolved Taxon | Wherever found | |
| Crystal siltsnail | Cincinnatia helicogyra | Species of Concern | Wherever found | |
| Crystal springsnail | Pyrgulopsis crystalis | Resolved Taxon | Wherever found | |
| Cuatro Cienegas softshell turtle | Trionyx ater | Endangered | Wherever found | 06-14-1976 |
| Cuba hook-billed kite | Chondrohierax uncinatus wilsonii | Endangered | Wherever found | 06-02-1970 |
| Cuban crocodile | Crocodylus rhombifer | Endangered | Wherever found | 06-02-1970 |
| Cuban Greater Funnel-Eared Bat | Natalus primus | Under Review | Wherever found | |
| Cuban ground iguana | Cyclura nubila nubila | Threatened | Cuba (excludes U.S. Puerto Rico population) | 06-22-1983 |
| Cuban solenodon | Solenodon cubanus | Endangered | Wherever found | 06-02-1970 |
| Cuba sandhill crane | Grus canadensis nesiotes | Endangered | Wherever found | 06-14-1976 |
| Cudjo's cave beetle | Pseudanophthalmus hirsutus | Not Listed | Wherever found | |
| Cuero de sapo | Maytenus elongata | Species of Concern | Wherever found | |
| Cuero de sapo | Maytenus ponceana | Resolved Taxon | Wherever found | |
| Cuesta Pass sidalcea | Sidalcea hickmanii anomala | Species of Concern | Wherever found | |
| Cui-ui | Chasmistes cujus | Endangered | Wherever found | 03-11-1967 |
| Culbertson's paintbrush | Castilleja lemmonii | Resolved Taxon | Wherever found | |
| Culebra garden snake | Arrhyton exiguum exiguum | Species of Concern | Wherever found | |
| Culebra Island giant anole | Anolis roosevelti | Endangered | Wherever found | 08-22-1977 |
| Culebra Skink | Spondylurus culebrae | Proposed Threatened | Wherever found | |
| Culver's cave amphipod | Stygobromus culveri | Species of Concern | Wherever found | |
| Culver's planarian | Sphalloplana culveri | Species of Concern | Wherever found | |
| Cumberland arrow darter | Etheostoma sagitta | Resolved Taxon | Wherever found | |
| Cumberland bean (pearlymussel) | Villosa trabalis | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Cumberland bean (pearlymussel) | Villosa trabalis | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Cumberland bean (pearlymussel) | Villosa trabalis | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Cumberland darter | Etheostoma susanae | Endangered | Wherever found | 09-08-2011 |
| Cumberland Dusky salamander | Desmognathus abditus | Under Review | Wherever found | |
| Cumberland elktoe | Alasmidonta atropurpurea | Endangered | Wherever found | 01-10-1997 |
| Cumberlandian combshell | Epioblasma brevidens | Endangered | Wherever found; Except where listed as Experimental Populations | 01-10-1997 |
| Cumberlandian combshell | Epioblasma brevidens | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Cumberlandian combshell | Epioblasma brevidens | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Cumberland leafshell | Epioblasma stewardsonii | Resolved Taxon | Wherever found | |
| Cumberland moccasinshell | Medionidus conradicus | Proposed Endangered | Wherever found | |
| Cumberland monkeyface (pearlymussel) | Theliderma intermedia | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Cumberland monkeyface (pearlymussel) | Theliderma intermedia | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Cumberland monkeyface (pearlymussel) | Theliderma intermedia | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Cumberland papershell | Anodontoides denigrata | Species of Concern | Wherever found | |
| Cumberland pigtoe | Pleuronaia gibber | Endangered | Wherever found | 05-07-1991 |
| Cumberland pocket gopher | Geomys cumberlandius | Species of Concern | Wherever found | |
| Cumberland rosemary | Conradina verticillata | Threatened | Wherever found | 11-29-1991 |
| Cumberland sandreed | Calamovilfa arcuata | Status Undefined | | |
| Cumberland sandwort | Arenaria cumberlandensis | Recovery | Wherever found | 06-23-1988 |
| Cuneate bidens | Bidens cuneata | Original Data in Error - Taxonomic Revision | Wherever found | 02-17-1984 |
| Cup Lake draba | Draba asterophora macrocarpa | Species of Concern | Wherever found | |
| Curly-grass fern | Actinostachys pennula | Resolved Taxon | Wherever found | |
| Curly-grass fern | Schizaea pusilla | Resolved Taxon | Wherever found | |
| Curro's Amphipod | Stygobromus curroae | Resolved Taxon | Wherever found | |
| Curtis Pearlymussel | Epioblasma curtisii | Endangered | Wherever found | 06-14-1976 |
| Curtiss' loosestrife | Lythrum curtissii | Under Review | Wherever found | |
| Curve-billed Thrasher | Toxostoma curvirostre | Species of Concern | Wherever found | |
| Curved-foot hygrotus diving beetle | Hygrotus curvipes | Species of Concern | Wherever found | |
| Curve-podded Mojave milk-vetch | Astragalus mohavensis hemigyrus | Species of Concern | Wherever found | |
| Cushenbury buckwheat | Eriogonum ovalifolium var. vineum | Endangered | Wherever found | 08-24-1994 |
| Cushenbury milk-vetch | Astragalus albens | Endangered | Wherever found | 08-24-1994 |
| Cushenbury oxytheca | Oxytheca parishii var. goodmaniana | Endangered | Wherever found | 08-24-1994 |
| Cushion Bladderpod | Physaria pulvinata | Resolved Taxon | Wherever found | |
| Cusick's buckwheat | Eriogonum cusickii | Species of Concern | Wherever found | |
| Cusick's lupine | Lupinus cusickii | Species of Concern | Wherever found | |
| Cuthbert's turtlehead | chelone cuthbertii | Species of Concern | Wherever found | |
| Cutler milkweed | Asclepias cutleri | Resolved Taxon | Wherever found | |
| Cutler's spurred lupine | Lupinus caudatus ssp. cutleri | Resolved Taxon | Wherever found | |
| Cutler's twistflower | Streptanthus cutleri | Species of Concern | Wherever found | |
| Cutthroat grass | Panicum abscissum | Species of Concern | Wherever found | |
| Cuyamaca cypress | Callitropsis stephensonii | Resolved Taxon | Wherever found | |
| Cuyamaca gumplant | Grindelia hirsutula | Resolved Taxon | Wherever found | |
| Cuyamaca larkspur | Delphinium hesperium cuyamacae | Species of Concern | Wherever found | |
| Cuyamaca raspberry | Rubus glaucifolius ganderi | Species of Concern | Wherever found | |
| Cuyamac Lake downingia | Downingia concolor brevior | Resolved Taxon | Wherever found | |
| Cylinder elimia | Elimia cylindracea | Status Undefined | Wherever found | |
| Cylinder spikerush | Eleocharis cylindrica | Resolved Taxon | Wherever found | |
| Cylindrical lioplax (snail) | Lioplax cyclostomaformis | Endangered | Wherever found | 10-28-1998 |
| Cylindrical Papershell | Anodontoides ferussacianus | Not Listed | | |
| Cylindrical Vertigo | Vertigo binneyana | Resolved Taxon | Wherever found | |
| Cypress crayfish | Cambarellus blacki | Under Review | Wherever found | |
| Cypress Darter | Etheostoma proeliare | Not Listed | | |
| Cypress Minnow | Hybognathus hayi | Not Listed | | |
| Dacite manzanita | Arctostaphylos tomentosa daciticola | Species of Concern | Wherever found | |
| Daecke's pyralid moth | Crambus daeckeellus | Species of Concern | Wherever found | |
| Daggernose Shark | Isogomphodon oxyrhynchus | Endangered | | |
| Daggett, rock-cress | Arabis demissa languida | Resolved Taxon | Wherever found | |
| Daggett, rock-cress | Arabis demissa russeola | Resolved Taxon | Wherever found | |
| Dakota Skipper | Hesperia dacotae | Threatened | Wherever found | 11-24-2014 |
| Dalles sideband | Monadenia fidelis minor | Resolved Taxon | Wherever found | |
| Dama gazelle | Gazella dama | Endangered | Wherever found | 09-02-2005 |
| Dappled mountain robin | Arcanator orostruthus | Threatened | Wherever found | 01-12-1995 |
| Dark blue | Euphilotes enoptes ssp. | Species of Concern | Wherever found | |
| Dark pigtoe | Pleurobema furvum | Endangered | Wherever found | 03-17-1993 |
| Dark-sided salamander | Eurycea aquatica | Species of Concern | Wherever found | |
| Darkwing yellow-faced bee | Hylaeus fuscipennis | Species of Concern | Wherever found | |
| Darlington's spurge | Euphorbia purpurea | Species of Concern | Wherever found | |
| Darrov's wild-buckwheat | Eriogonum darrovii | Resolved Taxon | Wherever found | |
| Davidson's bush-mallow | Malacothamnus davidsonii | Species of Concern | Wherever found | |
| Davidson's saltscale | atriplex serenana var. davidsonii | Species of Concern | Wherever found | |
| Davidson's stonecrop | Sedum niveum | Resolved Taxon | Wherever found | |
| Davis County springsnail | Fontelicella davisi | Species of Concern | Wherever found | |
| Davis' green pitaya | Echinocereus viridiflorus var. davisii | Endangered | Wherever found | 12-08-1979 |
| Davis Mountains cottontail rabbit | Sylvilagus floridanus robustus | Species of Concern | Wherever found | |
| Davis' pepper cress | Lepidium davisii | Species of Concern | Wherever found | |
| Davis' stickseed | Hackelia davisii | Resolved Taxon | Wherever found | |
| Day gecko | Phelsuma edwardnewtoni | Endangered | Wherever found | 06-02-1970 |
| Day Valley desert-parsley | Lomatium minus | Resolved Taxon | Wherever found | |
| Deane's milk-vetch | Astragalus deanei | Species of Concern | Wherever found | |
| Dearolf's cave amphipod | Crangonyx dearolfi | Species of Concern | Wherever found | |
| Death eopenthes click beetle | Eopenthes funebris | Species of Concern | Wherever found | |
| Death Valley agabus diving beetle | Agabus rumppi | Resolved Taxon | Wherever found | |
| Death Valley Amphipod | Hyalella sandra | Not Listed | | |
| Death Valley june beetle | Polyphylla erratica | Species of Concern | Wherever found | |
| Death Valley monkeyflower | Mimulus rupicola | Resolved Taxon | Wherever found | |
| Death Valley sage | Salvia funerea | Resolved Taxon | Wherever found | |
| Death Valley sandpaperplant | Petalonyx thurberi gilmanii | Species of Concern | Wherever found | |
| Debeque milk-vetch | Astragalus debequaeus | Resolved Taxon | Wherever found | |
| DeBeque phacelia | Phacelia submutica | Threatened | Wherever found | 08-26-2011 |
| Debris milk-vetch | Astragalus detritalis | Resolved Taxon | Wherever found | |
| Deceptive cave beetle | Pseudanophthalmus deceptivus | Species of Concern | Wherever found | |
| Deceptive eopenthes click beetle | Eopenthes deceptor | Species of Concern | Wherever found | |
| Decodon borer moth | Papaipema sulphurata | Species of Concern | Wherever found | |
| Decurrent false aster | Boltonia decurrens | Threatened | Wherever found | 11-14-1988 |
| DeDecker's clover | Trifolium dedeckerae | Resolved Taxon | Wherever found | |
| DeDecker's lupine | Lupinus padre-crowleyi | Species of Concern | Wherever found | |
| Deep Burrowing Mayfly | Hexagenia bilineata | Not Listed | | |
| Deepwater cisco | Coregonus johannae | Resolved Taxon | Wherever found | |
| Deepwater Sculpin | Myoxocephalus thompsonii | Not Listed | | |
| Deertoe | Truncilla truncata | Not Listed | | |
| Degener beardtongue | Penstemon degeneri | Resolved Taxon | Wherever found | |
| Dehesa beargrass | Nolina interrata | Resolved Taxon | Wherever found | |
| Delaware County Cave Crayfish | Cambarus subterraneus | Under Review | Wherever found | |
| Delhi Sands flower-loving fly | Rhaphiomidas terminatus abdominalis | Endangered | Wherever found | 09-23-1993 |
| Delicate spike | Elliptio arctata | Under Review | Wherever found | |
| Delicate Vertigo | Vertigo bollesiana | Not Listed | | |
| Del Mar manzanita | Arctostaphylos glandulosa ssp. crassifolia | Endangered | Wherever found | 10-07-1996 |
| Del Mar sand aster | Corethrogyne filaginifolia linifolia | Resolved Taxon | Wherever found | |
| Delmarva Peninsula fox squirrel | Sciurus niger cinereus | Recovery | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Delmarva Peninsula fox squirrel | Sciurus niger cinereus | Resolved Taxon | U.S.A. (DE, Sussex Co.) | 09-13-1984 |
| Del Norte checkermallow | Sidalcea malviflora elegans | Resolved Taxon | Wherever found | |
| Del Norte fleabane | Erigeron cervinus | Resolved Taxon | Wherever found | |
| Del Norte manzanita | Arctostaphylos nortensis | Species of Concern | Wherever found | |
| Del Norte salamander | Plethodon elongatus | Species of Concern | Wherever found | |
| Delong's mixogaster flower fly | Mixogaster delongi | Species of Concern | Wherever found | |
| Delta coyote-thistle | Eryngium racemosum | Species of Concern | Wherever found | |
| Delta green ground beetle | Elaphrus viridis | Threatened | Wherever found | 08-08-1980 |
| Delta Hydrobe | Probythinella emarginata | Not Listed | | |
| Delta june beetle | Polyphylla stellata | Species of Concern | Wherever found | |
| Delta smelt | Hypomesus transpacificus | Threatened | Wherever found | 03-05-1993 |
| Delta tule-pea | Lathyrus jepsonii jepsonii | Species of Concern | Wherever found | |
| Deltoid spurge | Chamaesyce deltoidea ssp. deltoidea | Endangered | | 07-18-1985 |
| Denning's agapetus caddisfly | Agapetus denningi | Species of Concern | Wherever found | |
| Denning's cryptic caddisfly | Cryptochia denningi | Species of Concern | Wherever found | |
| Dense hydrobe | Aphaostracon pycnum | Status Undefined | Wherever found | |
| Dense reedgrass | Calamagrostis koelerioides | Resolved Taxon | Wherever found | |
| Dense twinpod | Physaria condensata | Resolved Taxon | Wherever found | |
| Dented Peninsula snail | Helminthoglypta arrosa miwoka | Resolved Taxon | Wherever found | |
| Depauperate daisy | Erigeron mancus | Species of Concern | Wherever found | |
| Descanso milk-vetch | Astragalus oocarpus | Species of Concern | Wherever found | |
| Deschutes ochrotrichian micro caddisfly | Ochrotrichia phenosa | Species of Concern | Wherever found | |
| Deseret milkvetch | Astragalus desereticus | Recovery | Wherever found | 10-20-1999 |
| Desert bandicoot | Perameles eremiana | Endangered | Wherever found | 06-04-1973 |
| Desert beauty | Linanthus bellus | Resolved Taxon | Wherever found | |
| Desert birds-beak | Cordylanthus eremicus eremicus | Resolved Taxon | Wherever found | |
| Desert christmas tree | Pholisma arenarium | Resolved Taxon | Wherever found | |
| Desert cymopterus | Cymopterus deserticola | Resolved Taxon | Wherever found | |
| Desert dace | Eremichthys acros | Threatened | Wherever found | 03-11-1967 |
| Desert iguana | dipsosaurus dorsalis | Species of Concern | Wherever found | |
| Desert king snake | Lampropeltis getula splendida | Resolved Taxon | Wherever found | |
| Desert massasauga | Sistrurus catenatus ssp. edwardsii | Not Listed | Wherever found | |
| Desert monitor | Varanus griseus | Endangered | Wherever found | 06-14-1976 |
| Desert monkey grasshopper | Psychomastix deserticola | Species of Concern | Wherever found | |
| Desert night-blooming cereus | Peniocereus greggii greggii | Species of Concern | Wherever found | |
| Desert (=plain) rat-kangaroo | Caloprymnus campestris | Endangered | Wherever found | 12-02-1970 |
| Desert pocket gopher | Geomys bursarius arenarius | Species of Concern | Wherever found | |
| Desert pupfish | Cyprinodon macularius | Endangered | Wherever found | 03-31-1986 |
| Desert sage | Salvia eremostachya | Resolved Taxon | Wherever found | |
| Desert slender salamander | Batrachoseps aridus | Endangered | Wherever found | 06-04-1973 |
| Desert springsnail snail | Pyrgulopsis deserta | Resolved Taxon | Wherever found | |
| Desert sucker | Pantosteus clarkii | Species of Concern | Desert | |
| Desert tansyaster | Arida arizonica | Resolved Taxon | Wherever found | |
| Desert tortoise | Gopherus agassizii | Similarity of Appearance (Threatened) | AZ south and east of Colorado R., and Mexico, when found outside of Mexico or said range in AZ | 04-02-1990 |
| Desert tortoise | Gopherus agassizii | Threatened | Wherever found, except AZ south and east of Colorado R., and Mexico | 04-02-1990 |
| Desert Valley kangaroo mouse | Microdipodops megacephalus albiventer | Species of Concern | Wherever found | |
| Desert wild-buckwheat | Eriogonum deserticola | Resolved Taxon | Wherever found | |
| Desert yellowhead | Yermo xanthocephalus | Threatened | Wherever found | 03-14-2002 |
| Desmarest's fig-eating bat | Stenoderma rufum | Species of Concern | Wherever found | |
| Destruction Island shrew | Sorex trowbridgii destructioni | Species of Concern | Wherever found | |
| Devils Hole pupfish | Cyprinodon diabolis | Endangered | Wherever found | 03-11-1967 |
| Devil's Hole warm spring riffle beetle | Stenelmis calida calida | Resolved Taxon | Wherever found | |
| Devils River minnow | Dionda diaboli | Threatened | Wherever found | 10-20-1999 |
| Devil's Sinkhole amphipod | Stygobromus hadenoecus | Resolved Taxon | Wherever found | |
| devil tryonia | Tryonia diaboli | Resolved Taxon | Wherever found | |
| Dhole | Cuon alpinus | Endangered | Wherever found | 06-02-1970 |
| Diablo Mountainsnail | Oreohelix houghi | Resolved Taxon | Wherever found | |
| Diablo rock-rose | Helianthella castanea | Species of Concern | Wherever found | |
| Diamondback terrapin | Malaclemys terrapin | Status Undefined | | |
| diamond Darter | Crystallaria cincotta | Endangered | Wherever found | 08-26-2013 |
| Diamond Head nesosydne planthopper | Nesosydne leahi | Species of Concern | Wherever found | |
| Diamond Head schiedea | Schiedea adamantis | Endangered | Wherever found | 02-17-1984 |
| Diamond Lake mission-bells | Fritillaria atropurpurea | Resolved Taxon | Wherever found | |
| Diamond-petaled poppy | Eschscholzia rhombipetala | Species of Concern | Wherever found | |
| Diamond Tryonia | Pseudotryonia adamantina | Endangered | Wherever found | 07-09-2013 |
| Diamond Valley speckled dace | Rhinichthys osculus ssp. | Species of Concern | Diamond Valley | |
| Diamond Valley suncup | Camissonia gouldii | Resolved Taxon | Wherever found | |
| Diamond-Y pond snail | Physella bottimeri | Resolved Taxon | Wherever found | |
| Diana fritillary | Speyeria diana | Species of Concern | Wherever found | |
| Diana monkey | Cercopithecus diana | Endangered | Wherever found | 10-19-1976 |
| Dibbler | Antechinus apicalis | Endangered | Wherever found | 12-02-1970 |
| Dickcissel | Spiza americana | Species of Concern | Wherever found | |
| Dicranoweisia moss | dicranoweisia crispula | Species of Concern | Wherever found | |
| Difficult yellow-faced bee | Hylaeus difficilis | Species of Concern | Wherever found | |
| Dimidiatan yellow-faced bee | Hylaeus dimidiatus | Species of Concern | Wherever found | |
| Diminuitive Pebblesnail | Fluminicola sp | Resolved Taxon | Wherever found | |
| Diminutive Amphipod | Gammarus hyalelloides | Not Listed | | |
| Diminutive Amphipod | Gammarus hyalleloides | Endangered | Wherever found | 07-09-2013 |
| Dimmit sunflower | Helianthus praecox hirtus | Species of Concern | Wherever found | |
| Dimorphic snapdragon | Sairocarpus subcordatus | Resolved Taxon | Wherever found | |
| Dinosaur milk-vetch | Astragalus saurinus | Resolved Taxon | Wherever found | |
| Dinosaur wild-buckwheat | Eriogonum lonchophyllum saurinum | Resolved Taxon | Wherever found | |
| disciplina | lycopodium phlegmaria var. | Species of Concern | Wherever found | |
| Disjunct crawling water beetle | Haliplus nitens | Species of Concern | Wherever found | |
| Dismal Swamp chlorochroan bug | Chlorochroa dismalia | Species of Concern | Wherever found | |
| Dismal Swamp short-tailed shrew | Blarina brevicauda telmalestes | Resolved Taxon | Wherever found | |
| Dismal Swamp southeastern shrew | Sorex longirostris fisheri | Original Data in Error - New Information Discovered | Wherever found | 09-26-1986 |
| Dismal Swamp (=southern bog) lemming | Synaptomys cooperi helaletes | Resolved Taxon | Wherever found | |
| Distal-gland springsnail | Pyrgulopsis nanus | Resolved Taxon | Wherever found | |
| Diverse isonychian mayfly | Isonychia diversa | Resolved Taxon | Wherever found | |
| Dixie Valley Toad | Anaxyrus williamsi | Endangered | | 12-02-2022 |
| Dixie Valley tui chub | Siphateles bicolor ssp. 9 | Species of Concern | Dixie Valley | |
| Djibouti francolin | Francolinus ochropectus | Endangered | Wherever found | 01-12-1995 |
| Dog Valley ivesia | Ivesia aperta canina | Species of Concern | Wherever found | |
| Dohrn's elegant eucnemid beetle | Paleoxenus dohrni | Species of Concern | Wherever found | |
| dolan falls salamander | eurycea species | Resolved Taxon | Wherever found | |
| Dolan Falls salamander | eurycea speciesten | Resolved Taxon | Wherever found | |
| Dollar orchid | Encyclia boothiana erythronioides | Resolved Taxon | Wherever found | |
| Dolloff Cave spider | Meta dollof | Resolved Taxon | Wherever found | |
| Doll's daisy | Boltonia montana | Resolved Taxon | | |
| Doll's merolonche | Merolonche dolli | Species of Concern | Wherever found | |
| Dolly Varden | Salvelinus malma | Proposed Similarity of Appearance (Threatened) | Wherever found | |
| Dolomite draba | Draba crassifolia nevadensis | Species of Concern | Wherever found | |
| Dolores desert pink | Lygodesmia doloresensis | Resolved Taxon | Wherever found | |
| Dolphin and Union caribou | Rangifer tarandus ssp. groenlandicus x pearyi | Endangered | Wherever found | 01-12-2023 |
| Dolphin Island kangaroo rat | Dipodomys microps russeolus | Species of Concern | Wherever found | |
| Dolphin Island ord's kangaroo rat | Dipodomys ordii cineraceus | Species of Concern | Wherever found | |
| Domed ancylid | Rhodacme elatior | Under Review | Wherever found | |
| Dona Ana talussnail | Sonorella todseni | Under Review | Wherever found | |
| Donner Pass buckwheat | Eriogonum umbellatum torreyanum | Species of Concern | Wherever found | |
| Donner und Blitzen pebblesnail | Fluminicola insolitus | Not Listed | | |
| Dorothy's El Segundo Dune weevil | Trigonoscuta dorothea dorothea | Species of Concern | Wherever found | |
| Dorr's Cabin jewelflower | Streptanthus morrisonii hirtiflorus | Species of Concern | Wherever found | |
| Double-crested Cormorant | phalacrocorax auritus | Species of Concern | Wherever found | |
| Doubtful Canyon Talussnail | Sonorella waltoni | Resolved Taxon | Wherever found | |
| Douc langur | Pygathrix nemaeus | Endangered | Wherever found | 06-02-1970 |
| Doudoroff's elfin butterfly | Incisalia mossi windi | Resolved Taxon | Wherever found | |
| Dougherty Plain Cave crayfish | Cambarus cryptodytes | Status Undefined | Wherever found | |
| Douglas County pocket gopher | Thomomys talpoides macrotis | Resolved Taxon | Wherever found | |
| Douglas' draba | Draba douglasii douglasii | Resolved Taxon | Wherever found | |
| Douglas stenelmis riffle beetle | Stenelmis douglasensis | Species of Concern | Wherever found | |
| Dovekie | Alle alle | Resolved Taxon | Wherever found | |
| Downy woodpecker | picoides pubescens | Species of Concern | Wherever found | |
| Doyen's trigonoscuta dune weevil | Trigonoscuta sp. | Species of Concern | Wherever found | |
| Drab phacelia | Phacelia indecora | Resolved Taxon | Wherever found | |
| Dragoon Talussnail | Sonorella ferrissi | Resolved Taxon | Wherever found | |
| Drill | Mandrillus (=Papio) leucophaeus | Endangered | Wherever found | 10-19-1976 |
| Dromedary pearlymussel | Dromus dromas | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Dromedary pearlymussel | Dromus dromas | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Dromedary pearlymussel | Dromus dromas | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Drummond bluebell | Mertensia drummondii | Species of Concern | Wherever found | |
| Drummond mountainsnail | Oreohelix spfour | Resolved Taxon | Wherever found | |
| Drummond mountain snail | Oreohelix speciesfour | Under Review | Wherever found | |
| Drummond's yellow-eyed grass | Xyris drummondii | Species of Concern | Wherever found | |
| Dry Creek cliff strider bug | Oravelia pege | Species of Concern | Wherever found | |
| Dry Fork Valley cave beetle | Pseudanophthalmus montanus | Under Review | Wherever found | |
| Dry Fork Valley cave pseudoscorpion | Apochthonius paucispinosus | Species of Concern | Wherever found | |
| Drymaria dwarf-flax | Hesperolinon drymarioides | Species of Concern | Wherever found | |
| Dubakella Mountain buckwheat | Eriogonum libertini | Resolved Taxon | Wherever found | |
| Dubiraphian riffle beetle | Dubiraphia sp. | Resolved Taxon | Wherever found | |
| Duchesne biscuitroot | Cymopterus duchesnensis | Resolved Taxon | Wherever found | |
| Duchesne milk-vetch | Astragalus duchesnensis | Resolved Taxon | Wherever found | |
| Duchesne River Twinpod | Physaria stylosa | Resolved Taxon | Wherever found | |
| Duck River bladder-pod | Lesquerella densipila | Resolved Taxon | Wherever found | |
| Duck River cave beetle | Pseudanophthalmus tullahoma | Resolved Taxon | Wherever found | |
| Duck River Dartersnapper | Epioblasma ahlstedti | Not Listed | | |
| Duckwater frog | Rana | Resolved Taxon | Wherever found | |
| Duckwater pyrg | Pyrgulopsis aloba | Resolved Taxon | Wherever found | |
| Duckwater Warm Springs pyrg | Pyrgulopsis villacampae | Resolved Taxon | Wherever found | |
| Dudley Bluffs bladderpod | Lesquerella congesta | Threatened | Wherever found | 02-06-1990 |
| Dudley Bluffs twinpod | Physaria obcordata | Threatened | Wherever found | 02-06-1990 |
| Dudley's brodiaea | Triteleia dudleyi | Resolved Taxon | Wherever found | |
| Dudley's lousewort | Pedicularis dudleyi | Species of Concern | Wherever found | |
| Dudley's swordfern | Polystichum dudleyi | Resolved Taxon | Wherever found | |
| Dugong | Dugong dugon | Endangered | Wherever found | 12-02-1970 |
| Dukes' skipper | Euphyes dukesi calhouni | Under Review | Wherever found | |
| Dulzura California pocket mouse | Perognathus californicus femoralis | Species of Concern | Wherever found | |
| Dulzura kangaroo rat | dipodomys simulans | Species of Concern | Wherever found | |
| Duncan's cory cactus | Coryphantha duncanii | Species of Concern | Wherever found | |
| Dune larkspur | Delphinium parryi blochmaniae | Species of Concern | Wherever found | |
| Dunes sagebrush lizard | Sceloporus arenicolus | Endangered | Wherever found | 06-20-2024 |
| Dune tansy | Tanacetum camphoratum | Resolved Taxon | Wherever found | |
| Dune unicorn plant | Proboscidea sabulosa | Resolved Taxon | Wherever found | |
| Dungeness Crab | Cancer magister | Not Listed | | |
| Dunn's mariposa lily | Calochortus dunnii | Species of Concern | Wherever found | |
| Dunn's salamander | plethodon dunni | Species of Concern | Wherever found | |
| Dun skipper | Euphyes vestris harbisoni | Resolved Taxon | Wherever found | |
| Duran's alumroot | Heuchera duranii | Resolved Taxon | Wherever found | |
| Dusky crawfish frog | Rana areolata sevosa | Species of Concern | Wherever found | |
| dusky gopher frog | Rana sevosa | Endangered | Wherever found | 12-04-2001 |
| Dusky Mantleslug | Philomycus batchi | Resolved Taxon | Wherever found | |
| Dusky seaside sparrow | Ammodramus maritimus nigrescens | Extinction | Wherever found | 03-11-1967 |
| Dusky sea snake | Aipysurus fuscus | Endangered | | 11-06-2015 |
| Duskytail darter | Etheostoma percnurum | Endangered | Wherever found | 04-27-1993 |
| Duskytail darter | Etheostoma percnurum | Experimental Population, Non-Essential | The Tellico River, between the backwaters of the Tellico Reservoir (approximately Tellico River mile 19 (30.4 kilometers) and Tellico River mile 33 (52.8 kilometers), near the Tellico Ranger Station, Monroe County, Tennessee. | 08-12-2002 |
| Duskytail darter | Etheostoma percnurum | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.84(q)(1)(ii)) | 10-15-2007 |
| Dwarf Bear-poppy | Arctomecon humilis | Endangered | Wherever found | 12-06-1979 |
| Dwarf checkerbloom | Sidalcea malviflora ssp. virgata | Species of Concern | Wherever found | |
| Dwarf downingia | Downingia pusilla | Resolved Taxon | Wherever found | |
| Dwarf-flowered heartleaf | Hexastylis naniflora | Threatened | Wherever found | 04-14-1989 |
| Dwarf goldenstar | Bloomeria humilis | Species of Concern | Wherever found | |
| Dwarf hutia | Capromys nana | Endangered | Wherever found | 05-16-1986 |
| Dwarf iliau | Wilkesia hobdyi | Endangered | Wherever found | 06-22-1992 |
| Dwarf lake iris | Iris lacustris | Threatened | Wherever found | 09-28-1988 |
| Dwarf meadowfoam | Limnanthes floccosa ssp. pumila | Species of Concern | Wherever found | |
| Dwarf naupaka | Scaevola coriacea | Endangered | Wherever found | 05-16-1986 |
| Dwarf pebblesnail | Somatogyrus nanus | Species of Concern | Wherever found | |
| Dwarf polypody | Grammitis nimbata | Species of Concern | Wherever found | |
| Dwarf rainbow | Leaunio pataecus | Not Listed | | |
| Dwarf sawfish | Pristis clavata | Endangered | Wherever found | 01-12-2015 |
| Dwarf Seahorse | Hippocampus zosterae | Not Listed | | |
| Dwarf Sturgeon | Pseudoscaphirhynchus hermanni | Under Review | Wherever found | |
| Dwarf wedgemussel | Alasmidonta heterodon | Endangered | Wherever found | 03-14-1990 |
| Dwarf wild-buckwheat | Eriogonum nanum | Resolved Taxon | Wherever found | |
| Dwarf witch-alder | Fothergilla gardenii | Resolved Taxon | Wherever found | |
| Eagle Lake rainbow Trout | Oncorhynchus mykiss aquilarum | Resolved Taxon | Wherever found | |
| Eagle Mountain scrub jay | Aphelocoma coerulescens cana | Species of Concern | Wherever found | |
| Eared coneflower | Rudbeckia auriculata | Under Review | Wherever found | |
| Eared Grebe | Podiceps nigricollis | Species of Concern | Wherever found | |
| Earthquake Merriam's kangaroo rat | Dipodomys merriami collinus | Species of Concern | Wherever found | |
| East Bay clarkia | Clarkia concinna automixa | Species of Concern | Wherever found | |
| Eastern beard grass Skipper | Atrytone arogos arogos | Species of Concern | Wherever found | |
| Eastern Bewick''s Wren | Thryomanes bewickii ssp. bewickii | Species of Concern | Wherever found | |
| Eastern Black rail | Laterallus jamaicensis ssp. jamaicensis | Threatened | Wherever found | 11-09-2020 |
| Eastern Bluebird | Sialia sialis | Not Listed | | |
| Eastern Box Turtle | Terrapene carolina carolina | Not Listed | | |
| Eastern cottontail rabbit | Sylvilagus floridanus mearnsi | Resolved Taxon | Wherever found | |
| Eastern Creekshell | Villosa delumbis | Not Listed | | |
| Eastern diamondback rattlesnake | Crotalus adamanteus | Under Review | Wherever found | |
| Eastern Elliptio | Elliptio complanata | Not Listed | | |
| Eastern Floater | Pyganodon cataracta | Not Listed | | |
| Eastern gray kangaroo | Macropus giganteus | Recovery | Wherever found | 12-30-1974 |
| Eastern Hellbender | Cryptobranchus alleganiensis alleganiensis | Endangered | Missouri DPS | 04-07-2021 |
| Eastern Hellbender | Cryptobranchus alleganiensis alleganiensis | Proposed Endangered | Wherever found | |
| Eastern indigo snake | Drymarchon couperi | Threatened | Wherever found | 03-03-1978 |
| Eastern jerboa marsupial | Antechinomys laniger | Endangered | Wherever found | 12-02-1970 |
| Eastern Joshua tree | Yucca jaegeriana | Not Listed | | |
| Eastern Kingbird | Tyrannus tyrannus | Species of Concern | Wherever found | |
| Eastern Lampmussel | Lampsilis radiata | Not Listed | | |
| Eastern marten | Martes americana americana | Resolved Taxon | Wherever found | |
| Eastern Massasauga (=rattlesnake) | Sistrurus catenatus | Threatened | Wherever found | 09-30-2016 |
| Eastern Meadowlark | Sturnella magna | Species of Concern | Wherever found | |
| Eastern Mosquitofish | Gambusia holbrooki | Not Listed | | |
| Eastern narrowmouth toad | Gastrophryne carolinensis | Not Listed | | |
| Eastern native-cat | Dasyurus viverrinus | Endangered | Wherever found | 06-04-1973 |
| Eastern Oyster | Crassostrea virginica | Not Listed | | |
| Eastern painted bunting | Passerina ciris ciris | Species of Concern | Wherever found | |
| Eastern Pearlshell | Margaritifera margaritifera | Not Listed | | |
| Eastern pipistrelle | Pipistrellus subflavus | Status Undefined | Wherever found | |
| Eastern Pondmussel | Sagittunio nasutus | Not Listed | | |
| Eastern prairie fringed orchid | Platanthera leucophaea | Threatened | Wherever found | 09-28-1989 |
| Eastern puma (=cougar) | Puma (=Felis) concolor couguar | Extinction | Wherever found | 06-04-1973 |
| Eastern regal fritillary | Argynnis idalia idalia | Proposed Endangered | Wherever found | |
| Eastern Ribbon snake | Thamnophis sauritus | Status Undefined | Wherever found | |
| eastern rockhopper penguin | Eudyptes chrysocome filholi | Resolved Taxon | Wherever found | |
| Eastern sand darter | Ammocrypta pellucida | Species of Concern | Wherever found | |
| Eastern short-horned lizard | Phrynosoma douglassii brevirostra | Species of Concern | Wherever found | |
| Eastern Spiny Softshell Turtle | Apalone spinifera spinifera | Not Listed | | |
| Eastern Whip-poor-will | Antrostomus vociferus | Species of Concern | | |
| Eastern Whip-poor-will | Caprimulgus vociferus | Resolved Taxon | Wherever found | |
| Eastern Wood Pewee | Contopus virens | Species of Concern | Wherever found | |
| Eastwood's buckwheat | Eriogonum eastwoodianum | Resolved Taxon | Wherever found | |
| Eastwood's goldenweed | Ericameria fasciculata | Species of Concern | Wherever found | |
| Eastwood's milkweed | Asclepias eastwoodiana | Species of Concern | Wherever found | |
| Easy yellow-faced bee | Hylaeus facilis | Endangered | Wherever found | 10-31-2016 |
| Eaton's quillwort | Isoetes eatonii | Resolved Taxon | Wherever found | |
| Ebonyshell | Fusconaia ebena | Not Listed | | |
| Edge Falls anemone | Anemone edwardsiana petraea | Species of Concern | Wherever found | |
| Edgewood blind harvestman | Calcina minor | Species of Concern | Wherever found | |
| Edgewood Park micro-blind harvestman | Microcina edgewoodensis | Resolved Taxon | Wherever found | |
| Edison's ascyrum | Hypericum edisonianum | Resolved Taxon | | |
| Edisto crayfish | Procambarus echinatus | Resolved Taxon | Wherever found | |
| Edmund's snaketail | Ophiogomphus edmundo | Under Review | Wherever found | |
| Edwards Aquifer diving beetle | Haideoporus texanus | Under Review | Wherever found | |
| Edwards' brasil | Condalia hookeri edwardsiana | Species of Concern | Wherever found | |
| Edward's pheasant | Lophura edwardsi | Endangered | Wherever found | 06-02-1970 |
| Edwards' Plateau cornsalad | Valerianella texana | Species of Concern | Wherever found | |
| Eggert's sunflower | Helianthus eggertii | Recovery | Wherever found | 05-22-1997 |
| Egg Lake monkey-flower | Mimulus pygmaeus | Species of Concern | Wherever found | |
| Egg-mimic darter | Etheostoma pseudovulatum | Not Listed | Wherever found | |
| Egyptian Tortoise | Testudo kleinmanni | Threatened | Wherever found | 05-01-2023 |
| Eiao Marquesas reed-Warbler | Acrocephalus percernis aquilonis | Endangered | Wherever found | 09-12-2011 |
| Eke silversword | Argyroxiphium caliginis | Species of Concern | Wherever found | |
| El Dorado bedstraw | Galium californicum ssp. sierrae | Endangered | Wherever found | 10-18-1996 |
| El Dorado mule-ears | Wyethia reticulata | Species of Concern | Wherever found | |
| Eld's brow-antlered Deer | Cervus eldi | Endangered | Wherever found | 06-02-1970 |
| Elegant elimia | Elimia teres | Under Review | Wherever found | |
| Elegant Tern | Thalasseus elegans | Species of Concern | Wherever found | |
| Elegant Trogon | Trogon elegans | Species of Concern | Wherever found | |
| Elephant-Ear | Elliptio crassidens | Not Listed | | |
| Elevated Spring amphipod | Stygobromus elatus | Resolved Taxon | Wherever found | |
| Eleven Point River crayfish | Faxonius wagneri | Resolved Taxon | | |
| Elfin tree fern | Cyathea dryopteroides | Endangered | Wherever found | 06-16-1987 |
| Elfin-woods warbler | Setophaga angelae | Threatened | Wherever found | 07-22-2016 |
| Elf owl | Micrathene whitneyi | Species of Concern | Wherever found | |
| Elk | Cervus elaphus | Not Listed | | |
| Elkhorn coral | Acropora palmata | Threatened | Wherever found | 06-08-2006 |
| Elk River crayfish | Cambarus elkensis | Resolved Taxon | Wherever found | |
| Ellett Valley millipede | Pseudotremia cavernarum | Not Listed | | |
| Elliot's pheasant | Syrmaticus ellioti | Endangered | Wherever found | 06-14-1976 |
| ElliottÂ’s croton | Croton elliottii | Resolved Taxon | Wherever found | |
| Ellipse Mussel | Venustaconcha ellipsiformis | Not Listed | | |
| Elliptical Star Coral | Dichocoenia stokesi | Status Undefined | Wherever found | |
| Elongate-gland Springsnail | Pyrgulopsis isolata | Under Review | Wherever found | |
| Elongate mud meadows Springsnail | Pyrgulopsis notidicola | Resolved Taxon | Wherever found | |
| El Segundo blue butterfly | Euphilotes battoides allyni | Endangered | Wherever found | 06-08-1976 |
| El Segundo flower-loving fly | Rhaphiomidas terminatus terminatus | Resolved Taxon | Wherever found | |
| Elusive clubtail | Stylurus notatus | Species of Concern | Wherever found | |
| Elusive hydroporus diving beetle | Hydroporus elusivus | Species of Concern | Wherever found | |
| Emerald Shiner | Notropis atherinoides | Not Listed | | |
| Emerald Sleeper | Erotelis smaragdus | Not Listed | | |
| Emigrant pyrg | Pyrgulopsis gracilis | Resolved Taxon | Wherever found | |
| Emory acacia | Senegalia berlandieri | Resolved Taxon | Wherever found | |
| emperor penguin | Aptenodytes forsteri | Threatened | Wherever found | 11-25-2022 |
| Empire Cave pseudoscorpion | Microcreagris imperialis | Species of Concern | Wherever found | |
| Empire Mountain Talussnail | Sonorella imperialis | Resolved Taxon | Wherever found | |
| `Ena`ena | Pseudognaphalium sandwicensium var. molokaiense | Endangered | Wherever found | 10-31-2016 |
| Encinitas baccharis | Baccharis vanessae | Threatened | Wherever found | 10-07-1996 |
| Endless Caverns cave beetle | Pseudanophthalmus avernus | Not Listed | Wherever found | |
| Engelhardt's cave beetle | Pseudanophthalmus engelhardti | Species of Concern | Wherever found | |
| Engelmann oak | quercus engelmannii | Species of Concern | Wherever found | |
| Engelmann's goldenrod | Oonopsis engelmannii | Species of Concern | Wherever found | |
| Englewood mole | Scalopus aquaticus bassi | Species of Concern | Wherever found | |
| English Sole | Parophrys vetulus | Not Listed | | |
| Engraved covert | Fumonelix orestes | Resolved Taxon | Wherever found | |
| Engraved elimia | Elimia perstriata | Under Review | Wherever found | |
| Enterprise clarkia | Clarkia mosquinii xerophila | Species of Concern | Wherever found | |
| Enterprise siltsnail | Cincinnatia monroensis | Status Undefined | Wherever found | |
| Entrada skeletonplant | Lygodesmia entrada | Resolved Taxon | Wherever found | |
| Ephedra wild-buckwheat | Eriogonum ephedroides brevicaule | Resolved Taxon | Wherever found | |
| Ephemeral cave amphipod | Stygobromus ephemerus | Resolved Taxon | Wherever found | |
| erect-crested penguin | Eudyptes sclateri | Threatened | Wherever found | 09-02-2010 |
| Ernie''s mountain treasure | Rinodina brodoana | Species of Concern | | |
| Ertter's milk-vetch | Astragalus ertterae | Species of Concern | Wherever found | |
| Ertter's ragwort | Senecio ertterae | Resolved Taxon | Wherever found | |
| Erubia | Solanum drymophilum | Endangered | Wherever found | 08-26-1988 |
| Erythrodeme yellow-faced bee | Hylaeus erythrodemas | Resolved Taxon | Wherever found | |
| Escabrosa Talussnail | Sonorella bartschi | Resolved Taxon | Wherever found | |
| Escambia Map turtle | Graptemys ernsti | Similarity of Appearance (Threatened) | Wherever found | |
| Escarpment milk-vetch | Astragalus striatiflorus | Resolved Taxon | Wherever found | |
| Eskimo curlew | Numenius borealis | Endangered | Wherever found | 03-11-1967 |
| Esmeraldas woodstar | Chaetocercus berlepschi | Endangered | Wherever found | 11-29-2013 |
| Esperanza swallowtail butterfly | Papilio esperanza | Resolved Taxon | Wherever found | |
| Etonia rosemary | Conradina etonia | Endangered | | 07-12-1993 |
| Etowah crayfish | Cambarus fasciatus | Status Undefined | Wherever found | |
| Etowah darter | Etheostoma etowahae | Endangered | Wherever found | 12-20-1994 |
| Eulachon | Thaleichthys pacificus | Not Listed | Wherever found | |
| Eulachon | Thaleichthys pacificus | Threatened | Southern DPS - See 50 CFR 223.102 | 04-13-2011 |
| Euler's flycatcher | Empidonax euleri johnstonei | Endangered | Wherever found | 06-02-1970 |
| Eulophia | Pteroglossaspis ecristata | Species of Concern | Wherever found | |
| Eurasian peregrine falcon | Falco peregrinus peregrinus | Endangered | Wherever found | 06-14-1976 |
| Eurasian Siskin | Spinus spinus | Species of Concern | | |
| Eureka Dune grass | Swallenia alexandrae | Threatened | | 05-27-1978 |
| Eureka mountainsnail | Oreohelix eurekensis eurekensis | Species of Concern | Wherever found | |
| Eureka Mountainsnail | Oreohelix eurekensis | Resolved Taxon | Wherever found | |
| Eureka Valley evening-primrose | Oenothera avita ssp. eurekensis | Recovery | | 05-27-1978 |
| European sturgeon | Acipenser sturio | Endangered | Wherever found | 09-04-2014 |
| Evalyn's jewelflower | Streptanthus farnsworthianus | Resolved Taxon | Wherever found | |
| Evelyn''s buttons | Buellia sharpiana | Species of Concern | | |
| Evening fieldslug | Deroceras hesperium | Resolved Taxon | Wherever found | |
| Evening Grosbeak | Coccothraustes vespertinus | Species of Concern | Wherever found | |
| Evening Talussnail | Sonorella vespertina | Resolved Taxon | Wherever found | |
| Everglades brownwing firefly | Photuris brunnipennis floridana | Species of Concern | Wherever found | |
| Everglades bully | Sideroxylon reclinatum ssp. austrofloridense | Threatened | | 10-06-2017 |
| Everglades mink | Mustela vison evergladensis | Resolved Taxon | Wherever found | |
| Everglade snail kite | Rostrhamus sociabilis plumbeus | Endangered | Wherever found | 03-11-1967 |
| Evergreen everlasting | Antennaria suffrutescens | Resolved Taxon | Wherever found | |
| Evermann's rock ptarmigan | Lagopus muta evermanni | Species of Concern | Wherever found | |
| Ewan's paintbrush | Castilleja martinii ewanii | Resolved Taxon | Wherever found | |
| Excised slitshell | Gyrotoma excisa | Resolved Taxon | Wherever found | |
| Exiguous anomalan scarab | Anomala exigua | Species of Concern | Wherever found | |
| Extra-striped snaketail | Ophiogomphus anomalus | Species of Concern | Wherever found | |
| Exuma Island iguana | Cyclura cychlura figginsi | Threatened | Wherever found | 06-22-1983 |
| Eyrean grasswren (flycatcher) | Amytornis goyderi | Endangered | Wherever found | 06-02-1970 |
| Ezell's Cave amphipod | Stygobromus flagellatus | Species of Concern | Wherever found | |
| Fabulous green sphinx Moth | Tinostoma smaragditis | Resolved Taxon | Wherever found | |
| Fadang | Cycas micronesica | Threatened | | 11-02-2015 |
| Fairbanks springsnail | Pyrgulopsis fairbanksensis | Resolved Taxon | Wherever found | |
| Fairchild's lily | Lilium fairchildii | Resolved Taxon | Wherever found | |
| Falfurrias anglepod | Matelea radiata | Species of Concern | Wherever found | |
| Fallax megalagrion damselfly | Megalagrion amaurodytum fallax | Resolved Taxon | Wherever found | |
| Fall-flowering ixia | Nemastylis floridana | Species of Concern | Wherever found | |
| False ameletus mayfly | Ameletus falsus | Species of Concern | Wherever found | |
| False dragon-head | Physostegia leptophylla | Resolved Taxon | Wherever found | |
| False hellebore | Veratrum woodii | Resolved Taxon | Wherever found | |
| False indian-mallow | Anoda abutiloides | Resolved Taxon | Wherever found | |
| false killer whale | Pseudorca crassidens | Endangered | Main Hawaiian Islands Insular DPS See 50 CFR 224.101 | 12-28-2012 |
| False map turtle | Graptemys pseudogeographica | Species of Concern | Wherever found | |
| false spike | Fusconaia mitchelli | Endangered | Wherever found | 07-05-2024 |
| False water rat | Xeromys myoides | Endangered | Wherever found | 12-02-1970 |
| Fanshell | Cyprogenia stegaria | Endangered | Wherever found | 06-21-1990 |
| Fanshell | Cyprogenia stegaria | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Fantail Darter | Etheostoma flabellare | Not Listed | | |
| Fan-tailed Warbler | Basileuterus lachrymosus | Species of Concern | | |
| Fassett's locoweed | Oxytropis campestris var. chartacea | Threatened | Wherever found | 09-28-1988 |
| Fathead Minnow | Pimephales promelas | Not Listed | | |
| Fatmucket | Lampsilis siliquoidea | Not Listed | | |
| Fat pocketbook | Potamilus capax | Endangered | Wherever found | 06-14-1976 |
| Fat Sleeper | Dormitator maculatus | Not Listed | | |
| Fat threeridge (mussel) | Amblema neislerii | Endangered | Wherever found | 03-16-1998 |
| Fat-whorled (=Bonneville) pondsnail | Stagnicola bonnevillensis | Resolved Taxon | Wherever found | |
| Faurie's panic grass | Panicum fauriei fauriei | Resolved Taxon | Wherever found | |
| Fawnsfoot Mussel | Truncilla donaciformis | Not Listed | | |
| Faxon's clam shrimp | Eulimnadia agassizii | Species of Concern | Wherever found | |
| Fea's muntjac | Muntiacus feae | Endangered | Wherever found | 07-27-1979 |
| Fea's Petrel | Pterodroma feae | Species of Concern | | |
| Feather River monardella | Monardella stebbinsii | Resolved Taxon | Wherever found | |
| Feather River stonecrop | Sedum albomarginatum | Resolved Taxon | Wherever found | |
| Fell fields claytonia | Claytonia megarhiza bellidiflora | Resolved Taxon | Wherever found | |
| Felt leaf rock-mint | Monardella hypoleuca lanata | Resolved Taxon | Wherever found | |
| Felt-leaf violet | Viola tomentosa | Resolved Taxon | Wherever found | |
| Fender's blue butterfly | Icaricia icarioides fenderi | Threatened | Wherever found | 01-25-2000 |
| Fender's rhyacophilan caddisfly | Rhyacophila fenderi | Resolved Taxon | Wherever found | |
| Fender's soliperlan stonefly | Soliperla fenderi | Species of Concern | Wherever found | |
| Fenney Spring hydrobe | Aphaostracon xynoelictum | Species of Concern | Wherever found | |
| Fern-leaved ironwood | Lyonothamnus floribundus asplenifolius | Species of Concern | Wherever found | |
| Fern yellow-faced bee | Hylaeus filicum | Species of Concern | Wherever found | |
| Ferris' milk-vetch | Astragalus tener var. ferrisae | Species of Concern | Wherever found | |
| Ferris''s copper | Lycaena ferrisi | Under Review | Wherever found | |
| Ferruginous Hawk | Buteo regalis | Resolved Taxon | Wherever found | |
| Few-flowered jewelflower | Streptanthus sparsiflorus | Species of Concern | Wherever found | |
| Few-flowered navarretia | Navarretia leucocephala ssp. pauciflora (=N. pauciflora) | Endangered | Wherever found | 06-18-1997 |
| fewflower milkweed | Asclepias lanceolata | Not Listed | | |
| Fibrillose lip fern | Cheilanthes fibrillosa | Resolved Taxon | Wherever found | |
| Fickeisen plains cactus | Pediocactus peeblesianus ssp. fickeiseniae | Endangered | Wherever found | 10-31-2013 |
| Field goldeneye | Viguiera phenax | Resolved Taxon | Wherever found | |
| Field, long-hairy chickweed | Cerastium arvense villosissimum | Species of Concern | Wherever found | |
| Field's mouse | Pseudomys fieldi | Endangered | Wherever found | 12-02-1970 |
| Field Sparrow | Spizella pusilla | Species of Concern | Wherever found | |
| Fig seed diving beetle | Desmopachria cenchramis | Species of Concern | Wherever found | |
| Fiji banded iguana | Brachylophus fasciatus | Endangered | Wherever found | 03-20-1980 |
| Fiji crested iguana | Brachylophus vitiensis | Endangered | Wherever found | 03-20-1980 |
| Fiji petrel | Pseudobulweria macgillivrayi | Endangered | Wherever found | 09-14-2009 |
| Fiji Shrikebill | Clytorhynchus vitiensis | Species of Concern | Wherever found | |
| Finback whale | Balaenoptera physalus | Endangered | Wherever found | 06-02-1970 |
| Finelined pocketbook | Hamiota altilis | Threatened | Wherever found | 03-17-1993 |
| Finerayed pigtoe | Fusconaia cuneolus | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Finerayed pigtoe | Fusconaia cuneolus | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Finerayed pigtoe | Fusconaia cuneolus | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Finescale Dace | Chrosomus neogaeus | Not Listed | | |
| Finitiman yellow-faced bee | Hylaeus finitima | Resolved Taxon | Wherever found | |
| fiordland crested penguin | Eudyptes pachyrhynchus | Threatened | Wherever found | 09-02-2010 |
| Fischer's lelpidostoman caddisfly | Lepidostoma fischeri | Resolved Taxon | Wherever found | |
| Fish Creek fleabane | Erigeron piscaticus | Under Review | Wherever found | |
| Fish Creek rock-daisy | Perityle saxicola | Resolved Taxon | Wherever found | |
| Fish Creek Springs tui chub | Siphateles bicolor euchila | Species of Concern | Wherever found | |
| Fisher | Pekania pennanti | Endangered | Southern Sierra Nevada Distinct Population Segment | 06-15-2020 |
| Fisher | Pekania pennanti | Resolved Taxon | Northern California/Southern Oregon Distinct Population Segment | 05-15-2020 |
| Fisher | Pekania pennanti | Resolved Taxon | Northern Rocky Mountains DPS | |
| Fisher | Pekania pennanti | Resolved Taxon | West Coast Distinct Population Segment | 05-15-2020 |
| Fisher | Pekania pennanti | Species of Concern | Great Lakes | |
| Fish Lake naiad | Najas flexilis | Species of Concern | Wherever found | |
| Fish Lake physa | Physella microstriata | Species of Concern | Wherever found | |
| Fish Lake Valley tui chub | Siphateles obesus ssp. | Under Review | Fish Lake | |
| Fish Slough milk-vetch | Astragalus lentiginosus var. piscinensis | Threatened | Wherever found | 10-06-1998 |
| Fish Slough springsnail | Pyrgulopsis perturbata | Species of Concern | Wherever found | |
| Fish's milkwort | Polygala cornuta var. fishiae | Species of Concern | Wherever found | |
| Fish Spring pocket gopher | Thomomys umbrinus abstrusus | Species of Concern | Wherever found | |
| Fish Springs marshsnail | Stagnicola pilsbryi | Resolved Taxon | Wherever found | |
| Fitch's hedgehog cactus | Echinocereus reichenbachii fitchii | Resolved Taxon | Wherever found | |
| Five-striped Sparrow | Aimophila quinquestriata | Species of Concern | Wherever found | |
| Flag pyrg | Pyrgulopsis breviloba | Resolved Taxon | Wherever found | |
| Flagstaff pennyroyal | Hedeoma diffusum | Resolved Taxon | Wherever found | |
| Flaky square britches | Hypotrachyna virginica | Species of Concern | | |
| Flame chub | Hemitremia flammea | Species of Concern | Wherever found | |
| Flammulated Owl | Psiloscops flammeolus | Status Undefined | Wherever found | |
| Flannelmouth sucker | Catostomus latipinnis | Species of Concern | Wherever found | |
| Flat dune sedge | Cyperus onerosus | Species of Concern | Wherever found | |
| Flat Floater Mussel | Utterbackiana suborbiculata | Not Listed | | |
| Flathead Catfish | Pylodictis olivaris | Not Listed | | |
| Flathead chub | Platygobio gracilis | Species of Concern | Wherever found | |
| Flat-headed cat | Prionailurus (=Felis) planiceps | Endangered | Wherever found | 06-14-1976 |
| Flathead Pondsnail | Stagnicola elrodi | Resolved Taxon | Wherever found | |
| Flat pebblesnail | Lepyrium showalteri | Endangered | Wherever found | 10-28-1998 |
| Flat pigtoe | Pleurobema marshalli | Extinction | Wherever found | 04-07-1987 |
| Flat-seeded spurge | Chamaesyce platysperma | Species of Concern | Wherever found | |
| Flat-spired three-toothed Snail | Triodopsis platysayoides | Threatened | Wherever found | 08-02-1978 |
| Flat-tailed horned lizard | Phrynosoma mcallii | Resolved Taxon | Wherever found | |
| Flat-tailed tortoise | Pyxis planicauda | Under Review | Wherever found | |
| Flattened musk turtle | Sternotherus depressus | Threatened | Black Warrior R. system upstream from Bankhead Dam | 06-11-1987 |
| Flat-topped Steptoe pyrg | Pyrgulopsis planulata | Under Review | Wherever found | |
| Flaxen elimia | Elimia boykiniana | Species of Concern | Wherever found | |
| Flax-like monardella | Monardella linoides oblonga | Species of Concern | Wherever found | |
| Fleshy-fruit gladecress | Leavenworthia crassa | Endangered | Wherever found | 08-01-2014 |
| Fleshy owl's-clover | Castilleja campestris ssp. succulenta | Threatened | Wherever found | 03-26-1997 |
| Fletcher dark kangaroo mouse | Microdipodops megacephalus nasutus | Species of Concern | Wherever found | |
| Flett's violet | Viola flettii | Resolved Taxon | Wherever found | |
| Flint River pyrg | Pyrgulopsis sp. | Species of Concern | Flint R. | |
| Flint's net-spinning caddisfly | Cheumatopsyche flinti | Resolved Taxon | Wherever found | |
| Floreana tree-Finch | Camarhynchus pauper | Endangered | Wherever found | 08-26-2010 |
| Flores hawk-eagle | Spizaetus floris | Under Review | Wherever found | |
| Florida arc-mussel | Alasmidonta wrightiana | Species of Concern | Wherever found | |
| Florida asaphomyian tabanid fly | Asaphomyia floridensis | Species of Concern | Wherever found | |
| Florida atala butterfly | Eumaeus atala florida | Species of Concern | Wherever found | |
| Florida black bear | Ursus americanus floridanus | Resolved Taxon | Wherever found | |
| Florida bog frog | Rana okaloosae | Resolved Taxon | Wherever found | |
| Florida Bog Frog | Lithobates okaloosae | Not Listed | | |
| Florida bonamia | Bonamia grandiflora | Threatened | | 11-02-1987 |
| Florida bonneted bat | Eumops floridanus | Endangered | Wherever found | 11-01-2013 |
| Florida brickell-bush | Brickellia mosieri | Endangered | | 10-06-2014 |
| Florida bristle fern | Trichomanes punctatum ssp. floridanum | Endangered | | 11-05-2015 |
| Florida brown checkered summer sedge | Polycentropus floridensis | Resolved Taxon | Wherever found | |
| Florida Burrowing Owl | Athene cunicularia floridana | Species of Concern | | |
| Florida cave amphipod | Crangonyx grandimanus | Under Review | Wherever found | |
| Florida Cave crayfish | Procambarus lucifugus | Under Review | Wherever found | |
| Florida Cave crayfish | Procambarus lucifugus ssp. lucifugus | Under Review | Wherever found | |
| Florida ceraclean longhorn caddisfly | Ceraclea floridana | Species of Concern | Wherever found | |
| Florida coontie | Zamia integrifolia pigmaea | Resolved Taxon | Wherever found | |
| Florida crawfish frog | Rana areolata aesopus | Species of Concern | Wherever found | |
| Florida fairy shrimp | Dexteria floridana | Resolved Taxon | Wherever found | |
| Florida Gar | Lepisosteus platyrhincus | Not Listed | | |
| Florida golden aster | Chrysopsis floridana | Recovery | | 05-16-1986 |
| Florida grasshopper sparrow | Ammodramus savannarum floridanus | Endangered | Wherever found | 07-31-1986 |
| Florida hartwrightia | Hartwrightia floridana | Under Review | Wherever found | |
| Florida hornwort | Ceratophyllum floridanum | Resolved Taxon | Wherever found | |
| Florida indigo | Indigofera mucronata var. keyensis | Resolved Taxon | Wherever found | |
| Florida intertidal firefly | Micronaspis floridana | Under Review | Wherever found | |
| Florida Keys mole skink | Plestiodon egregius egregius | Proposed Threatened | Wherever found | |
| Florida lance | Elliptio waltoni | Species of Concern | Wherever found | |
| Florida leafwing Butterfly | Anaea troglodyta floridalis | Endangered | Wherever found | 09-11-2014 |
| Florida long-tailed weasel | Mustela frenata peninsulae | Species of Concern | Wherever found | |
| Florida loosestrife | Lythrum flagellare | Resolved Taxon | | |
| Florida Manatee | Trichechus manatus latirostris | Proposed Threatened | Wherever Found | |
| Florida mastiff-bat | Eumops glaucinus floridanus | Species of Concern | Wherever found | |
| Florida mink | Mustela vison lutensis | Resolved Taxon | Wherever found | |
| Florida mountainsnail | Oreohelix florida | Species of Concern | Wherever found | |
| Florida Mountain Woodlandsnail | Ashmunella walkeri | Resolved Taxon | Wherever found | |
| Florida mouse | Peromyscus floridanus | Species of Concern | Wherever found | |
| Florida oxyethiran micro caddisfly | Oxyethira florida | Species of Concern | Wherever found | |
| Florida panther | Puma (=Felis) concolor coryi | Endangered | Wherever found | 03-11-1967 |
| Florida perforate cladonia | Cladonia perforata | Endangered | | 04-27-1993 |
| Florida pineland crabgrass | Digitaria pauciflora | Threatened | | 10-06-2017 |
| Florida pinesnake | Pituophis melanoleucus mugitus | Resolved Taxon | Wherever found | |
| Florida Pompano | Trachinotus carolinus | Not Listed | | |
| Florida pondweed | Potamogeton floridanus | Under Review | Wherever found | |
| Florida prairie-clover | Dalea carthagenensis floridana | Endangered | | 10-06-2017 |
| Florida Red-bellied turtle | Pseudemys nelsoni | Under Review | Wherever found | |
| Florida salt marsh vole | Microtus pennsylvanicus dukecampbelli | Endangered | Wherever found | 01-14-1991 |
| Florida sandhill crane | Antigone canadensis ssp. pratensis | Resolved Taxon | Wherever found | |
| Florida scrub-jay | Aphelocoma coerulescens | Threatened | Wherever found | 06-03-1987 |
| Florida scrub lizard | Sceloporus woodi | Under Review | Wherever found | |
| Florida semaphore Cactus | Consolea corallicola | Endangered | | 11-25-2013 |
| Florida skullcap | Scutellaria floridana | Threatened | | 05-08-1992 |
| Florida Stone Crab | Menippe mercenaria | Not Listed | | |
| Florida torreya | Torreya taxifolia | Endangered | | 01-23-1984 |
| Florida tree snail | Liguus fasciatus | Resolved Taxon | Wherever found | |
| Florida water-parsnip | Sium suave | Species of Concern | Wherever found | |
| Florida willow | Salix floridana | Under Review | Wherever found | |
| Florida yew | Taxus floridana | Species of Concern | Wherever found | |
| Florida ziziphus | Ziziphus celata | Endangered | | 07-27-1989 |
| Fluminense swallowtail butterfly | Parides ascanius | Endangered | Wherever found | 01-09-2025 |
| Fluted Elephantear | Elliptio mcmichaeli | Status Undefined | Wherever found | |
| Fluted kidneyshell | Ptychobranchus subtentus | Endangered | Wherever found | 10-28-2013 |
| Fluted pebblesnail | Somatogyrus hendersoni | Species of Concern | Wherever found | |
| Fluted-Shell | Lasmigona costata | Not Listed | | |
| Flying earwig Hawaiian damselfly | Megalagrion nesiotes | Endangered | Wherever found | 07-26-2010 |
| Flyn's hick cave beetle | Pseudanophthalmus simplex | Species of Concern | Wherever found | |
| Flypoison borer moth | Papaipema sp. | Species of Concern | Wherever found | |
| Flyr's brickell-bush | Brickellia cordifolia | Species of Concern | Wherever found | |
| Folkerts' hydroporus diving beetle | Hydroporus folkertsi | Species of Concern | Wherever found | |
| Foothill mariposa lily | Calochortus weedii intermedius | Species of Concern | Wherever found | |
| Foothill yellow-legged frog | Rana boylii | Endangered | California, Coast Range from Monterey County south to Los Angeles County | 09-28-2023 |
| Foothill yellow-legged frog | Rana boylii | Endangered | California, Sierra Nevada Mountains south of American River sub-basin south to Transverse Range, Kern County | 09-28-2023 |
| Foothill yellow-legged frog | Rana boylii | Threatened | California, Central Coast Range south of San Francisco Bay to San Benito and Fresno Counties | 09-28-2023 |
| Foothill yellow-legged frog | Rana boylii | Threatened | California, North Feather River watershed largely in Plumas and Butte Counties | 09-28-2023 |
| Footsteps of spring | Sanicula arctopoides | Species of Concern | Wherever found | |
| Forbes bidens | Bidens forbesii | Resolved Taxon | Wherever found | |
| Forbes' Kauai long-horned beetle | Plagithmysus forbesianus | Species of Concern | Wherever found | |
| Forbes' Maui long-horned beetle | Plagithmysus forbesii | Species of Concern | Wherever found | |
| Forbes' parakeet | Cyanoramphus auriceps forbesi | Endangered | Wherever found | 06-02-1970 |
| Forbes saxifrage | Micranthes pensylvanica | Resolved Taxon | Wherever found | |
| Ford's aphodius scarab | Aphodius fordi | Species of Concern | Wherever found | |
| Ford's rhyncogonus weevil | Rhyncogonus segnis fordi | Species of Concern | Wherever found | |
| Ford's sand dune moth | Psammobotys fordi | Species of Concern | Wherever found | |
| Forest Camp sandwort | Arenaria macradenia kuschei | Species of Concern | Wherever found | |
| Forked buckwheat | Eriogonum bifurcatum | Species of Concern | Wherever found | |
| Forked fiddleneck | Amsinckia vernicosa furcata | Species of Concern | Wherever found | |
| Forkshell | Epioblasma lewisii | Resolved Taxon | Wherever found | |
| Formosan rock macaque | Macaca cyclopis | Threatened | Wherever found | 10-19-1976 |
| Formosan sika deer | Cervus nippon taiouanus | Endangered | Wherever found | 07-27-1979 |
| Formosan yellow-throated marten | Martes flavigula chrysospila | Endangered | Wherever found | 06-02-1970 |
| Forster's Tern | Sterna forsteri | Species of Concern | | |
| Fort Dick limnephilus caddisfly | Limnephilus atercus | Species of Concern | Wherever found | |
| Fort Mountain Sedge | Carex communis var. amplisquama | Species of Concern | Wherever found | |
| Fort Ross trigonoscuta weevil | Trigonoscuta rossi | Resolved Taxon | Wherever found | |
| Fosberg's love grass | Eragrostis fosbergii | Endangered | Wherever found | 10-10-1996 |
| Foskett speckled dace | Rhinichthys osculus ssp. | Recovery | Wherever found | 03-28-1985 |
| Fossil springsnail | Pyrgulopsis simplex | Resolved Taxon | Wherever found | |
| Foster's Rockdaisy | Perityle fosteri | Resolved Taxon | Wherever found | |
| Fountain darter | Etheostoma fonticola | Endangered | Wherever found | 10-13-1970 |
| Fountain thistle | Cirsium fontinale var. fontinale | Endangered | Wherever found | 02-03-1995 |
| Fourche Mountain salamander | Plethodon fourchensis | Resolved Taxon | Wherever found | |
| Four-petal pawpaw | Asimina tetramera | Endangered | | 09-26-1986 |
| Four-Toed Salamander | Hemidactylium scutatum | Not Listed | | |
| Fowler's cave beetle | Pseudanophthalmus fowlerae | Resolved Taxon | Wherever found | |
| Fox Sparrow | Passerella iliaca | Species of Concern | Wherever found | |
| Foxtail cactus | escobaria alversonii | Species of Concern | Wherever found | |
| Fragile Papershell | Potamilus fragilis | Not Listed | | |
| Fragile supercoil | Glyphyalinia clingmani | Species of Concern | Wherever found | |
| Fragile tree snail | Samoana fragilis | Endangered | Wherever found | 11-02-2015 |
| Fragrant flatsedge | Cyperus odoratus | Resolved Taxon | Wherever found | |
| Fragrant fritillary | Fritillaria liliacea | Species of Concern | Wherever found | |
| Fragrant prickly-apple | Cereus eriophorus var. fragrans | Endangered | | 11-01-1985 |
| Franciscan manzanita | Arctostaphylos franciscana | Endangered | Wherever found | 10-05-2012 |
| Francois' langur | Trachypithecus (=Presbytis) francoisi | Endangered | Wherever found | 10-19-1976 |
| Franklin Mountain talussnail | Sonorella metcalfi | Species of Concern | Wherever found | |
| Franklin Mountain wood snail | Ashmunella pasonis | Species of Concern | Wherever found | |
| Franklin's bumble bee | Bombus franklini | Endangered | Wherever found | 09-23-2021 |
| Franklin's ground squirrel | Spermophilus franklinii | Under Review | Wherever found | |
| Franklin's Gull | Leucophaeus pipixcan | Species of Concern | | |
| Franklin tree | Franklinia alatamaha | Species of Concern | Wherever found | |
| Frank Smith's violet | Viola franksmithii | Resolved Taxon | Wherever found | |
| Franz's amphipod | Stygobromus franzi | Resolved Taxon | Wherever found | |
| Franz's isopod | Caecidotea franzi | Species of Concern | Wherever found | |
| Fraser fir | Abies fraseri | Species of Concern | Wherever found | |
| Fraser fir geometrid moth | Semiothisa fraserata | Species of Concern | Wherever found | |
| Fraser's yellow loosestrife | Lysimachia fraseri | Species of Concern | Wherever found | |
| Frecklebelly madtom | Noturus munitus | Resolved Taxon | Wherever found | |
| Frecklebelly madtom | Noturus munitus | Threatened | Upper Coosa River Distinct Population Segment | 04-03-2023 |
| Freckled darter | Percina lenticula | Resolved Taxon | Wherever found | |
| Fredonia wild-buckwheat | Eriogonum mortonianum | Under Review | Wherever found | |
| Freed's jewelflower | Streptanthus brachiatus hoffmanii | Species of Concern | Wherever found | |
| Freemouth Hydrobe snail | Aphaostracon chalarogyrus | Status Undefined | Wherever found | |
| Freira | Pterodroma madeira | Endangered | Wherever found | 01-12-1995 |
| Fremont County rockcress | Boechera pusilla | Resolved Taxon | Wherever found | |
| Fremont's bladder-pod | Lesquerella fremontii | Resolved Taxon | Wherever found | |
| Fremont's rosinweed | Calycadenia fremontii | Species of Concern | Wherever found | |
| French Broad crayfish | Cambarus reburrus | Species of Concern | Wherever found | |
| French Broad heartleaf | Hexastylis rhombiformis | Species of Concern | Wherever found | |
| French Frigate Shoal seed bug | Nysius frigatensis | Species of Concern | Wherever found | |
| French's shootingstar | Dodecatheon frenchii | Resolved Taxon | Wherever found | |
| Freshwater Drum | Aplodinotus grunniens | Not Listed | | |
| Freshwater Pipefish | Pseudophallus mindii | Not Listed | | |
| Fresno County bird's-beak | Cordylanthus tenuis barbatus | Species of Concern | Wherever found | |
| Fresno Creek thelypody | Thelypodium tenue | Resolved Taxon | Wherever found | |
| Fresno kangaroo rat | Dipodomys nitratoides exilis | Endangered | Wherever found | 01-30-1985 |
| Friendly Ground-Dove | Gallicolumba stairi | Endangered | American Samoa DPS | 10-24-2016 |
| Frigid Ambersnail | Catinella gelida | Resolved Taxon | Wherever found | |
| Fringe-backed fire-eye | Pyriglena atra | Endangered | Wherever found | 01-27-2011 |
| Fringed campion | Silene polypetala | Endangered | Wherever found | 01-18-1991 |
| Fringed false-hellebore | Veratrum fimbriatum | Resolved Taxon | Wherever found | |
| Fringed loosestrife | Lysimachia hybrida | Resolved Taxon | Wherever found | |
| Fringed Mountainsnail | Radiocentrum ferrissi | Resolved Taxon | Wherever found | |
| Fringed myotis | Myotis thysanodes | Species of Concern | Wherever found | |
| Fringed Ornamental Tarantula | Poecilotheria ornata | Endangered | Wherever found | 08-30-2018 |
| Fringed-tailed myotis | Myotis thysanodes pahasapensis | Species of Concern | Wherever found | |
| Fringed (unnamed ssp.) lewisia | Lewisia cotyledon ssp. | Resolved Taxon | Wherever found | |
| Frisco buckwheat | Eriogonum soredium | Resolved Taxon | Wherever found | |
| Frisco clover | Trifolium friscanum | Resolved Taxon | Wherever found | |
| Frison's seratellan mayfly | Seratella frisoni | Species of Concern | Wherever found | |
| Front Range cinquefoil | Potentilla effusa rupincola | Species of Concern | Wherever found | |
| Frosted Elfin | Callophrys irus irus, C. i. hadros, C. i. arsace | Status Undefined | Wherever found | |
| Frosted Flatwoods salamander | Ambystoma cingulatum | Threatened | Wherever found | 04-01-1999 |
| Frost's spring serican scarab | Serica frosti | Species of Concern | Wherever found | |
| Fruit rock-cress | Arabis fructicosa | Resolved Taxon | Wherever found | |
| Ft. Tejon wooly-sunflower | Eriophyllum lanatum hallii | Species of Concern | Wherever found | |
| Fullaway's banana omoides moth | Omoides fullawayi | Species of Concern | Wherever found | |
| Fullaway's seed bug | Nysius fullawayi | Species of Concern | Wherever found | |
| Fulvous whistling duck | Dendrocygna bicolor | Species of Concern | Wherever found | |
| Funeral ephedra | Ephedra funerea | Resolved Taxon | Wherever found | |
| Furbish lousewort | Pedicularis furbishiae | Threatened | | 05-27-1978 |
| Furry yellow-faced bee | Hylaeus pubescens | Species of Concern | Wherever found | |
| Fusiform elimia | Elimia fusiformis | Resolved Taxon | Wherever found | |
| Fuzzy pigtoe | Pleurobema strodeanum | Threatened | Wherever found | 10-10-2012 |
| Gaimard's rat-kangaroo | Bettongia gaimardi | Endangered | Wherever found | 06-04-1973 |
| Gairdner's yampah | Perideridia gairdneri gairdneri | Species of Concern | Wherever found | |
| Galapagos hawk | Buteo galapagoensis | Endangered | Wherever found | 06-02-1970 |
| Galapagos penguin | Spheniscus mendiculus | Endangered | Wherever found | 06-02-1970 |
| Galapagos petrel | Pterodroma phaeopygia | Threatened | Wherever found | 01-05-2010 |
| Galapagos tortoise | Geochelone nigra (=elephantopus) | Endangered | Wherever found | 06-02-1970 |
| Galena Creek rock-cress | Arabis rigidissima demota | Species of Concern | Wherever found | |
| Gambel's watercress | Rorippa gambellii | Endangered | Wherever found | 08-03-1993 |
| Gammon's stenelmis riffle beetle | Stenelmis gammoni | Species of Concern | Wherever found | |
| Gander butterweed | Packera ganderi | Species of Concern | Wherever found | |
| Gander's cryptantha | Cryptantha ganderi | Resolved Taxon | Wherever found | |
| Gander's pitcher-sage | Lepechinia ganderi | Species of Concern | Wherever found | |
| Gandy Creek cave springtail | Pseudosinella certa | Species of Concern | Wherever found | |
| Garber's spurge | Chamaesyce garberi | Threatened | | 07-18-1985 |
| Garden Canyon talussnail | Sonorella dalli | Resolved Taxon | Wherever found | |
| Garden cave beetle | Pseudanophthalmus hortulanus | Species of Concern | Wherever found | |
| Garrett bladder-pod | Lesquerella garrettii | Species of Concern | Wherever found | |
| Garrett's beardtongue | Penstemon scariosus garrettii | Resolved Taxon | Wherever found | |
| Garrett's mint | Dicerandra christmanii | Endangered | | 11-01-1985 |
| Gaspe Peninsula arrow-grass | Triglochin gaspense | Species of Concern | Wherever found | |
| Gavial | Gavialis gangeticus | Endangered | Wherever found | 06-02-1970 |
| Gaviota Tarplant | Deinandra increscens ssp. villosa | Endangered | Wherever found | 03-20-2000 |
| Gelada baboon | Theropithecus gelada | Threatened | Wherever found | 10-19-1976 |
| Gentian pinkroot | Spigelia gentianoides | Endangered | | 11-26-1990 |
| Gentner's Fritillary | Fritillaria gentneri | Endangered | Wherever found | 12-10-1999 |
| Gentry's indigobush | Dalea tentaculoides | Resolved Taxon | Wherever found | |
| Geometric turtle | Psammobates geometricus | Endangered | Wherever found | 06-14-1976 |
| Georgetown Salamander | Eurycea naufragia | Threatened | Wherever found | 03-26-2014 |
| Georgia aster | Symphyotrichum georgianum | Resolved Taxon | Wherever found | |
| Georgia beloneurian stonefly | Beloneuria georgiana | Resolved Taxon | Wherever found | |
| Georgia blind salamander | Eurycea wallacei | Resolved Taxon | Wherever found | |
| Georgia bully | Sideroxylon thornei | Resolved Taxon | Wherever found | |
| Georgia lead-plant | Amorpha georgiana georgiana | Under Review | Wherever found | |
| Georgian cave beetle | Pseudanophthalmus georgiae | Species of Concern | Wherever found | |
| Georgia pigtoe | Pleurobema hanleyianum | Endangered | Wherever found | 12-02-2010 |
| Georgia plume | Elliottia racemosa | Resolved Taxon | Wherever found | |
| Georgia rockcress | Arabis georgiana | Threatened | Wherever found | 10-14-2014 |
| Germanus eopenthes click beetle | Eopenthes germanus | Species of Concern | Wherever found | |
| Ghizo white-eye | Zosterops luteirostris | Candidate | Wherever found | |
| Ghost orchid | Dendrophylax lindenii | Under Review | | |
| Giant armadillo | Priodontes maximus | Endangered | Wherever found | 06-14-1976 |
| Giant Floater | Pyganodon grandis | Not Listed | | |
| Giant garter snake | Thamnophis gigas | Threatened | Wherever found | 10-20-1993 |
| Giant ibis | Pseudibis gigantea | Endangered | Wherever found | 01-16-2008 |
| Giant kangaroo rat | Dipodomys ingens | Endangered | Wherever found | 01-05-1987 |
| Giant koke`e | Cyanea leptostegia | Species of Concern | Wherever found | |
| Giant Manta Ray | Manta birostris | Threatened | | |
| Giant otter | Pteronura brasiliensis | Endangered | South America | 06-02-1970 |
| Giant Palouse earthworm | Driloleirus americanus | Resolved Taxon | Wherever found | |
| Giant panda | Ailuropoda melanoleuca | Endangered | Wherever found | 01-23-1984 |
| Giant pangolin | Manis gigantea | Under Review | Wherever found | |
| Giant sable antelope | Hippotragus niger variani | Endangered | Wherever found | 06-02-1970 |
| Giant scops owl | Mimizuku (=Otus) gurneyi | Endangered | Wherever found | 06-14-1976 |
| Giant spanishneedle | Palafoxia arida gigantea | Species of Concern | Wherever found | |
| Giant Trevally, Ulua | Caranx ignobilis | Not Listed | | |
| Giant water-dropwort | Oxypolis greenmanii | Resolved Taxon | Wherever found | |
| Gibbens beardtongue | Penstemon gibbensii | Resolved Taxon | Wherever found | |
| Gibbons | Hylobates spp. (including Nomascus) | Endangered | Wherever found | 06-02-1970 |
| Gierisch mallow | Sphaeralcea gierischii | Endangered | Wherever found | 09-12-2013 |
| Giffard's ectemnius sphecid wasp | Ectemnius giffardi | Species of Concern | Wherever found | |
| Giffard's `ohe omoides moth | Omoides giffardi | Species of Concern | Wherever found | |
| Giffard's rhyncogonus weevil | Rhyncogonus giffardi | Species of Concern | Wherever found | |
| Gifford's nesotocus weevil | Nesotocus giffordi | Species of Concern | Wherever found | |
| Gila chub | Gila intermedia | Endangered | Wherever found | 11-02-2005 |
| Gila mayfly | Lachlania dencyanna | Under Review | Wherever found | |
| Gila monster lizard | Heloderma suspectum | Resolved Taxon | Utah DPS | |
| Gila monster lizard | Heloderma suspectum | Resolved Taxon | Wherever found | |
| Gila springsnail | Pyrgulopsis gilae | Resolved Taxon | Wherever found | |
| Gila topminnow (incl. Yaqui) | Poeciliopsis occidentalis | Endangered | Wherever found | 03-11-1967 |
| Gila trout | Oncorhynchus gilae | Threatened | Wherever found | 03-11-1967 |
| Gila Tryonia snail | Tryonia gilae | Under Review | Wherever found | |
| Gila Woodpecker | Melanerpes uropygialis | Species of Concern | Wherever found | |
| Gilded Flicker | Colaptes chrysoides | Species of Concern | Wherever found | |
| Gilman's buckwheat | Eriogonum gilmanii | Resolved Taxon | Wherever found | |
| Gilt Darter | Percina evides | Not Listed | | |
| Giraffe | Giraffa camelopardalis | Proposed Threatened | | |
| Giuliani's dubiraphian riffle beetle | Dubiraphia giulianii | Species of Concern | Wherever found | |
| Giuliani's dune scarab | Pseudocotalpa giulianii | Resolved Taxon | Wherever found | |
| Gizzard Shad | Dorosoma cepedianum | Not Listed | | |
| Glabrous allocarya | Plagiobothrys glaber | Resolved Taxon | Wherever found | |
| Glacier Bay water shrew | Sorex alaskanus | Species of Concern | Wherever found | |
| Glacier bear | Ursus americanus emmonsii | Resolved Taxon | Wherever found | |
| Gladiator elimia | Elimia hydei | Species of Concern | Wherever found | |
| Gladiator milk-vetch | Astragalus xiphoides | Species of Concern | Wherever found | |
| Glandular dwarf-flax | Hesperolinon adenophyllum | Species of Concern | Wherever found | |
| Glass Mountain coral-root | Hexalectris nitida | Species of Concern | Wherever found | |
| Glass Mountain rock-daisy | Perityle vitreomontana | Resolved Taxon | Wherever found | |
| Glaucous macaw | Anodorhynchus glaucus | Endangered | Wherever found | 06-14-1976 |
| Glaucous tauschia | Tauschia glauca | Resolved Taxon | Wherever found | |
| Glenwood nesosydne planthopper | Nesosydne cyrtandricola | Species of Concern | Wherever found | |
| Globose dune beetle | Coelus globosus | Species of Concern | Wherever found | |
| Glossy snake | arizona elegans | Species of Concern | Wherever found | |
| Glossy Wolfsnail | Euglandina texasiana | Resolved Taxon | Wherever found | |
| Goat Canyon cottonwood | Populus hinckleyana | Resolved Taxon | Wherever found | |
| Goat Cave Woodlandsnail | Ashmunella bequaerti | Resolved Taxon | Wherever found | |
| Goat Mountain woodlandsnail | Ashmunella harrisi | Resolved Taxon | Wherever found | |
| Goat Peak pika | Ochotona princeps nigrescens | Species of Concern | Wherever found | |
| Goddess Supercoil | Paravitrea alethia | Resolved Taxon | Wherever found | |
| Godfrey's blazingstar | Liatris provincialis | Species of Concern | Wherever found | |
| Godfrey's butterwort | Pinguicula ionantha | Threatened | | 07-12-1993 |
| Godfrey's golden aster | Chrysopsis godfreyi | Species of Concern | Wherever found | |
| Godfrey's spiderlily | Hymenocallis godfreyi | Species of Concern | Wherever found | |
| GodfreyÂ’s stitchwort | Minuartia godfreyi | Under Review | Wherever found | |
| Godfry's privet | Forestiera godfreyi | Status Undefined | | |
| Goeden's lepidostoman caddisfly | Lepidostoma astaneum | Species of Concern | Wherever found | |
| Goeldi's marmoset | Callimico goeldii | Endangered | Wherever found | 06-02-1970 |
| Goff's southeastern pocket gopher | Geomys pinetis goffi | Resolved Taxon | Wherever found | |
| Goldbeach western pocket gopher | Thomomys mazama helleri | Species of Concern | Wherever found | |
| Golden bladder-pod | Lesquerella aurea | Resolved Taxon | Wherever found | |
| Golden buckwheat | Eriogonum chrysops | Species of Concern | Wherever found | |
| Goldenbush | Isocoma arguta | Species of Concern | Wherever found | |
| Golden carpet | Gilmania luteola | Resolved Taxon | Wherever found | |
| golden-cheeked warbler | Setophaga chrysoparia | Endangered | Wherever found | 05-04-1990 |
| Golden conure | Aratinga guarouba | Threatened | Wherever found | 05-26-2020 |
| Golden coqui | Eleutherodactylus jasperi | Threatened | Wherever found | 11-11-1977 |
| Golden Eagle | Aquila chrysaetos | Species of Concern | Wherever found | |
| Golden eopenthes click beetle | Eopenthes auratus | Species of Concern | Wherever found | |
| Golden glade cress | Leavenworthia aurea | Resolved Taxon | Wherever found | |
| Golden-horned caddisfly | Neothremma genella | Species of Concern | Wherever found | |
| Golden langur | Trachypithecus (=Presbytis) geei | Endangered | Wherever found | 06-14-1976 |
| Golden orb | Quadrula aurea | Resolved Taxon | Wherever found | |
| golden paintbrush | Castilleja levisecta | Recovery | Wherever found | 06-11-1997 |
| Golden pebblesnail | Somatogyrus aureus | Species of Concern | Wherever found | |
| Golden Redhorse | Moxostoma erythrurum | Not Listed | | |
| Golden-rumped tamarin | Leontopithecus spp. | Endangered | Wherever found | 06-02-1970 |
| Goldenseal | Hydrastis canadensis | Resolved Taxon | Wherever found | |
| Golden sedge | Carex lutea | Endangered | Wherever found | 01-23-2002 |
| Golden Shiner | Notemigonus crysoleucas | Not Listed | | |
| Golden-shouldered parakeet | Psephotus chrysopterygius | Endangered | Wherever found | 06-02-1970 |
| Golden-spined hedgehog cactus | Echinocereus viridiflorus cylindricus | Species of Concern | Wherever found | |
| Golden-spined prickly-pear | Opuntia aureispina | Resolved Taxon | Wherever found | |
| Golden spruce dots | Arthonia cupressina | Species of Concern | | |
| Golden wave tickseed | Coreopsis intermedia | Species of Concern | Wherever found | |
| Golden White-eye | Cleptornis marchei | Species of Concern | Wherever found | |
| Golden-winged warbler | Vermivora chrysoptera | Under Review | Wherever found | |
| Goldeye | Hiodon alosoides | Not Listed | | |
| Goldfish | Carassius auratus | Not Listed | | |
| Goldline darter | Percina aurolineata | Threatened | Wherever found | 04-22-1992 |
| Gold rush hanging fly | Orbittacus obscurus | Species of Concern | Wherever found | |
| Goldstripe Darter | Etheostoma parvipinne | Not Listed | | |
| Goliath Frog | Conraua goliath | Threatened | Wherever found | 12-08-1994 |
| Gonzales tryonia | Tryonia circumstriata (=stocktonensis) | Endangered | Wherever found | 07-09-2013 |
| Goodding fameflower | Talinum gooddingii | Resolved Taxon | Wherever found | |
| Goodding's ash | Fraxinus gooddingii | Resolved Taxon | Wherever found | |
| Gooddings bladder-pod | Lesquerella gooddingii | Resolved Taxon | Wherever found | |
| Goodding''s onion | Allium gooddingii | Resolved Taxon | Wherever found | |
| Goodrich's Blazingstar | Mentzelia goodrichii | Resolved Taxon | Wherever found | |
| Goose Creek milkvetch | Astragalus anserinus | Resolved Taxon | Wherever found | |
| Goose Lake lamprey | Lampetra tridentata | Species of Concern | Goose Lake | |
| Goose Lake redband trout | Oncorhynchus mykiss ssp. | Species of Concern | Goose Lake | |
| Goose Lake sucker | Catostomus occidentalis lacusanserinus | Species of Concern | Wherever found | |
| Goose Lake tui chub | Siphateles bicolor thalassinus | Status Undefined | | |
| Goose Valley pebblesnail | Fluminicola anserinus | Resolved Taxon | Wherever found | |
| Gooty Ornamental Tarantula | Poecilotheria metallica | Under Review | Wherever found | |
| Gopher Frog | Lithobates capito | Under Review | Wherever found | |
| Gopher tortoise | Gopherus polyphemus | Resolved Taxon | Eastern DPS | |
| Gopher tortoise | Gopherus polyphemus | Threatened | Western DPS | 07-07-1987 |
| Goral | Naemorhedus goral | Endangered | Wherever found | 06-14-1976 |
| gorge filmy fern | Hymenophyllum tayloriae | Species of Concern | Wherever found | |
| Gorge fleabane | Erigeron oreganus | Species of Concern | Wherever found | |
| Gorge leafy liverwort | Plagiochila caduciloba | Status Undefined | | |
| Gorge moss | Bryocrumia vivicolor | Species of Concern | Wherever found | |
| Gorgeted wood-quail | Odontophorus strophium | Endangered | Wherever found | 11-29-2013 |
| Gorilla | Gorilla gorilla | Endangered | Wherever found | 06-02-1970 |
| Gorman aster | Eucephalus gormanii | Species of Concern | Wherever found | |
| Gould's mouse | Pseudomys gouldii | Endangered | Wherever found | 06-04-1973 |
| Government Canyon Bat Cave meshweaver | Cicurina vespera | Endangered | Wherever found | 12-26-2000 |
| Government Canyon Bat Cave spider | Tayshaneta microps | Endangered | Wherever found | 12-26-2000 |
| Gowen cypress | Cupressus goveniana ssp. goveniana | Threatened | Wherever found | 08-12-1998 |
| Graceful peperomia | Peperomia obovatilimba | Resolved Taxon | Wherever found | |
| Grace's Warbler | Setophaga graciae | Species of Concern | Wherever found | |
| Gracile anchotefflus ground beetle | Anchotefflus gracilis | Species of Concern | Wherever found | |
| Grady's cave amphipod | Stygobromus gradyi | Resolved Taxon | Wherever found | |
| Graham beardtongue | Penstemon grahamii | Resolved Taxon | Wherever found | |
| Graham catseye | Cryptantha grahamii | Resolved Taxon | Wherever found | |
| Graham Mountains long-tailed vole | Microtus longicaudus leucophaeus | Resolved Taxon | Wherever found | |
| Graham Mountains pocket gopher | Thomomys umbrinus grahamensis | Resolved Taxon | Wherever found | |
| Graham's Columbine | Aquilegia grahamii | Resolved Taxon | Wherever found | |
| Graham's harvestman | Banksula grahami | Status Undefined | Wherever found | |
| Graham's twinpod | Physaria grahamii | Resolved Taxon | Wherever found | |
| Grand Canyon catchfly | Silene rectiramea | Resolved Taxon | Wherever found | |
| Grand Canyon cave pseudoscorpion | Archeolarca cavicola | Under Review | Wherever found | |
| Grand Canyon rose | Rosa stellata abyssa | Species of Concern | Wherever found | |
| Grand Cayman ground iguana | Cyclura lewisi | Endangered | Wherever found | 06-22-1983 |
| Grande stripetail stonefly | Isoperla jewetti | Resolved Taxon | Wherever found | |
| Grandfather Mountain crayfish | Cambarus eeseeohensis | Status Undefined | Wherever found | |
| Grand Junction catseye | Cryptantha aperta | Species of Concern | Wherever found | |
| Grand Junction milk-vetch | Astragalus linifolius | Resolved Taxon | Wherever found | |
| Grand Wash springsnail | Pyrgulopsis bacchus | Under Review | Wherever found | |
| Granite Dome Goldenrod | Solidago simulans | Species of Concern | | |
| Granite night lizard | Xantusia henshawi | Species of Concern | Wherever found | |
| Granite pebblesnail | Somatogyrus hinkleyi | Species of Concern | Wherever found | |
| Granite spiny lizard | sceloporus orcutti | Species of Concern | Wherever found | |
| Grapevine Springs elongate tryonia | Tryonia margae | Species of Concern | Wherever found | |
| Grapevine Springs squat tryonia | Tryonia rowlandsi | Species of Concern | Wherever found | |
| Grasshopper Sparrow | Ammodramus savannarum | Species of Concern | Wherever found | |
| Grasshopper Sparrow | Ammodramus savannarum ammolegus | Species of Concern | Wherever found | |
| Grasshopper Sparrow | Ammodramus savannarum perpallidus | Species of Concern | Wherever found | |
| Grasshopper Sparrow | Ammodramus savannarum pratensis | Species of Concern | | |
| Grass milk-vetch | Astragalus chloodes | Resolved Taxon | Wherever found | |
| Grass owl | Tyto longimembris | Resolved Taxon | Wherever found | |
| Grass Pickerel | Esox americanus | Not Listed | | |
| Grass Valley speckled dace | Rhinichthys osculus reliquus | Resolved Taxon | Wherever found | |
| Grassy Cove cave beetle | Pseudanophthalmus jonesi | Species of Concern | Wherever found | |
| Grassy Creek Cave spider | Nesticus dilutus | Species of Concern | Wherever found | |
| Grated tryonia | Tryonia clathrata | Resolved Taxon | Wherever found | |
| Gravel Chub | Erimystax x-punctatus | Not Listed | | |
| Gray-backed Tern | Onychoprion lunatus | Species of Concern | | |
| Gray-banded king snake | Lampropeltis mexicana alterna | Resolved Taxon | Wherever found | |
| Gray bat | Myotis grisescens | Endangered | Wherever found | 04-28-1976 |
| gray cat's-eye | Oreocarya leucophaea | Status Undefined | | |
| Gray-checkered whiptail | Cnemidophorus dixoni | Species of Concern | Wherever found | |
| Gray (=entellus) langur | Semnopithecus (=Presbytis) entellus | Endangered | Wherever found | 06-14-1976 |
| Gray-faced Petrel | Pterodroma gouldi | Species of Concern | | |
| Gray-footed Chipmunk | Tamias canipes | Species of Concern | Wherever found | |
| grayfoot mantleslug | philomycus bisdodus | Resolved Taxon | Wherever found | |
| Gray fox | Urocyon cinereoargenteus ssp. cinereoargenteus | Status Undefined | Wherever found | |
| Gray-headed Chickadee | Poecile cinctus | Species of Concern | | |
| Gray-headed Chickadee | Poecile cinctus lathami | Species of Concern | | |
| Gray Nightjar | Caprimulgus jotaka | Species of Concern | | |
| Gray oechalia stink bug | Oechalia grisea | Species of Concern | Wherever found | |
| Gray redhorse | moxostoma congestum | Species of Concern | Wherever found | |
| Gray rock-daisy | Perityle cinerea | Resolved Taxon | Wherever found | |
| Gray's lily | Lilium grayi | Species of Concern | Wherever found | |
| Grayson crayfish ostracod | Ascetocthere cosmeta | Species of Concern | Wherever found | |
| Gray's saxifrage | Saxifraga caroliniana | Species of Concern | Wherever found | |
| Gray vireo | Vireo vicinior | Species of Concern | Wherever found | |
| Gray whale | Eschrichtius robustus | Endangered | Western North Pacific DPS See 50 CFR 224.101 | 06-02-1970 |
| Gray whale | Eschrichtius robustus | Recovery | Eastern North Pacific Ocean--coastal and Bering, Beaufort, and Chukchi Seas | 06-16-1994 |
| Gray wolf | Canis lupus | Endangered | U.S.A.: All of AL, AR, CA, CO, CT, DE, FL, GA, IA, IN, IL, KS, KY, LA, MA, MD, ME, MI, MO, MS, NC, ND, NE, NH, NJ, NV, NY, OH, OK, PA, RI, SC, SD, TN, TX, VA, VT, WI, and WV; and portions of AZ, NM, OR, UT, and WA as follows: (1) Northern AZ (that portion north of the centerline of Interstate Highway 40); (2) Northern NM (that portion north of the centerline of Interstate Highway 40); (3) Western OR (that portion of OR west of the centerline of Highway 395 and Highway 78 north of Burns Junction and that portion of OR west of the centerline of Highway 95 south of Burns Junction); (4) Most of Utah (that portion of UT south and west of the centerline of Highway 84 and that portion of UT south of Highway 80 from Echo to the UT/WY Stateline); and (5) Western WA (that portion of WA west of the centerline of Highway 97 and Highway 17 north of Mesa and that portion of WA west of the centerline of Highway 395 south of Mesa). Mexico. | 03-09-1978 |
| Gray wolf | Canis lupus | Experimental Population, Non-Essential | CO experimental population | |
| Gray wolf | Canis lupus | Recovery | Northern Rocky Mountain Distinct Population Segment: Montana, Idaho, Wyoming, eastern Washington, eastern Oregon, and north central Utah | 03-09-1978 |
| Gray wolf | Canis lupus | Resolved Taxon | Western Gray Wolf Population + AZ: AZ, CA, CO, ID, MT, NV, OR, UT, WY, WA | |
| Gray wolf | Canis lupus | Resolved Taxon | Western Gray Wolf Population: CA, CO, ID, MT, NV, OR, UT, WY, WA | |
| Gray wolf | Canis lupus | Threatened | U.S.A. (MN) | 03-09-1978 |
| Great Barracuda, Kaku | Sphyraena barracuda | Not Listed | | |
| Great Basin collared lizard | Crotaphytus bicinctores | Not Listed | | |
| Great Basin fishhook cactus | Sclerocactus pubispinus | Resolved Taxon | Wherever found | |
| Great Basin ramshorn | Helisoma newberryi | Resolved Taxon | Wherever found | |
| Great Basin redband trout | Oncorhynchus mykiss ssp. | Resolved Taxon | Wherever found | |
| Great Black-backed Gull | Larus marinus | Species of Concern | Wherever found | |
| Great blue heron | Ardea herodias | Species of Concern | Wherever found | |
| Great Blue Heron | Ardea herodias fannini | Species of Concern | | |
| Great Blue Heron | Ardea herodias occidentalis | Species of Concern | | |
| Great Cormorant | Phalacrocorax carbo | Species of Concern | Wherever found | |
| Great Crested Flycatcher | Myiarchus crinitus | Species of Concern | Wherever found | |
| Greater Adams Cave beetle | Pseudanophthalmus pholeter | Resolved Taxon | Wherever found | |
| Greater adjutant | Leptoptilos dubius | Endangered | Wherever found | 09-12-2011 |
| Greater Monkey-Faced Bat | Pteralopex flanneryi | Under Review | Wherever found | |
| Greater redhorse | Moxostoma valenciennesi | Species of Concern | Wherever found | |
| Greater sage-grouse | Centrocercus urophasianus | Proposed Threatened | Bi-State | |
| Greater sage-grouse | Centrocercus urophasianus | Resolved Taxon | Western subspecies | |
| Greater sage-grouse | Centrocercus urophasianus | Resolved Taxon | Wherever found | |
| Greater Saint Croix Skink | Spondylurus magnacruzae | Resolved Taxon | Wherever found | |
| Greater Sandhill Crane | Grus canadensis tabida | Status Undefined | Wherever found | |
| Greater Virgin Islands Skink | Spondylurus spilonotus | Resolved Taxon | Wherever found | |
| Greater western mastiff-bat | Eumops perotis californicus | Species of Concern | Wherever found | |
| Great Frigatebird | Fregata minor | Species of Concern | | |
| Great Frigatebird | Fregata minor palmerstoni | Species of Concern | | |
| Great green macaw | Ara ambiguus | Endangered | Wherever found | 11-02-2015 |
| Great horned owl | Bubo virginianus | Not Listed | | |
| Great Indian bustard | Ardeotis (=Choriotis) nigriceps | Endangered | Wherever found | 06-02-1970 |
| Great Indian rhinoceros | Rhinoceros unicornis | Endangered | Nepal, India | 12-02-1970 |
| Great Plains Toad | Anaxyrus cognatus | Not Listed | | |
| Great Sand Dunes Anthicid Beetle | Amblyderus werneri | Resolved Taxon | Wherever found | |
| Great Sand Dunes Tiger Beetle | Cicindela theatina | Resolved Taxon | Wherever found | |
| Great Shearwater | Puffinus gravis | Species of Concern | Wherever found | |
| Great Skua | Stercorarius skua | Species of Concern | | |
| Greenback Cutthroat trout | Oncorhynchus clarkii stomias | Threatened | Wherever found | 03-11-1967 |
| Greenbanded 'ohe'ohe leafroller | Spheterista pterotropiana | Species of Concern | Wherever found | |
| Green blossom (pearlymussel) | Epioblasma torulosa gubernaculum | Extinction | Wherever found | 06-14-1976 |
| Greenbrier Cave amphipod | Stygobromus emarginatus | Resolved Taxon | Wherever found | |
| Greenbrier Cave crayfish | Cambarus nerterius | Under Review | Wherever found | |
| Greenbrier cavesnail | Fontigens turritella | Species of Concern | Wherever found | |
| Greenbrier Valley cave beetle | Pseudanophthalmus fuscus fuscus | Species of Concern | Wherever found | |
| Greenbrier Valley cave pseudoscorpion | Kleptochthonius henroti | Species of Concern | Wherever found | |
| Green carposinid moth | Carposina viridis | Species of Concern | Wherever found | |
| Green Crab | Carcinus maenas | Not Listed | | |
| Greene's mariposa lily | Calochortus greenei | Species of Concern | Wherever found | |
| Greene's popcornflower | Plagiobothrys greenei | Species of Concern | Wherever found | |
| Greenest tiger beetle | Cicindela tranquebarica viridissima | Species of Concern | Wherever found | |
| Greene's tuctoria | Tuctoria greenei | Endangered | Wherever found | 03-26-1997 |
| Green fiddleneck | Amsinckia vernicosa | Resolved Taxon | Wherever found | |
| Greenfield rams-horn | Taphius eucosmius eucosmius | Resolved Taxon | Wherever found | |
| Green floater | Lasmigona subviridis | Proposed Threatened | Wherever found | |
| Greenflower nipple cactus | Mammillaria viridiflora | Resolved Taxon | Wherever found | |
| Green Frog | Lithobates clamitans | Not Listed | | |
| Green Frog | Lithobates clamitans | Not Listed | | |
| Green glyphodes moth | Glyphodes exaula | Species of Concern | Wherever found | |
| Greenhorn adobe-lily | Fritillaria striata | Resolved Taxon | Wherever found | |
| Greenhorn fritillary | Fritillaria brandegeei | Resolved Taxon | Wherever found | |
| Greenland white-tailed eagle | Haliaeetus albicilla groenlandicus | Endangered | Wherever found | 06-14-1976 |
| Green liveforever | Dudleya virens | Species of Concern | Wherever found | |
| Greenman's desert-parsley | Lomatium greenmanii | Species of Concern | Wherever found | |
| Greenman's hexalectris | Hexalectris grandiflora | Resolved Taxon | Wherever found | |
| Green Parakeet | Aratinga holochlora | Species of Concern | Wherever found | |
| Green Pitcher Plant | Sarracenia oreophila | Endangered | Wherever found | 10-21-1979 |
| Green salamander | Aneides aeneus | Status Undefined | Wherever found | |
| Green sawfish | Pristis zijsron | Endangered | Wherever found | 01-12-2015 |
| Greensboro burrowing crayfish | Cambarus catagius | Resolved Taxon | Wherever found | |
| Green sea turtle | Chelonia mydas | Endangered | Green sea turtles originating from the Central South Pacific Ocean, bounded by the following coordinates: 9 degrees N., 175 degrees W. in the northwest; 9 degrees N., 125 degrees W. in the northeast; 40 degrees S., 96 degrees W. in the southeast; 40 degrees S., 176 degrees E. in the southwest; and 13 degrees S., 171 degrees E. in the west | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Endangered | Green sea turtles originating from the Central West Pacific Ocean, bounded by the following coordinates: 41 degrees N., 146 degrees E. in the northwest; 41 degrees N., 169 degrees E. in the northeast; 9 degrees N., 175 degrees W. in the east; 13 degrees S., 171 degrees E. in the southeast; along the northern coast of the island of New Guinea; and 4.5 degrees N., 129 degrees E. in the west | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Endangered | Green sea turtles originating from the Mediterranean Sea, bounded by 5.5 degrees W. Long. in the west | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the Central North Pacific Ocean, bounded by the following coordinates: 41 degrees N., 169 degrees E. in the northwest; 41 degrees N., 143 degrees W. in the northeast; 9 degrees N., 125 degrees W. in the southeast; and 9 degrees N., 175 degrees W. in the southwest Pacific coast of Mexico | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the Eastern Indian and Western Pacific Oceans, bounded by the following lines and coordinates: 41 degrees N. Lat. in the north, 41 degrees N., 146 degrees E. in the northeast; 4.5 degrees N., 129 degrees E. in the southeast; along the southern coast of the island of New Guinea; along the western coast of Australia (west of 142 degrees E. Long.); 40 degrees S. Lat. in the south; and 84 degrees E. Long. in the east | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the East Pacific Ocean, bounded by the following lines and coordinates: 41 degrees N., 143 degrees W. in the northwest; 41 degrees N. Lat. in the north; along the western coasts of the Americas; 40 degrees S. Lat. in the south; and 40 degrees S., 96 degrees W. in the southwest | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the North Atlantic Ocean, bounded by the following lines and coordinates: 48 degrees N. Lat. in the north, along the western coasts of Europe and Africa (west of 5.5 degrees W. Long.); north of 19 degrees N. Lat. in the east; bounded by 19 degrees N., 65.1 degrees W. to 14 degrees N., 65.1 degrees W. then 14 degrees N., 77 degrees W. in the south and west; and along the eastern coasts of the Americas (north of 7.5 degrees N., 77 degrees W.) | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the North Indian Ocean, bounded by: Africa and Asia in the west and north; 84 degrees E. Long. in the east; and the equator in the south | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the South Atlantic Ocean, bounded by the following lines and coordinates: along the northern and eastern coasts of South America (east of 7.5 degrees N., 77 degrees W.); 14 degrees N., 77 degrees W. to 14 degrees N., 65.1 degrees W. to 19 degrees N., 65.1 degrees W. in the north and west; 19 degrees N. Lat. in the northeast; 40 degrees S., 19 degrees E. in the southeast; and 40 degrees S. Lat. in the south | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the Southwest Indian Ocean, bounded by the following lines: the equator to the north; 84 degrees E. Long. to the east; 40 degrees S. Lat. to the south; and 19 degrees E. Long (and along the eastern coast of Africa) in the west | 05-06-2016 |
| Green sea turtle | Chelonia mydas | Threatened | Green sea turtles originating from the Southwest Pacific Ocean, bounded by the following lines and coordinates: along the southern coast of the island of New Guinea and the Torres Strait (east of 142 degrees E Long.); 13 degrees S., 171 degrees E. in the northeast; 40 degrees S., 176 degrees E. in the southeast; and 40 degrees S., 142 degrees E. in the southwest | 05-06-2016 |
| Greenside Darter | Etheostoma blennioides | Not Listed | | |
| Green Springs Mountain farulan caddisfly | Farula davisi | Species of Concern | Wherever found | |
| green sturgeon | Acipenser medirostris | Not Listed | Wherever found | |
| green sturgeon | Acipenser medirostris | Threatened | Southern DPS - See 50 CFR 223.102 | 06-06-2006 |
| Green Sunfish | Lepomis cyanellus | Not Listed | | |
| Greensword | Argyroxiphium virescens | Resolved Taxon | Wherever found | |
| Green-tailed Towhee | Pipilo chlorurus | Species of Concern | Wherever found | |
| Greenthroat darter | Etheostoma lepidum | Resolved Taxon | Wherever found | |
| Green-tinged paintbrush | Castilleja chlorotica | Species of Concern | Wherever found | |
| Green Toad | Anaxyrus debilis | Not Listed | | |
| Greenwell's long-horned beetle | Plagithmysus greenwelli | Species of Concern | Wherever found | |
| Green-winged teal | Anas crecca | Status Undefined | Wherever found | |
| Greenwood's Heath goldenrod | Ericameria lignumviridis | Resolved Taxon | Wherever found | |
| Grenada gray-fronted dove | Leptotila rufaxilla wellsi | Endangered | Wherever found | 06-02-1970 |
| Grenada hook-billed kite | Chondrohierax uncinatus mirus | Endangered | Wherever found | 06-02-1970 |
| Grevy's zebra | Equus grevyi | Threatened | Wherever found | 09-20-1979 |
| grey-cheeked parakeet | Brotogeris pyrrhoptera | Under Review | Wherever found | |
| Grey-headed blackbird | Turdus poliocephalus poliocephalus | Resolved Taxon | Wherever found | |
| Grey-necked rockfowl | Picathartes oreas | Endangered | Wherever found | 06-02-1970 |
| Grey's silverspot | Speyeria atlantis greyi | Species of Concern | Wherever found | |
| Grey-winged cotinga | Tijuca condita | Status Undefined | Wherever found | |
| Griffith's saltbush | Atriplex griffithsii | Resolved Taxon | Wherever found | |
| Grimes vetchling | Lathyrus grimesii | Resolved Taxon | Wherever found | |
| Grimy ivesia | Ivesia rhypara rhypara | Resolved Taxon | Wherever found | |
| Grizzled skipper | Pyrgus centaureae | Species of Concern | Wherever found | |
| Grizzly bear | Ursus arctos horribilis | Experimental Population, Non-Essential | North Cascades Ecosystem Non-Essential Experimental Population | |
| Grizzly bear | Ursus arctos horribilis | Threatened | U.S.A., conterminous (lower 48) States, except where listed as an experimental population | 07-28-1975 |
| Grotto Sculpin | Cottus specus | Endangered | Wherever found | 10-25-2013 |
| Ground parrot | Pezoporus wallicus | Endangered | Wherever found | 06-04-1973 |
| Ground-spreading tick-trefoil | Desmodium humifusum | Species of Concern | Wherever found | |
| Grubbs' cave pseudoscorpion | Aphrastochthonius grubbsi | Species of Concern | Wherever found | |
| Guaco | Mikania stevensiana | Resolved Taxon | Wherever found | |
| Guadalupe bass | Micropterus treculii | Species of Concern | Wherever found | |
| Guadalupe cave pseudoscorpion | Archeolarca guadalupensis | Resolved Taxon | Wherever found | |
| Guadalupe Darter | Percina apristis | Not Listed | | |
| Guadalupe Fatmucket | Lampsilis bergmanni | Endangered | | 07-05-2024 |
| Guadalupe fescue | Festuca ligulata | Endangered | Wherever found | 10-10-2017 |
| Guadalupe fur seal | Arctocephalus townsendi | Threatened | Wherever found | 03-11-1967 |
| Guadalupe Island lupine | Lupinus guadalupensis | Species of Concern | Wherever found | |
| Guadalupe Mountain necklacepod | Sophora gypsophila | Not Listed | | |
| Guadalupe Mountain sedge | carex mckittrickensis | Resolved Taxon | Wherever found | |
| Guadalupe Mountains mescal bean | Sophora gypsophila guadalupensis | Resolved Taxon | Wherever found | |
| Guadalupe Mountains tiger beetle | Cicindela politula petrophila | Resolved Taxon | Wherever found | |
| Guadalupe Mountain violet | Viola guadalupensis | Resolved Taxon | Wherever found | |
| Guadalupe Murrelet | Synthliboramphus hypoleucus | Resolved Taxon | Wherever found | |
| Guadalupe Orb | Cyclonaias necki | Endangered | Wherever Found | 07-05-2024 |
| Guadalupe pincushion cactus | Escobaria guadalupensis | Resolved Taxon | Wherever found | |
| Guadalupe roundnose Minnow | Dionda nigrotaeniata | Species of Concern | Wherever found | |
| Guadalupe smooth aster | Aster laevis guadalupensis | Species of Concern | Wherever found | |
| Guadalupe southern pocket gopher | Thomomys umbrinus guadalupensis | Species of Concern | Wherever found | |
| Guadalupe valerian | Valeriana texana | Resolved Taxon | Wherever found | |
| Guadeloupe house wren | Troglodytes aedon guadeloupensis | Endangered | Wherever found | 06-02-1970 |
| Guadelupe Woodlandsnail | Ashmunella carlsbadensis | Under Review | Wherever found | |
| Guajon | Eleutherodactylus cooki | Threatened | Wherever found | 06-11-1997 |
| Gualala Roach | Hesperoleucus parvipinnis | Species of Concern | Wherever found | |
| Guam broadbill | Myiagra freycineti | Extinction | Wherever found | 08-27-1984 |
| Guam kingfisher | Todiramphus cinnamominus | Endangered | Wherever found | 08-27-1984 |
| Guam kingfisher | Todiramphus cinnamominus | Experimental Population, Non-Essential | | 05-04-2023 |
| Guam rail | Gallirallus owstoni | Endangered | Wherever found, except where listed as an experimental population | 04-11-1984 |
| Guam rail | Gallirallus owstoni | Experimental Population, Non-Essential | Rota | 10-30-1989 |
| Guam rufous-fronted fantail | Rhipidura rufifrons uraniae | Resolved Taxon | Wherever found | |
| Guam tree snail | Partula radiolata | Endangered | Wherever found | 11-02-2015 |
| Guam white-throated ground-dove | Gallicolumba xanthonura xanthonura | Resolved Taxon | Wherever found | |
| Guatemalan Fir (=pinabete) | Abies guatemalensis | Threatened | Wherever found | 12-10-1979 |
| Guatemalan jaguarundi | Herpailurus (=Felis) yagouaroundi fossata | Endangered | Mexico,Nicaragua | 06-14-1976 |
| Guizhou snub-nosed monkey | Rhinopithecus brelichi | Endangered | Wherever found | 09-27-1990 |
| Gulf beach sunflower | Helianthus debilis vestitus | Species of Concern | Wherever found | |
| Gulf Coast hog-nosed skunk | Conepatus leuconotus texensis | Resolved Taxon | Wherever found | |
| Gulf Coast jaguarundi | Puma yagouaroundi cacomitli | Endangered | Wherever found | 06-14-1976 |
| Gulfcoast lupine | Lupinus westianus | Species of Concern | Wherever found | |
| Gulf Coast Smooth Softshell Turtle | Apalone mutica calvata | Not Listed | | |
| Gulf Coast solitary bee | Hesperapis oraria | Not Listed | | |
| Gulf Coast Waterdog | Necturus beyeri | Not Listed | | |
| Gulf Flounder | Paralichthys albigutta | Not Listed | | |
| Gulf Grouper | Mycteroperca jordani | Endangered | | |
| Gulf Hammock dwarf siren | Pseudobranchus striatus lustricolus | Under Review | Wherever found | |
| Gulf Menhaden | Brevoortia patronus | Not Listed | | |
| Gulf moccasinshell | Medionidus penicillatus | Endangered | Wherever found | 03-16-1998 |
| Gulf of Mexico Bryde's Whale | Balaenoptera edeni | Endangered | | |
| Gulf salt marsh snake | Nerodia clarkii | Species of Concern | Wherever found | |
| Gulf sturgeon | Acipenser oxyrinchus (=oxyrhynchus) desotoi | Threatened | Wherever found | 09-30-1991 |
| Gulf Sweet pitcherplant | Sarracenia rubra ssp. gulfensis | Under Review | Wherever found | |
| Gull-billed Tern | Gelochelidon nilotica | Species of Concern | Wherever found | |
| Gumbo milk-vetch | Astragalus ampullarius | Species of Concern | Wherever found | |
| Gunnison Island kangaroo rat | Dipodomys microps alfredi | Species of Concern | Wherever found | |
| Gunnison milk-vetch | Astragalus anisus | Species of Concern | Wherever found | |
| Gunnison sage-grouse | Centrocercus minimus | Threatened | Wherever found | 12-22-2014 |
| Gunnison's prairie dog | Cynomys gunnisoni | Resolved Taxon | central and south-central Colorado, north-central New Mexico | |
| Gurney's pitta | Pitta gurneyi | Endangered | Wherever found | 01-16-2008 |
| Guthrie's (=Pyne's) ground-plum | Astragalus bibullatus | Endangered | Wherever found | 09-26-1991 |
| Guyandotte River crayfish | Cambarus veteranus | Endangered | Wherever found | 05-09-2016 |
| Gypsum milk-vetch | Astragalus gypsodes | Resolved Taxon | Wherever found | |
| Gypsum scalebroom | Lepidospartum burgessii | Species of Concern | Wherever found | |
| Gypsum Valley Cryptantha | Cryptantha gypsophila | Resolved Taxon | Wherever found | |
| Gypsum wild-buckwheat | Eriogonum gypsophilum | Threatened | Wherever found | 01-19-1981 |
| Haas' `iliahi long-horned beetle | Plagithmysus haasi | Species of Concern | Wherever found | |
| Hacheta Grande woodlandsnail | Ashmunella hebardi | Resolved Taxon | Wherever found | |
| Haddleton lampmussel | Lampsilis haddletoni | Species of Concern | Wherever found | |
| Haddock's rhyacophilan caddisfly | Rhyacophila haddocki | Species of Concern | Wherever found | |
| haha | Cyanea crispa | Endangered | Wherever found | 03-28-1994 |
| haha | Cyanea dunbariae | Endangered | Wherever found | 10-10-1996 |
| haha | Cyanea duvalliorum | Endangered | Wherever found | 06-27-2013 |
| haha | Cyanea gibsonii | Endangered | Wherever found | 09-20-1991 |
| haha | Cyanea magnicalyx | Endangered | Wherever found | 06-27-2013 |
| haha | Cyanea maritae | Endangered | Wherever found | 06-27-2013 |
| haha | Cyanea mauiensis | Endangered | Wherever found | 06-27-2013 |
| haha | Cyanea munroi | Endangered | Wherever found | 06-27-2013 |
| Haha | Cyanea acuminata | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea asarifolia | Endangered | Wherever found | 02-25-1994 |
| Haha | Cyanea asplenifolia | Endangered | Wherever found | 06-27-2013 |
| Haha | Cyanea calycina | Endangered | Wherever found | 10-18-2012 |
| Haha | Cyanea copelandii ssp. copelandii | Endangered | Wherever found | 03-04-1994 |
| Haha | Cyanea copelandii ssp. haleakalaensis | Endangered | Wherever found | 09-03-1999 |
| Haha | Cyanea dolichopoda | Endangered | Wherever found | 05-13-2010 |
| Haha | Cyanea eleeleensis | Endangered | Wherever found | 05-13-2010 |
| Haha | Cyanea glabra | Endangered | Wherever found | 09-03-1999 |
| Haha | Cyanea grimesiana ssp. grimesiana | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea grimesiana ssp. obatae | Endangered | Wherever found | 06-27-1994 |
| Haha | Cyanea hamatiflora ssp. carlsonii | Endangered | Wherever found | 03-04-1994 |
| Haha | Cyanea hamatiflora ssp. hamatiflora | Endangered | Wherever found | 09-03-1999 |
| Haha | Cyanea humboldtiana | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea kolekoleensis | Endangered | Wherever found | 05-13-2010 |
| Haha | Cyanea koolauensis | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea kuhihewa | Endangered | Wherever found | 05-13-2010 |
| Haha | Cyanea kunthiana | Endangered | Wherever found | 06-27-2013 |
| Haha | Cyanea lanceolata | Endangered | Wherever found | 10-18-2012 |
| Haha | Cyanea lobata | Endangered | Wherever found | 05-15-1992 |
| Haha | Cyanea longiflora | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea longissima | Species of Concern | Wherever found | |
| Haha | Cyanea mannii | Endangered | Wherever found | 10-08-1992 |
| Haha | Cyanea marksii | Endangered | Wherever found | 11-29-2013 |
| Haha | Cyanea mceldowneyi | Endangered | Wherever found | 05-15-1992 |
| Haha | Cyanea obtusa | Endangered | Wherever found | 06-27-2013 |
| Haha | Cyanea pinnatifida | Endangered | Wherever found | 10-29-1991 |
| Haha | Cyanea procera | Endangered | Wherever found | 10-08-1992 |
| Haha | Cyanea profuga | Endangered | Wherever found | 06-27-2013 |
| Haha | Cyanea pseudofauriei | Resolved Taxon | Wherever found | |
| Haha | Cyanea purpurellifolia | Endangered | Wherever found | 10-18-2012 |
| Haha | Cyanea recta | Threatened | Wherever found | 10-10-1996 |
| Haha | Cyanea remyi | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea rivularis | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea shipmanii | Endangered | Wherever found | 03-04-1994 |
| Haha | Cyanea stictophylla | Endangered | Wherever found | 03-04-1994 |
| Haha | Cyanea st.-johnii | Endangered | Wherever found | 10-10-1996 |
| Haha | Cyanea superba | Endangered | Wherever found | 09-11-1991 |
| Haha | Cyanea truncata | Endangered | Wherever found | 03-28-1994 |
| Haha | Cyanea undulata | Endangered | Wherever found | 09-20-1991 |
| haha nui | Cyanea horrida | Endangered | Wherever found | 06-27-2013 |
| Hahnel's Amazonian swallowtail butterfly | Parides hahneli | Endangered | Wherever found | 01-09-2025 |
| Hairy halberd fern | Tectaria coriandrifolia | Species of Concern | Wherever found | |
| Hairy Lemmon's needlegrass | Stipa lemmonii pubescens | Resolved Taxon | Wherever found | |
| Hairy Orcutt grass | Orcuttia pilosa | Endangered | Wherever found | 03-26-1997 |
| Hairy-peduncled beaked-rush | Rhynchospora crinipes | Resolved Taxon | Wherever found | |
| Hairy pod vetch | Vicia minutiflora | Resolved Taxon | Wherever found | |
| Hairy rattleweed | Baptisia arachnifera | Endangered | Wherever found | 05-27-1978 |
| Hairy stickleaf | Mentzelia hirsutissima stenophylla | Resolved Taxon | Wherever found | |
| Hairy-Tailed Bats | Lasiurus sp. | Not Listed | | |
| Hairy-Tailed Bats | Lasiurus sp. | Not Listed | | |
| hairy water flea | Dumontia oregonensis | Species of Concern | Wherever found | |
| Hairy wild indigo | Baptisia calycosa villosa | Species of Concern | Wherever found | |
| hairy woodpecker | Picoides villosus | Status Undefined | Wherever found | |
| Haitian solenodon | Solenodon paradoxus | Endangered | Wherever found | 06-02-1970 |
| haiwale | Cyrtandra ferripilosa | Endangered | Wherever found | 06-27-2013 |
| haiwale | Cyrtandra nanawaleensis | Endangered | Wherever found | 11-29-2013 |
| haiwale | Cyrtandra wagneri | Endangered | Wherever found | 11-29-2013 |
| Haiwale | Cyrtandra gracilis | Endangered | Wherever found | 10-18-2012 |
| Haiwale | Cyrtandra paliku | Endangered | Wherever found | 05-13-2010 |
| Haiwale | Cyrtandra waiolani | Endangered | Wherever found | 10-18-2012 |
| Ha`iwale | Cyrtandra biserrata | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra crenata | Endangered | Wherever found | 03-28-1994 |
| Ha`iwale | Cyrtandra dentata | Endangered | Wherever found | 10-10-1996 |
| Ha`iwale | Cyrtandra filipes | Endangered | Wherever found | 06-27-2013 |
| Ha`iwale | Cyrtandra giffardii | Endangered | Wherever found | 03-04-1994 |
| Ha`iwale | Cyrtandra halawensis | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra hematos | Endangered | Wherever found | 10-31-2016 |
| Ha`iwale | Cyrtandra kaulantha | Endangered | Wherever found | 10-18-2012 |
| Ha`iwale | Cyrtandra kealiae | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra limahuliensis | Threatened | Wherever found | 02-25-1994 |
| Ha`iwale | Cyrtandra lydgatei | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra macrocalyx | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra menziesii | Resolved Taxon | Wherever found | |
| Ha`iwale | Cyrtandra munroi | Endangered | Wherever found | 05-15-1992 |
| Ha`iwale | Cyrtandra oenobarba | Endangered | Wherever found | 05-13-2010 |
| Ha`iwale | Cyrtandra oxybapha | Endangered | Wherever found | 06-27-2013 |
| Ha`iwale | Cyrtandra pickeringii | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra polyantha | Endangered | Wherever found | 03-28-1994 |
| Ha`iwale | Cyrtandra pruinosa | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra sandwicensis | Species of Concern | Wherever found | |
| Ha`iwale | Cyrtandra sessilis | Endangered | Wherever found | 10-18-2012 |
| Ha`iwale | Cyrtandra subumbellata | Endangered | Wherever found | 10-10-1996 |
| Ha`iwale | Cyrtandra tintinnabula | Endangered | Wherever found | 03-04-1994 |
| Ha`iwale | Cyrtandra viridiflora | Endangered | Wherever found | 10-10-1996 |
| Hala pepe | Dracaena fernaldii | Endangered | Wherever found | 06-27-2013 |
| Hala pepe | Dracaena forbesii | Endangered | Wherever found | 10-18-2012 |
| Hala pepe | Dracaena konaensis | Endangered | Wherever found | 10-10-1996 |
| Haleakala deropristus ground beetle | Deropristus deroderus | Species of Concern | Wherever found | |
| Haleakala ectemnius sphecid wasp | Ectemnius haleakalae | Species of Concern | Wherever found | |
| Haleakala flightless thyrocopa moth | Thyrocopa apatela | Species of Concern | Wherever found | |
| Haleakala micromus brown lacewing | Micromus haleakalae | Species of Concern | Wherever found | |
| Haleakala pseudobroscus ground beetle | Pseudobroscus lentus | Species of Concern | Wherever found | |
| Haleakala yellow-faced bee | Hylaeus haleakalae | Species of Concern | Wherever found | |
| Halloween darter | Percina crypta | Under Review | Halloween | |
| Hall's bulrush | Schoenoplectiella hallii | Resolved Taxon | | |
| Hall's bush mallow | Malacothamnus hallii | Not Listed | | |
| Hall's daisy | Erigeron aequifolius | Resolved Taxon | Wherever found | |
| Hall's madia | Madia hallii | Species of Concern | Wherever found | |
| Hall's monardella | Monardella macrantha hallii | Resolved Taxon | Wherever found | |
| Hall's Pocket moss | Fissidens hallii | Status Undefined | | |
| Hall's tarweed | Hemizonia halliana | Resolved Taxon | Wherever found | |
| Hamilton Holospira | Holospira hamiltoni | Resolved Taxon | Wherever found | |
| Hamilton milk-vetch | Astragalus hamiltonii | Resolved Taxon | Wherever found | |
| Hamlin Valley pyrg | Pyrgulopsis hamlinensis | Resolved Taxon | Wherever found | |
| Hammitt's clay-cress | sibaropsis hammittii | Species of Concern | Wherever found | |
| Hanaupah laphamia | Perityle villosa | Species of Concern | Wherever found | |
| Hanna's Vertigo | Vertigo hannai | Resolved Taxon | Wherever found | |
| Hanson's appalachian stonefly | Hansonoperla appalachia | Resolved Taxon | Wherever found | |
| Hao | Rauvolfia sandwicensis sandwicensis | Resolved Taxon | Wherever found | |
| Hapawai | Neritina vespertina | Not Listed | | |
| Hara's cave amphipod | Stygobromus harai | Resolved Taxon | Wherever found | |
| Harbor Porpoise | Phocoena phocoena | Status Undefined | Wherever found | |
| Hardham's bedstraw | Galium hardhamiae | Resolved Taxon | Wherever found | |
| Hardham's evening-primrose | Camissonia hardhamiae | Species of Concern | Wherever found | |
| Hardin crayfish | Orconectes wrighti | Under Review | Wherever found | |
| Hardtoe seepweed | Suaeda nigra | Species of Concern | Wherever found | |
| Hardy Creek barberry | Berberis nervosa mendocinensis | Species of Concern | Wherever found | |
| Hardy pyrg | Pyrgulopsis marcida | Resolved Taxon | Wherever found | |
| Hardy's aegialian scarab | Aegialia hardyi | Resolved Taxon | Wherever found | |
| Hardy's dune beetle | Anomala hardyorum | Resolved Taxon | Wherever found | |
| Harelip sucker | Moxostoma lacerum | Resolved Taxon | Wherever found | |
| Harlequin Darter | Etheostoma histrio | Not Listed | | |
| Harlequin duck | Histrionicus histrionicus | Resolved Taxon | Wherever found | |
| Harney Lake springsnail | Pyrgulopsis hendersoni | Resolved Taxon | Wherever found | |
| Harperella | Ptilimnium nodosum | Endangered | Wherever found | 10-28-1988 |
| Harper's beauty | Harperocallis flava | Endangered | | 11-01-1979 |
| Harper's dodder | Cuscuta harperi | Species of Concern | Wherever found | |
| Harper's fimbristylis | Fimbristylis perpusilla | Under Review | Wherever found | |
| Harper's heartleaf | Hexastylis speciosa | Under Review | Wherever found | |
| Harpy eagle | Harpia harpyja | Endangered | Wherever found | 06-14-1976 |
| Harquahala southern pocket gopher | Thomomys umbrinus subsimilis | Species of Concern | Wherever found | |
| Harrington beardtongue | Penstemon harringtonii | Species of Concern | Wherever found | |
| Harris' mimic swallowtail butterfly | Eurytides lysithous harrisianus | Endangered | Wherever found | 01-09-2025 |
| Harris's Hawk | Parabuteo unicinctus harrisi | Species of Concern | Wherever found | |
| Harris's Sparrow | Zonotrichia querula | Species of Concern | Wherever found | |
| Hartmann's mountain zebra | Equus zebra hartmannae | Threatened | Wherever found | 09-20-1979 |
| Hart's ragwort | Packera hartiana | Species of Concern | Wherever found | |
| Hartweg's golden sunburst | Pseudobahia bahiifolia | Endangered | Wherever found | 02-06-1997 |
| Hartweg's Locust | Robinia hartwigii | Species of Concern | | |
| Hatchie Burrowing crayfish | Fallicambarus hortoni | Not Listed | Wherever found | |
| Hatch's click beetle | Eanus hatchi | Species of Concern | Wherever found | |
| Hat Creek pebblesnail | Fluminicola umbilicatus | Resolved Taxon | Wherever found | |
| Hau kuahiwi | Hibiscadelphus crucibracteatus | Species of Concern | Wherever found | |
| Hau kuahiwi | Hibiscadelphus giffardianus | Endangered | Wherever found | 10-10-1996 |
| Hau kuahiwi | Hibiscadelphus hualalaiensis | Endangered | Wherever found | 10-10-1996 |
| Hau kuahiwi | Hibiscadelphus woodii | Endangered | Wherever found | 10-10-1996 |
| Hawaii akepa | Loxops coccineus | Endangered | Wherever found | 10-13-1970 |
| Hawaii alani long-horned beetle | Plagithmysus vicinus | Species of Concern | Wherever found | |
| Hawai'i 'Amakihi | Chlorodrepanis virens | Species of Concern | Wherever found | |
| Hawaiian aster | Aster sandwicensis | Resolved Taxon | Wherever found | |
| Hawaiian bean leafroller | Omoides monogona | Species of Concern | Wherever found | |
| Hawaiian bluegrass | Poa sandvicensis | Endangered | Wherever found | 05-13-1992 |
| Hawaiian chersodromian dance fly | Chersodromia hawaiiensis | Species of Concern | Wherever found | |
| Hawaiian common gallinule | Gallinula galeata sandvicensis | Endangered | Wherever found | 03-11-1967 |
| Hawaiian coot (alae ke`oke`o) | Fulica alai | Endangered | Wherever found | 10-13-1970 |
| Hawaiian cotton | Gossypium tomentosum | Resolved Taxon | Wherever found | |
| Hawaiian crow | Corvus hawaiiensis | Endangered | Wherever found | 03-11-1967 |
| Hawaiian deinomimesan sphecid wasp | Deinomimesa hawaiiensis | Species of Concern | Wherever found | |
| Hawaiian duck | Anas wyvilliana | Endangered | Wherever found | 03-11-1967 |
| Hawaiian gardenia | Gardenia brighamii | Endangered | Wherever found | 08-21-1985 |
| Hawaiian goose | Branta (=Nesochen) sandvicensis | Threatened | Wherever found | 03-11-1967 |
| Hawaiian hairstreak butterfly | Vaga blackburni | Resolved Taxon | Wherever found | |
| Hawaiian hoary bat | Lasiurus cinereus semotus | Endangered | Wherever found | 10-13-1970 |
| Hawaiian hopseed looper | Scotorythra paratactis | Resolved Taxon | Wherever found | |
| Hawaiian Hypogeal Shrimp | Calliasmata pholidata | Not Listed | | |
| Hawaiian (='lo) Hawk | Buteo solitarius | Recovery | Wherever found | 03-11-1967 |
| Hawaiian long-palp bristletail | Neomachiloides heteropus | Species of Concern | Wherever found | |
| Hawaiian lo`ulu omoides moth | Omoides pritchardii | Species of Concern | Wherever found | |
| Hawaiian monk seal | Monachus schauinslandi | Endangered | Wherever found | 12-23-1976 |
| Hawaiian petrel | Pterodroma sandwichensis | Endangered | Wherever found | 03-11-1967 |
| Hawaiian picture-wing fly | Drosophila aglaia | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila differens | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila digressa | Endangered | Wherever found | 11-29-2013 |
| Hawaiian picture-wing fly | Drosophila hemipeza | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila heteroneura | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila montgomeryi | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila mulli | Threatened | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila musaphilia | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila neoclavisetae | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila obatai | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila ochrobasis | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila sharpi | Endangered | Wherever found | 05-13-2010 |
| Hawaiian picture-wing fly | Drosophila substenoptera | Endangered | Wherever found | 05-09-2006 |
| Hawaiian picture-wing fly | Drosophila tarphytrichia | Endangered | Wherever found | 05-09-2006 |
| Hawaiian proterhinid beetles | Proterhinus spp. (ca 72) | Species of Concern | Wherever found | |
| Hawaiian rhopalid bug | Ithamar hawaiiense | Species of Concern | Wherever found | |
| Hawaiian River Shrimp | Macrobrachium grandimanus | Not Listed | | |
| Hawaiian Short-eared Owl | Asio flammeus sandwichensis | Species of Concern | Wherever found | |
| Hawaiian spider | Doryonychus raptor | Resolved Taxon | Wherever found | |
| Hawaiian stilt | Himantopus mexicanus knudseni | Endangered | Wherever found | 10-13-1970 |
| Hawaiian vetch | Vicia menziesii | Endangered | Wherever found | 05-27-1978 |
| Hawaiian yellow-faced bee | Hylaeus kuakea | Endangered | Wherever found | 10-31-2016 |
| Hawaiian yellow-faced bee | Hylaeus longiceps | Endangered | Wherever found | 10-31-2016 |
| Hawaiian yellow-faced bee | Hylaeus mana | Endangered | Wherever found | 10-31-2016 |
| Hawaii clubbed long-horned beetle | Plagithmysus claviger | Species of Concern | Wherever found | |
| Hawaii creeper | Loxops mana | Endangered | Wherever found | 10-28-1975 |
| Hawaii decorus long-horned beetle | Plagithmysus decorus | Species of Concern | Wherever found | |
| Hawaii elegant long-horned beetle | Plagithmysus elegans | Species of Concern | Wherever found | |
| Hawaii Elepaio | Chasiempis sandwichensis | Species of Concern | Wherever found | |
| Hawaii opuhe long-horned beetle | Plagithmysus sulphurescens | Species of Concern | Wherever found | |
| Hawaii podagricus long-horned beetle | Plagithmysus podagricus | Species of Concern | Wherever found | |
| Hawai`i tree snail | Partulina confusa | Species of Concern | Wherever found | |
| Hawai`i tree snail | Partulina horneri | Species of Concern | Wherever found | |
| Hawai`i tree snail | Partulina physa | Species of Concern | Wherever found | |
| Hawaii uhiuhi long-horned beetle | Plagithmysus mezoneuri | Species of Concern | Wherever found | |
| Hawksbill sea turtle | Eretmochelys imbricata | Endangered | Wherever found | 06-02-1970 |
| Hay's Spring amphipod | Stygobromus hayi | Endangered | Wherever found | 02-05-1982 |
| Hayun Iagu (=(Guam), Tronkon guafi (Rota)) | Serianthes nelsonii | Endangered | Wherever found | 02-18-1987 |
| Headwater catfish | Ictalurus lupus | Resolved Taxon | Wherever found | |
| Headwater chilostigman caddisfly | Chilostigma itascae | Species of Concern | Wherever found | |
| Hearst's ceanothus | Ceanothus hearstiorum | Species of Concern | Wherever found | |
| Hearsts' manzanita | Arctostaphylos hookeri hearstiorum | Species of Concern | Wherever found | |
| Heart-leaved pitcher-sage | Lepechinia cardiophylla | Species of Concern | Wherever found | |
| Heart-leaved plantain | Plantago cordata | Resolved Taxon | Wherever found | |
| Heart-leaved, skullcap | Scutellaria ovata pseudoarguta | Species of Concern | Wherever found | |
| Heartscale | Atriplex cordulata | Species of Concern | Wherever found | |
| Hearty elimia | Elimia jonesi | Resolved Taxon | Wherever found | |
| Heather leaf-flower | Phyllanthus ericoides | Species of Concern | Wherever found | |
| Heau | Exocarpos luteolus | Endangered | Wherever found | 02-25-1994 |
| Heau | Exocarpos menziesii | Endangered | | 10-31-2016 |
| Heavy metromenus ground beetle | Metromenus bardus | Species of Concern | Wherever found | |
| Heavy pigtoe | Pleurobema taitianum | Endangered | Wherever found | 04-07-1987 |
| Hebard's noctuid moth | Erythroecia hebardi | Species of Concern | Wherever found | |
| Heckard's Dwarf Pepper-grass | Lepidium latipes var. heckardii | Status Undefined | Wherever found | |
| Heckner's lewisia | Lewisia cotyledon heckneri | Species of Concern | Wherever found | |
| Heckner's stonecrop | Sedum laxum heckneri | Resolved Taxon | Wherever found | |
| Heermann's Gull | Larus heermanni | Species of Concern | | |
| Heinroth's shearwater | Puffinus heinrothi | Threatened | Wherever found | 01-05-2010 |
| Heliograph Peak Fleabane | Erigeron heliographis | Resolved Taxon | Wherever found | |
| Helios yellow butterfly | Eurema dina helios | Resolved Taxon | Wherever found | |
| Heliotrope milk-vetch | Astragalus montii | Threatened | Wherever found | 11-06-1987 |
| Heliotrope pika | Ochotona princeps moorei | Species of Concern | Wherever found | |
| Hell Creek Cave crayfish | Cambarus zophonastes | Endangered | Wherever found | 04-07-1987 |
| Heller Cave springtail | Typhlogastrura helleri | Under Review | Wherever found | |
| Heller's bird's-foot trefoil | Lotus unifoliolatus var. helleri | Species of Concern | Wherever found | |
| Heller's blazingstar | Liatris helleri | Threatened | Wherever found | 11-19-1987 |
| Helma's net-spinning caddisfly | Cheumatopsyche helma | Species of Concern | Wherever found | |
| Helmeted honeyeater | Lichenostomus melanops cassidix (=Meliphaga c.) | Endangered | Wherever found | 12-02-1970 |
| Helmeted hornbill | Buceros (=Rhinoplax) vigil | Endangered | Wherever found | 06-14-1976 |
| Helmeted woodpecker | Celeus galeatus | Candidate | Wherever found | |
| Helmet rocksnail | Lithasia duttoniana | Not Listed | Wherever found | |
| Helotes mold beetle | Batrisodes venyivi | Endangered | Wherever found | 12-26-2000 |
| Hemlock, Mexican parsley | Conioselinum mexicanum | Species of Concern | Wherever found | |
| Henderson's bentgrass | Agrostis hendersonii | Species of Concern | Wherever found | |
| Henderson's checkermallow | Sidalcea hendersonii | Resolved Taxon | Wherever found | |
| Henderson's horkelia | Horkelia hendersonii | Resolved Taxon | Wherever found | |
| Henne's eucosman moth | Eucosma hennei | Species of Concern | Wherever found | |
| Henry's Common Nighthawk | Chordeiles minor henryi | Species of Concern | | |
| Henry's spider-lily | Hymenocallis henryae | Under Review | Wherever found | |
| Henslow's Sparrow | Centronyx henslowii | Resolved Taxon | Wherever found | |
| Herald Petrel | Pterodroma arminjoniana | Species of Concern | Wherever found | |
| Hermes copper butterfly | Lycaena hermes | Threatened | Wherever found | 01-20-2022 |
| Hermit Warbler | Setophaga occidentalis | Species of Concern | | |
| Herring Gull | Larus argentatus | Species of Concern | Wherever found | |
| Hershler groundwater sebid | Seborgia hershleri | Resolved Taxon | Wherever found | |
| Hessel's hairstreak butterfly | Mitoura hesseli | Resolved Taxon | Wherever found | |
| Hess's fleabane | Erigeron hessii | Resolved Taxon | Wherever found | |
| Hester's cory cactus | Escobaria hesteri | Species of Concern | Wherever found | |
| Hetch Hetchy monkey-flower | Mimulus filicaulis | Species of Concern | Wherever found | |
| Hexagenia Mayfly | Hexagenia limbata | Not Listed | | |
| Hicaquillo | Dendropemon sintenisii | Species of Concern | Wherever found | |
| Hickman's onion | Allium hickmanii | Species of Concern | Wherever found | |
| Hickman's potentilla | Potentilla hickmanii | Endangered | Wherever found | 08-12-1998 |
| Hickman's sidalcea | Sidalcea hickmanii hickmanii | Resolved Taxon | Wherever found | |
| Hickorynut | Obovaria olivaria | Not Listed | | |
| Hickory Nut Gorge green salamander | Aneides caryaensis | Under Review | | |
| Hickory Shad | Alosa mediocris | Not Listed | | |
| Hidden bluecurls | Trichostema latens | Status Undefined | | |
| Hidden eopenthes click beetle | Eopenthes celatus | Species of Concern | Wherever found | |
| Hidden Forest Uinta chipmunk | Eutamias umbrinus nevadensis | Species of Concern | Wherever found | |
| Hidden Lake bluecurls | Trichostema austromontanum ssp. compactum | Recovery | Wherever found | 10-14-1998 |
| Hidden pebblesnail | Somatogyrus decipiens | Species of Concern | Wherever found | |
| Hierro giant lizard | Gallotia simonyi simonyi | Endangered | Wherever found | 02-29-1984 |
| Higgin's barberry | Berberis higginsiae | Resolved Taxon | Wherever found | |
| Higgins biscuitroot | Cymopterus acaulis higginsii | Species of Concern | Wherever found | |
| Higgins eye (pearlymussel) | Lampsilis higginsii | Endangered | Wherever found | 06-14-1976 |
| Highfin Carpsucker | Carpiodes velifer | Not Listed | | |
| Highlands moss | Schlotheimia lancifolia | Species of Concern | Wherever found | |
| Highlands scrub hypericum | Hypericum cumulicola | Endangered | | 01-21-1987 |
| Highlands tiger beetle | Cicindelidia highlandensis | Resolved Taxon | Wherever found | |
| High Rock Springs tui chub | Siphateles bicolor ssp. | Resolved Taxon | High Rock | |
| Highscale shiner | Notropis hypsilepis | Species of Concern | Wherever found | |
| High-spired elimia | Elimia hartmaniana | Resolved Taxon | Wherever found | |
| Higo Chumbo | Harrisia portoricensis | Threatened | Wherever found | 08-08-1990 |
| Higuero de sierra | Crescentia portoricensis | Endangered | Wherever found | 12-04-1987 |
| Hihiwai | Neritina granosa | Not Listed | | |
| Hiko White River springfish | Crenichthys baileyi grandis | Endangered | Wherever found | 09-27-1985 |
| Hilaris yellow-faced bee | Hylaeus hilaris | Endangered | Wherever found | 10-31-2016 |
| Hillebrand's reedgrass | Calamagrostis hillebrandii | Endangered | Wherever found | 06-27-2013 |
| Hill's Horseshoe Bat | Rhinoiophus hilli | Under Review | Wherever found | |
| Hill's pondweed | Potamogeton hillii | Resolved Taxon | Wherever found | |
| Hilo hypenan noctuid moth | Hypena newelli | Resolved Taxon | Wherever found | |
| Hilo ischaemum | Ischaemum byrone | Endangered | Wherever found | 03-04-1994 |
| Hilton Head white-tailed deer | Odocoileus virginianus hiltonensis | Species of Concern | Wherever found | |
| Hinckley oak | Quercus hinckleyi | Threatened | Wherever found | 08-26-1988 |
| Hinckley's bricklebush | Brickellia brachyphylla montanus | Species of Concern | Wherever found | |
| Hinckley's columbine | Aquilegia chrysantha hinckleyana | Species of Concern | Wherever found | |
| Hinckley's jacob's ladder | Polemonium pauciflorum hinckleyi | Species of Concern | Wherever found | |
| Hine's emerald dragonfly | Somatochlora hineana | Endangered | Wherever found | 01-26-1995 |
| Hirst Brothers' Panic grass | Dichanthelium (=Panicum) hirstii | Resolved Taxon | Wherever found | |
| Hirsute sierra sideband | Monadenia mormonum hirsuta | Species of Concern | Wherever found | |
| Hirsute yellow-faced bee | Hylaeus hirsutulus | Species of Concern | Wherever found | |
| Hispid birds-beak | Cordylanthus mollis hispidus | Species of Concern | Wherever found | |
| Hispid hare | Caprolagus hispidus | Endangered | Wherever found | 06-14-1976 |
| Hitchcock's blue-eyed grass | Sisyrinchium hitchcockii | Species of Concern | Wherever found | |
| Hiwassee headwater crayfish | Cambarus hiwasseensis | Species of Concern | Wherever found | |
| hoary bat | Lasiurus cinereus | Status Undefined | Wherever found | |
| Hoawa | Pittosporum halophilum | Endangered | Wherever found | 06-27-2013 |
| Hoawa | Pittosporum hawaiiense | Endangered | Wherever found | 11-29-2013 |
| Ho`awa | Pittosporum napaliense | Endangered | Wherever found | 05-13-2010 |
| Hobb's cave amphipod | Crangonyx hobbsi | Under Review | Wherever found | |
| Hoffmann's buckwheat | Eriogonum hoffmannii hoffmannii | Resolved Taxon | Wherever found | |
| Hoffmann's cactus | Opuntia bigelovii hoffmannii | Resolved Taxon | Wherever found | |
| Hoffmann's cryptantha | Cryptantha hoffmannii | Resolved Taxon | Wherever found | |
| Hoffmann's rock-cress | Arabis hoffmannii | Endangered | Wherever found | 07-31-1997 |
| Hoffmann's slender-flowered gilia | Gilia tenuiflora ssp. hoffmannii | Endangered | Wherever found | 07-31-1997 |
| Hoffman's sanicle | Sanicula hoffmannii | Resolved Taxon | Wherever found | |
| Hohiu | Dryopteris glabra var. pusilla | Endangered | Wherever found | 10-31-2016 |
| Hoja menuda | Psidium sintenisii | Species of Concern | Wherever found | |
| Hoko vertigo | Vertigo sp | Not Listed | Wherever found | |
| Holei | Ochrosia haleakalae | Endangered | Wherever found | 10-31-2016 |
| Holei | Ochrosia kilaueaensis | Endangered | Wherever found | 03-04-1994 |
| Hole-In-The-Rock prairie-clover | Dalea flavescens epica | Species of Concern | Wherever found | |
| Holiday darter | Etheostoma brevirostrum | Status Undefined | Wherever found | |
| Hollisteria | Hollisteria lanata | Species of Concern | Wherever found | |
| Holly-leaved tetracoccus | Tetracoccus ilicifolius | Resolved Taxon | Wherever found | |
| Holmgren milk-vetch | Astragalus holmgreniorum | Endangered | Wherever found | 09-28-2001 |
| Holmgren's buckwheat | Eriogonum holmgrenii | Species of Concern | Wherever found | |
| Holmgren's lupine | Lupinus holmgrenianus | Resolved Taxon | Wherever found | |
| Holsinger's Cave Beetle | Pseudanophthalmus holsingeri | Resolved Taxon | Wherever found | |
| Holsinger's groundwater amphipod | Stygobromus holsingeri | Resolved Taxon | Wherever found | |
| Holsinger's groundwater planarian | Sphalloplana holsingeri | Resolved Taxon | Wherever found | |
| Holy Ghost ipomopsis | Ipomopsis sancti-spiritus | Endangered | Wherever found | 03-23-1994 |
| Homerus swallowtail butterfly | Papilio homerus | Endangered | Wherever found | 01-14-1993 |
| Homossassa shrew | Sorex longirostris eionis | Resolved Taxon | Wherever found | |
| Hom's micro-blind harvestman | Microcina homi | Species of Concern | Wherever found | |
| Honduran emerald hummingbird | Amazilia luciae | Endangered | Wherever found | 08-28-2015 |
| Honohono | Haplostachys haplostachya | Endangered | Wherever found | 11-29-1979 |
| Honolulu melicope | Melicope hosakae | Resolved Taxon | Wherever found | |
| Hood ancylid | Ferrissia mcneili | Species of Concern | Wherever found | |
| Hooded Crane | Grus monacha | Endangered | Wherever found | 12-02-1970 |
| Hooded Oriole | Icterus cucullatus | Species of Concern | Wherever found | |
| Hook-billed hermit (hummingbird) | Ramphodon (=Glaucis) dohrnii | Endangered | Wherever found | 06-14-1976 |
| Hooker's manzanita | arctostaphylos hookeri ssp. hookeri | Species of Concern | Wherever found | |
| Hoover's button-celery | Eryngium aristulatum hooveri | Species of Concern | Wherever found | |
| Hoover's coyot bush | Baccharis plummerae glabrata | Resolved Taxon | Wherever found | |
| Hoover's desert-parsley | Lomatium tuberosum | Species of Concern | Wherever found | |
| Hoover's rosinweed | Calycadenia hooveri | Species of Concern | Wherever found | |
| Hoover's spurge | Chamaesyce hooveri | Threatened | Wherever found | 03-26-1997 |
| Hoover's tauschia | Tauschia hooveri | Species of Concern | Wherever found | |
| Hoover's woolly-star | Eriastrum hooveri | Recovery | | 07-19-1990 |
| Hopping's blister beetle | Lytta hoppingi | Species of Concern | Wherever found | |
| Horned Grebe | Podiceps auritus | Status Undefined | Wherever found | |
| Horned guan | Oreophasis derbianus | Endangered | Wherever found | 06-02-1970 |
| Hornwort | Megaceros aenigmaticus | Status Undefined | | |
| Hornyhead Chub | Nocomis biguttatus | Not Listed | | |
| Horse | Equus caballus | Resolved Taxon | Wherever found | |
| Horseshoe Canyon Talussnail | Sonorella binneyi | Resolved Taxon | Wherever found | |
| Horseshoe Canyon Woodlandsnail | Ashmunella lenticula | Resolved Taxon | Wherever found | |
| Horseshoe Crab | Limulus polyphemus | Not Listed | | |
| Horseshoe liptooth | Polygyra hippocrepis | Species of Concern | Wherever found | |
| Horseshoe Liptooth | Daedalochila hippocrepis | Resolved Taxon | Wherever found | |
| Horseshoe milk-vetch | Astragalus equisolensis | Resolved Taxon | Wherever found | |
| Horseshoe snail | Micrarionta intercisa | Resolved Taxon | Wherever found | |
| Hoskett Meadows lupine | Lupinus culbertsonii culbertsonii | Resolved Taxon | Wherever found | |
| Hospital Canyon larkspur | Delphinium californicum interius | Species of Concern | Wherever found | |
| Hostile yellow-faced bee | Hylaeus hostilis | Species of Concern | Wherever found | |
| Hot Creek Valley tui chub | Siphateles bicolor ssp. 5 | Species of Concern | Wherever found | |
| Hot dots | Arthonia kermesina | Species of Concern | | |
| Hot Springs cotton rat | Sigmodon fulviventer goldmani | Species of Concern | Wherever found | |
| Hot springs fimbristylis | Fimbristylis thermalis | Resolved Taxon | Wherever found | |
| Houghton's goldenrod | Solidago houghtonii | Threatened | Wherever found | 07-18-1988 |
| Houston meadowrue | Thalictrum texanum | Species of Concern | Wherever found | |
| Houston tansyaster | Rayjacksonia aurea | Species of Concern | Wherever found | |
| Houston toad | Bufo houstonensis | Endangered | Wherever found | 10-13-1970 |
| Howarth's cave cricket | Caconemobius howarthi | Species of Concern | Wherever found | |
| Howell phacelia | Phacelia howelliana | Resolved Taxon | Wherever found | |
| Howell's alkali grass | Puccinellia howellii | Species of Concern | Wherever found | |
| Howell's bentgrass | Agrostis howellii | Species of Concern | Wherever found | |
| Howell's fawn-lily | Erythronium howellii | Resolved Taxon | Wherever found | |
| Howell's fleabane | Erigeron howellii | Species of Concern | Wherever found | |
| Howell's gumplant | Grindelia howellii | Species of Concern | Wherever found | |
| Howell's jewelflower | Streptanthus howellii | Resolved Taxon | Wherever found | |
| Howell's lewisia | Lewisia cotyledon howellii | Species of Concern | Wherever found | |
| Howell's lomatium | Lomatium howellii | Resolved Taxon | Wherever found | |
| Howell's lousewort | Pedicularis howellii | Resolved Taxon | Wherever found | |
| Howell's mariposa lily | Calochortus howellii | Species of Concern | Wherever found | |
| Howell's montia | Montia howellii | Species of Concern | Wherever found | |
| Howell's onion | Allium pleianthum | Resolved Taxon | Wherever found | |
| Howell's sandwort | Minuartia howellii | Resolved Taxon | Wherever found | |
| Howell''s spectacular thelypody | Thelypodium howellii ssp. spectabilis | Threatened | Wherever found | 05-26-1999 |
| Howell's spineflower | Chorizanthe howellii | Endangered | Wherever found | 06-22-1992 |
| Howell's tauschia | Tauschia howellii | Species of Concern | Wherever found | |
| Howe's hedgehog cactus | Echinocereus engelmannii howei | Species of Concern | Wherever found | |
| Huachuca groundsel | Senecio huachucanus | Species of Concern | Wherever found | |
| Huachuca milk-vetch | Astragalus hypoxylus | Resolved Taxon | | |
| Huachuca springsnail | Pyrgulopsis thompsoni | Resolved Taxon | Wherever found | |
| Huachuca water-umbel | Lilaeopsis schaffneriana var. recurva | Endangered | Wherever found | 01-06-1997 |
| Huachuca Woodlandsnail | Ashmunella levettei | Under Review | Wherever found | |
| Hualapai Mexican vole | Microtus mexicanus hualpaiensis | Original Data in Error - Not a listable entity | Wherever found | 10-01-1987 |
| Hualapai southern pocket gopher | Thomomys umbrinus hualpaiensis | Species of Concern | Wherever found | |
| Hubbard's cave beetle | Pseudanophthalmus hubbardi | Resolved Taxon | Wherever found | |
| Hubbs pyrg | Pyrgulopsis hubbsi | Resolved Taxon | Wherever found | |
| Huber's Pepperwort | Lepidium huberi | Resolved Taxon | Wherever found | |
| Hubricht's cave beetle | Pseudanophthalmus hubrichti | Resolved Taxon | Wherever found | |
| Hubricht's vertigo | Vertigo hubrichti | Species of Concern | Wherever found | |
| Hudson Bay Dunlin | Calidris alpina hudsonia | Species of Concern | | |
| Hudson clubtail dragonfly | Gomphus adelphus | Resolved Taxon | Wherever found | |
| Hudsonian Godwit | Limosa haemastica | Species of Concern | Wherever found | |
| Hueco Cavesnail | Phreatodrobia conica | Resolved Taxon | Wherever found | |
| hueco mountains talus snail | sonorella huecoensis | Resolved Taxon | Wherever found | |
| Hueco rock-daisy | Perityle huecoensis | Resolved Taxon | Wherever found | |
| Hulan yellow-faced bee | Hylaeus hula | Species of Concern | Wherever found | |
| Hulumoa | Korthalsella degeneri | Endangered | Wherever found | 10-18-2012 |
| Humboldt Bay gumplant | Grindelia stricta blakei | Species of Concern | Wherever found | |
| Humboldt Bay owl's clover | Castilleja ambigua humboldtiensis | Species of Concern | Wherever found | |
| Humboldt ground beetle | Scaphinotus longiceps | Species of Concern | Wherever found | |
| Humboldt lily | Lilium humboldtii ocellatum | Species of Concern | Wherever found | |
| Humboldt milk-vetch | Astragalus agnicidus | Species of Concern | Wherever found | |
| Humboldt penguin | Spheniscus humboldti | Threatened | Wherever found | 09-02-2010 |
| Humpback chub | Gila cypha | Threatened | Wherever found | 03-11-1967 |
| Humpback whale | Megaptera novaeangliae | Endangered | Arabian Sea DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Endangered | Cape Verde Island/Northwest Africa | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Endangered | Central America DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Endangered | Western North Pacific | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Brazil DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | East Australia DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Gabon/Southwest Africa DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Hawaii DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Oceania DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Southeast Africa/Madagascar DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | Southeastern Pacific DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | West Australia DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Recovery | West Indies DPS | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Resolved Taxon | Wherever found | 06-02-1970 |
| Humpback whale | Megaptera novaeangliae | Threatened | Mexico DPS | 06-02-1970 |
| Humpback Whitefish | Coregonus pidschian | Not Listed | | |
| Humped tree snail | Partula gibba | Endangered | Wherever found | 11-02-2015 |
| Hungerford's crawling water Beetle | Brychius hungerfordi | Endangered | Wherever found | 03-07-1994 |
| Hunting Island white-tailed deer | Odocoileus virginianus venatoria | Species of Concern | Wherever found | |
| Hurd's metapogon robberfly | Metapogon hurdi | Species of Concern | Wherever found | |
| Hutchinson's delphinium | Delphinium hutchinsonae | Species of Concern | Wherever found | |
| Hutton tui chub | Gila bicolor ssp. | Threatened | Wherever found | 03-28-1985 |
| Hyacinth macaw | Anodorhynchus hyacinthinus | Threatened | Wherever found | 09-12-2018 |
| Hydaspe fritillary butterfly | Speyeria hydaspe conquista | Resolved Taxon | Wherever found | |
| Iao Valley nesosydne planthopper | Nesosydne acuta | Species of Concern | Wherever found | |
| Ibadan malimbe | Malimbus ibadanensis | Endangered | Wherever found | 01-12-1995 |
| Ibiza wall lizard | Podarcis pityusensis | Threatened | Wherever found | 02-29-1984 |
| Icebox Cave beetle | Pseudanophthalmus frigidus | Resolved Taxon | Wherever found | |
| Ice grass | Phippsia algida | Resolved Taxon | Wherever found | |
| Ichetucknee siltsnail | Floridobia mica | Resolved Taxon | Wherever found | |
| Idaho banded mountainsnail | Oreohelix idahoensis idahoensis | Species of Concern | Wherever found | |
| Idaho dunes tiger beetle | Cicindela arenicola | Species of Concern | Wherever found | |
| Idaho penstemon | Penstemon idahoensis | Species of Concern | Wherever found | |
| Idaho pointheaded grasshopper | Acrolophitus pulchellus | Species of Concern | Wherever found | |
| Idaho snowfly | Capnia zukeli | Resolved Taxon | Wherever found | |
| Idaho springsnail | Pyrgulopsis idahoensis | Original Data in Error - Taxonomic Revision | Wherever found | 12-14-1992 |
| Idria buckwheat | Eriogonum vestitum | Resolved Taxon | Wherever found | |
| Ihi | Portulaca villosa | Endangered | Wherever found | 10-31-2016 |
| Ihi`ihi | Marsilea villosa | Endangered | Wherever found | 06-22-1992 |
| `I`iwi | Drepanis coccinea | Threatened | Wherever found | 10-20-2017 |
| Ikan temoleh (minnow) | Probarbus jullieni | Endangered | Wherever found | 06-14-1976 |
| `Ilihia | Cyrtandra begoniifolia | Resolved Taxon | Wherever found | |
| Illinois cave amphipod | Gammarus acherondytes | Endangered | Wherever found | 09-03-1998 |
| Illinois cave beetle | Pseudanophthalmus illinoisensis | Species of Concern | Wherever found | |
| Illinois chorus frog | Pseudacris illinoensis | Resolved Taxon | Wherever found | |
| Illinois mud turtle | Kinosternon flavescens spooneri | Resolved Taxon | Wherever found | |
| Imperial parrot | Amazona imperialis | Endangered | Wherever found | 06-02-1970 |
| Imperial pheasant | Lophura imperialis | Endangered | Wherever found | 06-02-1970 |
| Imperial woodpecker | Campephilus imperialis | Endangered | Wherever found | 06-02-1970 |
| Inagua Island turtle | Trachemys stejnegeri malonei | Endangered | Wherever found | 09-30-1991 |
| Incised groovebur | Agrimonia incisa | Species of Concern | Wherever found | |
| Inconnu | Stenodus leucichthys | Not Listed | | |
| Independence Valley speckled dace | Rhinichthys osculus lethoporus | Endangered | Wherever found | 10-10-1989 |
| Independence Valley tui chub | Siphateles bicolor isolata | Species of Concern | Wherever found | |
| Indiana bat | Myotis sodalis | Endangered | Wherever found | 03-11-1967 |
| Indiana crayfish | Orconectes indianensis | Species of Concern | Wherever found | |
| Indiana river snail | Goniobasis semicarinata indianensis | Resolved Taxon | Wherever found | |
| Indian (=Bengal) monitor | Varanus bengalensis | Endangered | Wherever found | 06-14-1976 |
| Indian Creek mushroom | Gloeocantharellus purpurascens | Resolved Taxon | Wherever found | |
| Indian flap-shelled turtle | Lissemys punctata punctata | Original Data in Error - Erroneous Data | Wherever found | 06-14-1976 |
| Indian Grave Point (=Soothsayer) cave beetle | Pseudanophthalmus tiresias | Resolved Taxon | Wherever found | |
| Indian Knob mountainbalm | Eriodictyon altissimum | Endangered | Wherever found | 12-15-1994 |
| Indian pangolin | Manis crassicaudata | Under Review | Wherever found | |
| Indian pipe | Monotropa uniflora | Species of Concern | Wherever found | |
| Indian python | Python molurus molurus | Endangered | Wherever found | 06-14-1976 |
| Indian sawback turtle | Kachuga tecta tecta | Endangered | Wherever found | 06-14-1976 |
| Indian softshell turtle | Trionyx gangeticus | Endangered | Wherever found | 06-14-1976 |
| Indian Valley brodiaea | Brodiaea coronaria rosea | Species of Concern | Wherever found | |
| Indian Valley sedge | Carex parryana | Resolved Taxon | Wherever found | |
| Indian Valley spineflower | Aristocapsa insignis | Resolved Taxon | Wherever found | |
| Indigo macaw | Anodorhynchus leari | Endangered | Wherever found | 06-14-1976 |
| Indochina hog deer | Axis porcinus annamiticus | Endangered | Wherever found | 06-14-1976 |
| Indri lemur | Indri indri | Endangered | Wherever found | 06-02-1970 |
| Inflated floater | Pyganodon gibbosa | Not Listed | Wherever found | |
| Inflated heelsplitter | Potamilus inflatus | Threatened | Wherever found | 09-28-1990 |
| Inflated spike | Elliptio purpurella | Status Undefined | Wherever found | |
| Inquirer Cave beetle | Pseudanophthalmus inquisitor | Resolved Taxon | Wherever found | |
| Insignis yellow-faced bee | Hylaeus insignis | Species of Concern | Wherever found | |
| Insular hispid Cotton rat | Sigmodon hispidus insulicola | Under Review | Wherever found | |
| Insular long-tongued bat | Monophylus plethodon frater | Resolved Taxon | Wherever found | |
| Interior redband trout | Oncorhynchus mykiss gibbsi | Species of Concern | Wherever found | |
| Intermediate groundsel | Senecio dimorphophyllus intermedius | Resolved Taxon | Wherever found | |
| Interrupted (=Georgia) Rocksnail | Leptoxis foremani | Endangered | Wherever found | 12-02-2010 |
| Inyo California towhee | Melozone crissalis eremophilus | Threatened | Wherever found | 08-03-1987 |
| Inyo hulsea | Hulsea vestita inyoensis | Resolved Taxon | Wherever found | |
| Inyo lomatium | Lomatium foeniculaceum inyoense | Resolved Taxon | Wherever found | |
| Inyo lupine | Lupinus inyoensis | Resolved Taxon | Wherever found | |
| Inyo mariposa lily | Calochortus excavatus | Species of Concern | Wherever found | |
| Inyo Mountains slender salamander | Batrachoseps campi | Status Undefined | Wherever found | |
| Inyo penstemon | Penstemon papillatus | Resolved Taxon | Wherever found | |
| Inyo rock daisy | Perityle inyoensis | Under Review | Wherever found | |
| Ione (incl. Irish Hill) buckwheat | Eriogonum apricum (incl. var. prostratum) | Endangered | Wherever found | 05-26-1999 |
| Ione manzanita | Arctostaphylos myrtifolia | Threatened | Wherever found | 05-26-1999 |
| Iowa amphipod | Stygobromus iowae | Resolved Taxon | Wherever found | |
| Iowa Darter | Etheostoma exile | Not Listed | | |
| Iowa Pleistocene snail | Discus macclintocki | Endangered | Wherever found | 08-02-1978 |
| Iowa Pleistocene Succineid | Succinea sp. | Species of Concern | IA | |
| Iowa Pleistocene Vertigo | Vertigo sp. | Species of Concern | Wherever found | |
| Iowa skipper | Atrytone arogos iowa | Not Listed | | |
| Ioxanthan looper | Kauaiina ioxantha | Species of Concern | Wherever found | |
| Iriomote cat | Prionailurus (=Felis) bengalensis iriomotensis | Endangered | Wherever found | 07-27-1979 |
| Irion County wild-buckwheat | Eriogonum nealleyi | Resolved Taxon | Wherever found | |
| Ironcolor Shiner | Notropis chalybaeus | Not Listed | | |
| Iron Creek woodlandsnail | Ashmunella mendax | Resolved Taxon | Wherever found | |
| Irons Fork Burrowing crayfish | Procambarus reimeri | Status Undefined | Wherever found | |
| Isely milk-vetch | Astragalus iselyi | Resolved Taxon | Wherever found | |
| Island alumroot | Heuchera maxima | Resolved Taxon | Wherever found | |
| Island Barberry | Berberis pinnata ssp. insularis | Endangered | Wherever found | 07-31-1997 |
| Island bedstraw | Galium buxifolium | Recovery | Wherever found | 07-31-1997 |
| Island fox | Urocyon littoralis | Status Undefined | Wherever found | |
| Island glass lizard | Ophisaurus compressus | Species of Concern | Wherever found | |
| Island green dudleya | dudleya virens ssp. insularis | Species of Concern | Wherever found | |
| Island Grouper | Mycteroperca fusca | Threatened | | |
| Island hazardia | Hazardia cana | Species of Concern | Wherever found | |
| Island jepsonia | Jepsonia malvifolia | Species of Concern | Wherever found | |
| Island loggerhead shrike | Lanius ludovicianus ssp. anthonyi | Resolved Taxon | Wherever found | |
| Island malacothrix | Malacothrix squalida | Endangered | Wherever found | 07-31-1997 |
| Island marble Butterfly | Euchloe ausonides insulanus | Endangered | Wherever found | 06-04-2020 |
| Island morning-glory | Calystegia macrostegia amplissima | Species of Concern | Wherever found | |
| Island night lizard | Xantusia riversiana | Recovery | Wherever found | 09-12-1977 |
| Island oak | Quercus tomentella | Resolved Taxon | Wherever found | |
| Island phacelia | Phacelia insularis ssp. insularis | Endangered | Wherever found | 07-31-1997 |
| Island poppy | Eschscholzia ramosa | Resolved Taxon | Wherever found | |
| Island rush-rose | Helianthemum greenei | Threatened | Wherever found | 07-31-1997 |
| Island Scrub-Jay | Aphelocoma insularis | Species of Concern | Wherever found | |
| Island snapdragon | Gambelia speciosa | Species of Concern | Wherever found | |
| Island tree mallow | Lavatera assurgentiflora | Species of Concern | Wherever found | |
| Island tree poppy | Dendromecon rigida rhamnoides | Species of Concern | Wherever found | |
| Island wallflower | Erysimum insulare insulare | Species of Concern | Wherever found | |
| Israel painted frog | Discoglossus nigriventer | Endangered | Wherever found | 06-02-1970 |
| Italian grey Partridge | Perdix perdix italica | Resolved Taxon | Wherever found | |
| Ivory-billed woodpecker | Campephilus principalis | Endangered | Wherever found | 03-11-1967 |
| Ivory Gull | Pagophila eburnea | Species of Concern | | |
| Ivory Ornamental Tarantula | Poecilotheria subfusca | Endangered | Wherever found | 08-30-2018 |
| Ivory-spined agave | Agave utahensis eborispina | Resolved Taxon | Wherever found | |
| Jacalitos Jerusalem cricket | Stenopelmatus nigrocapitatus | Resolved Taxon | Wherever found | |
| Jacalitos shield-backed katydid | Ateloplus joaquin | Resolved Taxon | Wherever found | |
| Jackie's Bluet | Hedyotis pooleana | Resolved Taxon | Wherever found | |
| Jackson Lake snail | Helisoma jacksonense | Species of Concern | Wherever found | |
| Jackson Lake springsnail | Pyrgulopsis robusta | Resolved Taxon | Wherever found | |
| Jackson Prairie crayfish | Procambarus barbiger | Under Review | Wherever found | |
| Jacumba little pocket mouse | Perognathus longimembris internationalis | Species of Concern | Wherever found | |
| Jacumba milk-vetch | Astragalus douglasii perstrictus | Species of Concern | Wherever found | |
| Jaeger's bush milk-vetch | Astragalus pachypus jaegeri | Species of Concern | Wherever found | |
| Jaeger's caulostramina | Caulostramina jaegeri | Species of Concern | Wherever found | |
| Jaeger's thelypody | Thelypodium repandum | Species of Concern | Wherever found | |
| Jaguar | Panthera onca | Endangered | Wherever found | 03-28-1972 |
| Jamaican boa | Epicrates subflavus | Endangered | Wherever found | 06-02-1970 |
| Jamaican Greater Funnel-Eared Bat | Natalus jamaicensis | Under Review | Wherever found | |
| Jamaican iguana | Cyclura collei | Endangered | Wherever found | 06-22-1983 |
| Jamaican kite swallowtail butterfly | Eurytides marcellinus | Candidate | Wherever found | |
| James spinymussel | Parvaspina collina | Endangered | Wherever found | 07-22-1988 |
| Jan's catchfly | Silene nachlingerae | Species of Concern | Wherever found | |
| Japanese Crane | Grus japonensis | Endangered | Wherever found | 06-02-1970 |
| Japanese crested ibis | Nipponia nippon | Endangered | Wherever found | 06-02-1970 |
| Japanese giant salamander | Andrias japonicus (=davidianus j.) | Endangered | Wherever found | 06-14-1976 |
| Japanese macaque | Macaca fuscata | Threatened | Wherever found | 10-19-1976 |
| Jared's peppergrass | Lepidium jaredii jaredii | Species of Concern | Wherever found | |
| Javan rhinoceros | Rhinoceros sondaicus | Endangered | Sikkim, Thailand, Malaysia, Indonesia, Indochina, Burma, Bangladesh | 06-02-1970 |
| Jaynes Canyon buckwheat | Eriogonum diclinum | Resolved Taxon | Wherever found | |
| Jeff Davis Parish indian paintbrush | Castilleja coccinea | Resolved Taxon | Wherever found | |
| Jefferson County crayfish | Fallicambarus gilpini | Not Listed | Wherever found | |
| Jemez Mountains Amphipod | Stygobromus jemezensis | Resolved Taxon | Wherever found | |
| Jemez Mountains salamander | Plethodon neomexicanus | Endangered | Wherever found | 10-10-2013 |
| Jemez Woodlandsnail | Ashmunella ashmuni | Resolved Taxon | Wherever found | |
| Jennifer�s monardella | Monardella stoneana | Resolved Taxon | Wherever found | |
| Jenny Creek sucker | Catostomus rimiculus ssp. | Species of Concern | Wherever found | |
| Jentink's duiker | Cephalophus jentinki | Endangered | Wherever found | 07-27-1979 |
| Jepson's onion | Allium jepsonii | Species of Concern | Wherever found | |
| Jerdon's courser | Rhinoptilus bitorquatus | Endangered | Wherever found | 09-12-2011 |
| Jessica's aster | Symphyotrichum jessicae | Species of Concern | Wherever found | |
| Jesup's milk-vetch | Astragalus robbinsii var. jesupii | Endangered | Wherever found | 06-05-1987 |
| Jicotea | Pseudemys stejnegeri | Species of Concern | Wherever found | |
| Jobé bluecurls | Trichostema hobe | Status Undefined | | |
| Johnny Darter | Etheostoma nigrum | Not Listed | | |
| Johnson's seagrass | Halophila johnsonii | Original Data in Error - Not a listable entity | Wherever found | 09-14-1998 |
| Johnston catseye | Cryptantha johnstonii | Resolved Taxon | Wherever found | |
| Johnston's buckwheat | Eriogonum microthecum johnstonii | Species of Concern | Wherever found | |
| Johnston's frankenia | Frankenia johnstonii | Recovery | Wherever found | 08-07-1984 |
| Johnston's rock-cress | Arabis johnstonii | Resolved Taxon | Wherever found | |
| Jointed buckwheat | Eriogonum intrafractum | Species of Concern | Wherever found | |
| Jollyville Plateau Salamander | Eurycea tonkawae | Threatened | Wherever found | 09-19-2013 |
| Jones catseye | Cryptantha jonesiana | Resolved Taxon | Wherever found | |
| Jones' columbine | Aquilegia jonesii | Resolved Taxon | Wherever found | |
| Jones Cycladenia | Cycladenia humilis var. jonesii | Threatened | Wherever found | 05-05-1986 |
| Jones' dogbane | Apocynum X floribundum | Resolved Taxon | Wherever found | |
| Jones' globe-mallow | Sphaeralcea caespitosa | Species of Concern | Wherever found | |
| Jones golden aster | Heterotheca jonesii | Resolved Taxon | Wherever found | |
| Jones layia | Layia jonesii | Species of Concern | Wherever found | |
| Jones' oxytrope | Oxytropis oreophila var. jonesii | Resolved Taxon | Wherever found | |
| Jones' selenia | Selenia jonesii | Resolved Taxon | Wherever found | |
| Josselyn's sedge | Carex josselynii | Resolved Taxon | Wherever found | |
| Jugorum megalagrion damselfly | Megalagrion jugorum | Resolved Taxon | Wherever found | |
| July gold | Dedeckera eurekensis | Species of Concern | Wherever found | |
| Junaluska salamander | Eurycea junaluska | Resolved Taxon | Wherever found | |
| June sucker | Chasmistes liorus | Threatened | Wherever found | 03-31-1986 |
| Jung's micro-blind harvestman | Microcina jungi | Under Review | Wherever found | |
| Junin grebe | Podiceps taczanowskii | Endangered | Wherever found | 07-24-2012 |
| Junin rail | Laterallus tuerosi | Endangered | Wherever found | 07-24-2012 |
| Juniper Titmouse | Baeolophus ridgwayi | Species of Concern | Wherever found | |
| Kachina daisy | Erigeron kachinensis | Species of Concern | Wherever found | |
| Kaempfer's tody-tyrant | Hemitriccus kaempferi | Endangered | Wherever found | 01-27-2011 |
| Kagu | Rhynochetos jubatus | Endangered | Wherever found | 06-02-1970 |
| Kaholuamano noctuid moth | Hypena senicula | Resolved Taxon | Wherever found | |
| Kaibab bladderpod | Lesquerella kaibabensis | Not Listed | | |
| Kaibab paintbrush | Castilleja kaibabensis | Resolved Taxon | Wherever found | |
| Kaibab plains cactus | Pediocactus paradinei | Resolved Taxon | Wherever found | |
| Kaiparowits milk-vetch | Astragalus malacoides | Resolved Taxon | Wherever found | |
| Kaiser-I-Hind swallowtail butterfly | Teinopalpus imperialis | Candidate | Wherever found | |
| Kakapo | Strigops habroptilus | Endangered | Wherever found | 06-02-1970 |
| Kalinowski's tinamou | Nothoprocta kalinowskii | Status Undefined | Wherever found | |
| Kaluga sturgeon | Huso dauricus | Endangered | Wherever found | 09-04-2014 |
| Kamakahala | Labordia cyrtandrae | Endangered | Wherever found | 10-10-1996 |
| Kamakahala | Labordia fagraeoidea fagraeoidea | Resolved Taxon | Wherever found | |
| Kamakahala | Labordia helleri | Endangered | Wherever found | 05-13-2010 |
| Kamakahala | Labordia lydgatei | Endangered | Wherever found | 09-20-1991 |
| Kamakahala | Labordia pumila | Endangered | Wherever found | 05-13-2010 |
| Kamakahala | Labordia tinifolia var. lanaiensis | Endangered | Wherever found | 09-03-1999 |
| Kamakahala | Labordia tinifolia var. wahiawaensis | Endangered | Wherever found | 10-10-1996 |
| Kamakahala | Labordia triflora | Endangered | Wherever found | 09-03-1999 |
| Kamanomano | Cenchrus agrimonioides | Endangered | Wherever found | 10-10-1996 |
| Kamapua`a | Kadua fluviatilis | Endangered | Wherever found | 10-31-2016 |
| Kamchatka Point manzanita | Arctostaphylos uva-ursi suborbiculata | Resolved Taxon | Wherever found | |
| Kanab ambersnail | Oxyloma haydeni kanabensis | Original Data in Error - Not a listable entity | Wherever found | 08-08-1991 |
| Kanawha minnow | Phenacobius teretulus | Species of Concern | Wherever found | |
| Kandy Parachute Spider | Poecilotheria smithi | Endangered | Wherever found | 08-30-2018 |
| Kankakee globe-mallow | Iliamna remota | Species of Concern | Wherever found | |
| Kansas aschisma moss | Aschisma kansanum | Resolved Taxon | Wherever found | |
| Kansas bog lemming | Synaptomys cooperi paludis | Resolved Taxon | Wherever found | |
| Kansas Planarian | Sphalloplana kansensis | Resolved Taxon | Wherever found | |
| Kansas well amphipod | Bactrurus hubrichti | Resolved Taxon | Wherever found | |
| Kapu melicope | Melicope radiata | Resolved Taxon | Wherever found | |
| Karner blue butterfly | Lycaeides melissa samuelis | Endangered | Wherever found | 12-14-1992 |
| Karok hesperian | Vespericola karokorum | Resolved Taxon | Wherever found | |
| Karst pond xyris | Xyris longisepala | Under Review | Wherever found | |
| Karst snowfly | Allocapnia cunninghami | Under Review | Wherever found | |
| Kashmir stag | Cervus elaphus hanglu | Endangered | Wherever found | 06-02-1970 |
| Kate's-mountain clover | Trifolium virginicum | Resolved Taxon | Wherever found | |
| Kauai `ahakea long-horned beetle | Plagithmysus permundus | Species of Concern | Wherever found | |
| Kauai akialoa (honeycreeper) | Akialoa stejnegeri | Extinction | Wherever found | 03-11-1967 |
| Kaua'i 'Amakihi | Chlorodrepanis stejnegeri | Species of Concern | Wherever found | |
| Kauai annectant long-horned beetle | Plagithmysus annectans | Species of Concern | Wherever found | |
| Kauai band-legged seed bug | Neseis alternata | Species of Concern | Wherever found | |
| Kauai cave amphipod | Spelaeorchestia koloana | Endangered | Wherever found | 01-14-2000 |
| Kauai cave wolf or pe'e pe'e maka 'ole spider | Adelocosa anops | Endangered | Wherever found | 01-14-2000 |
| Kauai disenochus ground beetle | Disenochus micantipennis | Species of Concern | Wherever found | |
| Kauai Elepaio | Chasiempis sclateri | Species of Concern | Wherever found | |
| Kauai eopenthes click beetle | Eopenthes kauaiensis | Species of Concern | Wherever found | |
| Kauai flightless stag beetle | Apterocyclus honoluluensis | Species of Concern | Wherever found | |
| Kauai forest rhyncogonus weevil | Rhyncogonus sylvicola | Species of Concern | Wherever found | |
| Kauai hau kuahiwi | Hibiscadelphus distans | Endangered | Wherever found | 04-29-1986 |
| Kauai holio long-horned beetle | Plagithmysus polystictus | Species of Concern | Wherever found | |
| Kauai kalia long-horned beetle | Plagithmysus ignotus | Species of Concern | Wherever found | |
| Kauai naenae philodoria moth | Philodoria naenaeiella | Species of Concern | Wherever found | |
| Kauai nesomimesan sphecid wasp | Nesomimesa kauaiensis | Species of Concern | Wherever found | |
| Kauai nesotocus weevil | Nesotocus kauaiensis | Species of Concern | Wherever found | |
| Kauai nukupuu | Hemignathus hanapepe | Extinction | Wherever found | 03-11-1967 |
| Kauai `o`o (honeyeater) | Moho braccatus | Extinction | Wherever found | 03-11-1967 |
| Kauai parti-colored oliarus planthopper | Oliarus consimilis | Species of Concern | Wherever found | |
| Kauai swamp long-horned beetle | Plagithmysus paludis | Species of Concern | Wherever found | |
| Kauai thinfooted bush cricket | Thaumatogryllus variegatus | Species of Concern | Wherever found | |
| Kauai yellow-faced bee | Hylaeus kauaiensis | Species of Concern | Wherever found | |
| Kauila | Alphitonia ponderosa | Resolved Taxon | Wherever found | |
| Kauila | Colubrina oppositifolia | Endangered | Wherever found | 03-04-1994 |
| Kaulu | Pteralyxia kauaiensis | Endangered | Wherever found | 02-25-1994 |
| Kaulu | Pteralyxia laurifolia | Resolved Taxon | Wherever found | |
| Kaulu | Pteralyxia macrocarpa | Endangered | Wherever found | 10-18-2012 |
| Kaumana Cave cricket | Caconemobius varius | Species of Concern | Wherever found | |
| Kawa`u | Zanthoxylum dipetalum dipetalum | Resolved Taxon | Wherever found | |
| Kaweah brodiaea | Brodiaea insignis | Species of Concern | Wherever found | |
| Kaweah Lakes fawn-lily | Erythronium grandiflorum pusateri | Resolved Taxon | Wherever found | |
| Kaweah monkeyflower | Mimulus norrisii | Resolved Taxon | Wherever found | |
| Kaw Whitelip | Webbhelix chadwicki | Resolved Taxon | Wherever found | |
| Kay Gramma | Bouteloua kayi | Not Listed | | |
| Keanae nesosydne planthopper | Nesosydne sulcata | Species of Concern | Wherever found | |
| Kearney's blue-star | Amsonia kearneyana | Endangered | Wherever found | 01-19-1989 |
| Kearney's sumac | Rhus kearneyi | Resolved Taxon | Wherever found | |
| Keck's beardtongue | Penstemon leiophyllus var. keckii | Resolved Taxon | Wherever found | |
| Keck's Checker-mallow | Sidalcea keckii | Endangered | Wherever found | 02-16-2000 |
| Keeled bladderpod | Lesquerella carinata | Species of Concern | Wherever found | |
| Keeled Mountainsnail | Oreohelix carinifera | Resolved Taxon | Wherever found | |
| Keeled sideband | Monadenia circumcarinata | Species of Concern | Wherever found | |
| Keen's myotis | myotis keenii | Species of Concern | Wherever found | |
| Keever's bristle-moss | Orthotrichum keeverae | Species of Concern | Wherever found | |
| Kelso Creek monkey-flower | Mimulus shevockii | Resolved Taxon | Wherever found | |
| Kelso Dune glaresis scarab | Glaresis arenata | Species of Concern | Wherever found | |
| Kelso giant sand treader cricket | Macrobaenetes kelsoensis | Species of Concern | Wherever found | |
| Kelso jerusalem cricket | Ammopelmatus kelsoensis | Species of Concern | Wherever found | |
| Kemp's ridley sea turtle | Lepidochelys kempii | Endangered | Wherever found | 12-02-1970 |
| Kendall's yucca skipper butterfly | Megathymus coloradensis kendalli | Resolved Taxon | Wherever found | |
| Kendall Warm Springs dace | Rhinichthys osculus thermalis | Endangered | Wherever found | 10-13-1970 |
| Kenk's amphipod | Stygobromus kenki | Resolved Taxon | Wherever found | |
| Kentucky arrow darter | Etheostoma spilotum | Threatened | Wherever found | 11-04-2016 |
| Kentucky cave shrimp | Palaemonias ganteri | Endangered | Wherever found | 10-12-1983 |
| Kentucky creekshell | Villosa ortmanni | Proposed Endangered | Wherever found | |
| Kentucky glade cress | Leavenworthia exigua laciniata | Threatened | Wherever found | 06-05-2014 |
| Kentucky red-backed vole | Clethrionomys gapperi maurus | Species of Concern | Wherever found | |
| Kentucky Warbler | Geothlypis formosa | Species of Concern | Wherever found | |
| Kenwood Marsh checker-mallow | Sidalcea oregana ssp. valida | Endangered | Wherever found | 10-22-1997 |
| Kern brook lamprey | Lampetra hubbsi | Resolved Taxon | Wherever found | |
| Kern Canyon slender salamander | Batrachoseps simatus | Proposed Threatened | Wherever found | |
| Kern mallow | Eremalche kernensis | Endangered | Wherever found | 07-19-1990 |
| Kern Plateau salamander | Batrachoseps robustus | Resolved Taxon | Wherever found | |
| Kern primrose sphinx moth | Euproserpinus euterpe | Threatened | Wherever found | 04-08-1980 |
| Kern River daisy | Erigeron multiceps | Species of Concern | Wherever found | |
| Kern River rainbow trout | Oncorhynchus mykiss gilberti | Species of Concern | Wherever found | |
| Kern shoulderband | Helminthoglypta callistoderma | Species of Concern | Wherever found | |
| Kernville poppy | Eschscholzia procera | Species of Concern | Wherever found | |
| Kerr crowfoot | Ranunculus fascicularis cuneiformis | Resolved Taxon | Wherever found | |
| Kerr's agrotis noctuid moth | Agrotis kerri | Resolved Taxon | Wherever found | |
| Kerr's milk-vetch | Astragalus kerrii | Species of Concern | Wherever found | |
| Key deer | Odocoileus virginianus clavium | Endangered | Wherever found | 03-11-1967 |
| Key gnaphosid spider | Cesonia irvingi | Species of Concern | Wherever found | |
| Key Largo cotton mouse | Peromyscus gossypinus allapaticola | Endangered | Wherever found | 09-21-1983 |
| Key Largo woodrat | Neotoma floridana smalli | Endangered | Wherever found | 09-21-1983 |
| Key ring-necked snake | Diadophis punctatus acricus | Proposed Endangered | Wherever found | |
| Keys scaly cricket | Cycloptilum irregularis | Species of Concern | Wherever found | |
| Keys shortwinged conehead katydid | Belocephalus sleighti | Species of Concern | Wherever found | |
| Key striped mud turtle | Kinosternon bauri | Not Listed | Wherever found | |
| Keys vertigo | Vertigo hebardi | Species of Concern | Wherever found | |
| Key tree cactus | Pilosocereus robinii | Endangered | | 07-19-1984 |
| Key Vaca raccoon | Procyon lotor auspicatus | Species of Concern | Wherever found | |
| Key West raccoon | Procyon lotor incautus | Species of Concern | Wherever found | |
| Kiamichi Crayfish | Orconectes saxatilis | Resolved Taxon | Wherever found | |
| Kidneyshell | Ptychobranchus fasciolaris | Not Listed | | |
| Kilauea naupaka | Scaevola kilaueae | Resolved Taxon | Wherever found | |
| Kilauea pa`iniu omoides moth | Omoides iridias | Species of Concern | Wherever found | |
| Killer whale | Orcinus orca | Endangered | Southern Resident DPS See 50 CFR 224.101 | 02-16-2006 |
| Kincaid's Lupine | Lupinus sulphureus ssp. kincaidii | Threatened | Wherever found | 01-25-2000 |
| Kingman springsnail | Pyrgulopsis conica | Under Review | Wherever found | |
| King Rail | Rallus elegans | Species of Concern | Wherever found | |
| King's beardtongue | Penstemon kingii | Resolved Taxon | Wherever found | |
| Kings Canyon cryptochian caddisfly | Cryptochia excella | Species of Concern | Wherever found | |
| King's Creek ecclisomyian caddisfly | Ecclisomyia bilera | Species of Concern | Wherever found | |
| King's Creek parapsyche caddisfly | Parapsyche extensa | Species of Concern | Wherever found | |
| King's gold | Tropidocarpum californicum | Not Listed | | |
| Kings River pyrg | Pyrgulopsis imperialis | Under Review | | |
| Kings River slender salamander | Batrachoseps regius | Resolved Taxon | Wherever found | |
| Kingston bedstraw | Galium hilendiae kingstonense | Species of Concern | Wherever found | |
| Kingston Mountains cinquefoil | Ivesia patellifera | Species of Concern | Wherever found | |
| Kingston Oregonian | Cryptomastix sanburni | Resolved Taxon | Wherever found | |
| Kintla Lake mountain snail | Oreohelix speciessix | Under Review | Wherever found | |
| Kio`ele | Kadua coriacea | Endangered | Wherever found | 05-15-1992 |
| Kiponapona | Phyllostegia racemosa | Endangered | Wherever found | 10-10-1996 |
| Kirtland's snake | Clonophis kirtlandii | Under Review | Wherever found | |
| Kirtland's Warbler | Setophaga kirtlandii | Recovery | Wherever found | 03-11-1967 |
| Kisatchie painted crayfish | Faxonius maletae | Under Review | Wherever found | |
| Kissimmee sponge | Ephydatia subtilis | Species of Concern | Wherever found | |
| Kitchen Creek Mountain snail | Oreohelix speciesseven | Under Review | Wherever found | |
| Kite's neotrichian micro caddisfly | Neotrichia kitae | Species of Concern | Wherever found | |
| Kittatiny red-backed vole | Clethrionomys gapperi rupicola | Resolved Taxon | Wherever found | |
| Kittlitz's murrelet | Brachyramphus brevirostris | Resolved Taxon | Wherever found | |
| Kiyi | Coregonus kiyi | Species of Concern | Wherever found | |
| Klamath gentian | Gentiana plurisetosa | Species of Concern | Wherever found | |
| Klamath iris | Iris tenax klamathensis | Resolved Taxon | Wherever found | |
| Klamath Lake Sculpin | Cottus princeps | Not Listed | | |
| Klamath Lamprey | Entosphenus similis | Not Listed | | |
| Klamath largescale sucker | Catostomus snyderi | Species of Concern | Wherever found | |
| Klamath limnephilan caddisfly | Limnephilus alconura | Resolved Taxon | Wherever found | |
| Klamath manzanita | Arctostaphylos klamathensis | Species of Concern | Wherever found | |
| Klamath Mountain buckwheat | Eriogonum hirtellum | Resolved Taxon | Wherever found | |
| Klamath Smallscale Sucker | Catostomus rimiculus | Not Listed | | |
| Klamath Speckled Dace | Rhinichthys osculus klamathensis | Not Listed | | |
| Kleberg's saltbush | Atriplex klebergorum | Resolved Taxon | Wherever found | |
| Klein's evening-primrose | Oenothera kleinii | Species of Concern | Wherever found | |
| Knapp's brickellia | Brickellia knappiana | Resolved Taxon | Wherever found | |
| Kneeland Prairie penny-cress | Thlaspi californicum | Endangered | Wherever found | 02-09-2000 |
| Knieskern's Beaked-rush | Rhynchospora knieskernii | Threatened | Wherever found | 07-18-1991 |
| Knobby Rams-horn | Vorticifex sp | Resolved Taxon | Wherever found | |
| Knobby rocksnail | Lithasia curta | Status Undefined | Wherever found | |
| Knob mudalia | Leptoxis minor | Species of Concern | Wherever found | |
| Knotty elimia | Elimia interrupta | Species of Concern | Wherever found | |
| Knotty pebblesnail | Somatogyrus constrictus | Species of Concern | Wherever found | |
| Knowlton's cactus | Pediocactus knowltonii | Endangered | Wherever found | 11-28-1979 |
| Knoxville hydroptilan micro caddisfly | Hydroptila decia | Resolved Taxon | Wherever found | |
| Knudsen dubautia | Dubautia knudsenii knudsenii | Resolved Taxon | Wherever found | |
| Koai`e | Acacia koaia | Species of Concern | Wherever found | |
| Koala | Phascolarctos cinereus | Threatened | Australia | 05-09-2000 |
| Koa shield bug | Coleotichus blackburniae | Species of Concern | Wherever found | |
| Koa yellow-faced bee | Hylaeus koae | Species of Concern | Wherever found | |
| Kobuk locoweed | Oxytropis kobukensis | Resolved Taxon | Wherever found | |
| Koch's pitta | Pitta kochi | Endangered | Wherever found | 06-14-1976 |
| Kodachrome bladderpod | Lesquerella tumulosa | Endangered | Wherever found | 10-06-1993 |
| Kodachrome peppergrass | Lepidium montanum stellae | Resolved Taxon | Wherever found | |
| Koebele's rhyncogonus weevil | Rhyncogonus koebelei | Species of Concern | Wherever found | |
| Koehler's rock-cress | Arabis koehleri koehleri | Species of Concern | Wherever found | |
| Kofa barberry | Berberis harrisoniana | Resolved Taxon | Wherever found | |
| Kohala long-horned beetle | Plagithmysus kohalae | Species of Concern | Wherever found | |
| Kohala Mountain sedge omoides moth | Omoides anastreptoides | Species of Concern | Wherever found | |
| Kohe malama malama o Kanaloa | Kanaloa kahoolawensis | Endangered | Wherever found | 09-03-1999 |
| Koholapehu | Dubautia latifolia | Endangered | Wherever found | 05-13-1992 |
| Kokako (wattlebird) | Callaeas cinerea | Endangered | Wherever found | 06-02-1970 |
| Koki`o | Kokia cookei | Endangered | Wherever found | 11-29-1979 |
| Koki`o | Kokia drynarioides | Endangered | Wherever found | 12-04-1984 |
| Koki`o | Kokia kauaiensis | Endangered | Wherever found | 10-10-1996 |
| Koki`o | Kokia lanceolata | Resolved Taxon | Wherever found | |
| Koki`o ke`oke`o | Hibiscus arnottianus ssp. immaculatus | Endangered | Wherever found | 10-08-1992 |
| Koki`o ke`oke`o | Hibiscus waimeae ssp. hannerae | Endangered | Wherever found | 10-10-1996 |
| Kokrines oxytrope | Oxytropis kokrinensis | Resolved Taxon | Wherever found | |
| Kolea | Myrsine fernseei | Resolved Taxon | Wherever found | |
| Kolea | Myrsine fosbergii | Endangered | Wherever found | 10-31-2016 |
| Kolea | Myrsine juddii | Endangered | Wherever found | 10-10-1996 |
| Kolea | Myrsine knudsenii | Endangered | Wherever found | 05-13-2010 |
| Kolea | Myrsine lanaiensis | Resolved Taxon | Wherever found | |
| Kolea | Myrsine linearifolia | Threatened | Wherever found | 10-10-1996 |
| Kolea | Myrsine mezii | Endangered | Wherever found | 05-13-2010 |
| Kolea | Myrsine petiolata | Resolved Taxon | Wherever found | |
| Kolea | Myrsine vaccinioides | Endangered | Wherever found | 06-27-2013 |
| Kolea | Myrsine wawraea | Resolved Taxon | Wherever found | |
| Komodo Island monitor | Varanus komodoensis | Endangered | Wherever found | 06-14-1976 |
| Kona bittercress | Cardamine flexuosa | Resolved Taxon | Wherever found | |
| Kona giant looper | Scotorythra megalophylla | Resolved Taxon | Wherever found | |
| Kona yellow-faced bee | Hylaeus kona | Species of Concern | Wherever found | |
| Konza Prairie Mayfly | Leptophlebia konza | Resolved Taxon | Wherever found | |
| kookoolau | Bidens hillebrandiana ssp. hillebrandiana | Endangered | Wherever found | 11-29-2013 |
| Ko`oko`olau | Bidens amplectens | Endangered | Wherever found | 10-18-2012 |
| Ko`oko`olau | Bidens campylotheca ssp. campylotheca | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens campylotheca ssp. pentamera | Endangered | Wherever found | 06-27-2013 |
| Ko`oko`olau | Bidens campylotheca ssp. waihoiensis | Endangered | Wherever found | 06-27-2013 |
| Ko`oko`olau | Bidens cervicata | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens conjuncta | Endangered | Wherever found | 06-27-2013 |
| Ko`oko`olau | Bidens degeneri | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens hawaiensis | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens macrocarpa ovatifolia | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens mauiensis | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens menziesii leptodonta | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens micrantha caduca | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens micrantha kaalana | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens micrantha laciniata | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens micrantha ssp. ctenophylla | Endangered | Wherever found | 11-29-2013 |
| Ko`oko`olau | Bidens micrantha ssp. kalealaha | Endangered | Wherever found | 05-15-1992 |
| Ko`oko`olau | Bidens molokaiensis | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens obtusiloba | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens pulchella | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens sandvicensis confusa | Species of Concern | Wherever found | |
| Ko`oko`olau | Bidens sandvicensis ssp. sandvicensis | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens sandwicensis setosa | Resolved Taxon | Wherever found | |
| Ko`oko`olau | Bidens wiebkei | Endangered | Wherever found | 10-08-1992 |
| Ko`olau giant looper | Scotorythra nesiotes | Resolved Taxon | Wherever found | |
| Ko`olau spurwing long-legged fly | Campsicnemus mirabilis | Species of Concern | Wherever found | |
| Ko`oloa`ula | Abutilon menziesii | Endangered | Wherever found | 09-26-1986 |
| kopa | Kadua cordata remyi | Endangered | Wherever found | 09-03-1999 |
| Kopiko | Psychotria grandiflora | Endangered | Wherever found | 05-13-2010 |
| Kopiko | Psychotria hexandra var. oahuensis | Endangered | Wherever found | 10-18-2012 |
| Kopiko | Psychotria hobdyi | Endangered | Wherever found | 05-13-2010 |
| Koster's springsnail | Juturnia kosteri | Endangered | Wherever found | 08-09-2005 |
| Kotzebue's, grass-of-parnassus | Parnassia kotzebuei pumila | Resolved Taxon | Wherever found | |
| Kouprey | Bos sauveli | Endangered | Wherever found | 06-02-1970 |
| Kral's water-plantain | Sagittaria secundifolia | Threatened | Wherever found | 04-13-1990 |
| Kramer's cave beetle | Pseudanophthalmus krameri | Species of Concern | Wherever found | |
| Krauss' long-horned beetle | Plagithmysus kraussi | Species of Concern | Wherever found | |
| Kretschmarr Cave mold beetle | Texamaurops reddelli | Endangered | Wherever found | 09-16-1988 |
| Kruckeberg's jewelflower | Streptanthus morrisonii kruckebergii | Species of Concern | Wherever found | |
| Kruckeberg's swordfern | Polystichum kruckebergii | Resolved Taxon | Wherever found | |
| Krug's white morning-glory | Ipomoea krugii | Species of Concern | Wherever found | |
| Kuahiwi laukahi | Plantago hawaiensis | Endangered | Wherever found | 03-04-1994 |
| Kuahiwi laukahi | Plantago princeps | Endangered | Wherever found | 11-10-1994 |
| Kuawawaenohu | Schiedea lychnoides | Endangered | Wherever found | 10-10-1996 |
| Kuenzler hedgehog cactus | Echinocereus fendleri var. kuenzleri | Threatened | Wherever found | 11-28-1979 |
| Kuhl's (=Bawean) deer | Axis porcinus kuhli | Endangered | Wherever found | 06-02-1970 |
| Kuhns' Oahu long-horned beetle | Plagithmysus kuhnsi | Species of Concern | Wherever found | |
| Kulu`i | Nototrichium humile | Endangered | Wherever found | 10-29-1991 |
| Kupukupu makali`i | Menisciopsis boydiae | Endangered | Wherever found | 10-31-2016 |
| Kusche's nesosydne planthopper | Nesosydne kuschei | Species of Concern | Wherever found | |
| Lace-leaf Rockdaisy | Perityle ambrosiifolia | Resolved Taxon | Wherever found | |
| Lacey's cave pseudoscorpion | Larca laceyi | Species of Concern | Wherever found | |
| Lacy elimia (snail) | Elimia crenatella | Threatened | Wherever found | 10-28-1998 |
| Ladder backed Woodpecker | Picoides scalaris | Species of Concern | Wherever found | |
| Ladybug Saddle talussnail | Sonorella sp. | Species of Concern | Wherever found | |
| Laetan yellow-faced bee | Hylaeus laeta | Species of Concern | Wherever found | |
| Lagniappe crayfish | Procambarus lagniappe | Not Listed | Wherever found | |
| La Graciosa thistle | Cirsium loncholepis | Endangered | Wherever found | 03-20-2000 |
| Laguna alumroot | Heuchera brevistaminea | Resolved Taxon | Wherever found | |
| Laguna Beach liveforever | Dudleya stolonifera | Threatened | Wherever found | 10-13-1998 |
| Laguna Mountains aster | Machaeranthera asteroides lagunensis | Species of Concern | Wherever found | |
| Laguna Mountains jewelflower | Streptanthus bernardinus | Resolved Taxon | Wherever found | |
| Laguna Mountains skipper | Pyrgus ruralis lagunae | Endangered | Wherever found | 01-16-1997 |
| Laguna Mountains sunflower | Hulsea californica | Resolved Taxon | Wherever found | |
| Lahaina rhyncogonus weevil | Rhyncogonus lahainae | Species of Concern | Wherever found | |
| Lahontan Creek tui chub | Siphateles bicolor obesa | Resolved Taxon | Wherever found | |
| Lahontan cutthroat trout | Oncorhynchus clarkii henshawi | Threatened | Wherever found | 10-13-1970 |
| Lahontan Shiner | Richardsonius egregius | Not Listed | | |
| Lake Alamanor bluecup | Legousia speculum-veneris | Resolved Taxon | Wherever found | |
| Lake Chub | Couesius plumbeus | Not Listed | | |
| Lake Chubsucker | Erimyzon sucetta | Not Listed | | |
| Lake County dwarf-flax | Hesperolinon didymocarpum | Species of Concern | Wherever found | |
| Lake County stonecrop | Parvisedum leiocarpum | Endangered | Wherever found | 06-18-1997 |
| Lake Disc | Discus brunsoni | Resolved Taxon | Wherever found | |
| Lake Erie pinkweed | Polygonum pensylvanicum eglandulosum | Resolved Taxon | Wherever found | |
| Lake Erie water snake | Nerodia sipedon insularum | Recovery | Lake Erie offshore islands and their adjacent waters (located more than 1 mile from mainland)_U.S.A. (OH), Canada (Ont.) | 08-30-1999 |
| Lake Herring | Coregonus artedi | Not Listed | | |
| Lake Huron locust | Trimerotropis huroniana | Species of Concern | Wherever found | |
| Lakela's mint | Dicerandra immaculata | Endangered | | 05-15-1985 |
| Lake Placid funnel wolf spider | Sosippus placidus | Species of Concern | Wherever found | |
| Lakeside ceanothus | Ceanothus cyaneus | Species of Concern | Wherever found | |
| Lakeside daisy | Hymenoxys herbacea | Threatened | Wherever found | 06-23-1988 |
| Lake sturgeon | Acipenser fulvescens | Not Listed | Wherever found | 08-15-2019 |
| Lake Tahoe benthic stonefly | Capnia lacustra | Species of Concern | Wherever found | |
| Lake Trout | Salvelinus namaycush | Not Listed | | |
| Lake Valley pyrg | Pyrgulopsis sublata | Resolved Taxon | Wherever found | |
| Lake Whitefish | Coregonus clupeaformis | Not Listed | | |
| Lallemant's cave beetle | Pseudanophthalmus lallemanti | Species of Concern | Wherever found | |
| Lamarck's Sheet Coral | Agaricia lamarcki | Status Undefined | Wherever found | |
| Lamb Rams-horn | Planorbella oregonensis | Resolved Taxon | Wherever found | |
| Lamotte's Roundleaf Bat | Hipposideros lamottei | Under Review | Wherever found | |
| Lanai kalanian leaf bug | Kalania hawaiiensis | Species of Concern | Wherever found | |
| Lanai `ohi`a long-horned beetle | Plagithmysus lanaiensis | Species of Concern | Wherever found | |
| Lanai oliarus planthopper | Oliarus lanaiensis | Resolved Taxon | Wherever found | |
| Lanai pomace fly | Drosophila lanaiensis | Species of Concern | Wherever found | |
| Lanai rhyncogonus weevil | Rhyncogonus lanaiensis | Species of Concern | Wherever found | |
| Lanai sandalwood (=`iliahi) | Santalum haleakalae var. lanaiense | Endangered | Wherever found | 01-24-1986 |
| Lanai tree snail | Partulina crassa | Species of Concern | Wherever found | |
| Lanai tree snail | Partulina semicarinata | Endangered | Wherever found | 06-27-2013 |
| Lanai tree snail | Partulina variabilis | Endangered | Wherever found | 06-27-2013 |
| Lanai yellow-faced bee | Hylaeus angustula | Resolved Taxon | Wherever found | |
| Lance leaf wild-buckwheat | Eriogonum lancifolium | Resolved Taxon | Wherever found | |
| Landyes pyrg | Pyrgulopsis landyei | Under Review | Wherever found | |
| Lane Mountain milk-vetch | Astragalus jaegerianus | Endangered | Wherever found | 10-06-1998 |
| Lange's El Segundo Dune weevil | Onychobaris langei | Species of Concern | Wherever found | |
| Lange's metalmark butterfly | Apodemia mormo langei | Endangered | Wherever found | 06-08-1976 |
| Langford's tree snail | Partula langfordi | Endangered | Wherever found | 11-02-2015 |
| Langston's blue butterfly | Euphilotes enoptes langstoni | Resolved Taxon | Wherever found | |
| Lanyu Scops owl | Otus elegans botelensis | Resolved Taxon | Wherever found | |
| Laramie columbine | Aquilegia laramiensis | Species of Concern | Wherever found | |
| Laramie false sagebrush | Sphaeromeria simplex | Species of Concern | Wherever found | |
| Larch Mountain salamander | Plethodon larselli | Resolved Taxon | Wherever found | |
| Large aegialian scarab | Aegialia magnifica | Resolved Taxon | Wherever found | |
| Large-billed savannah sparrow | Passerculus sandwichensis rostratus | Species of Concern | Wherever found | |
| Large-blotched ensatina | Ensatina eschscholtzii klauberi | Species of Concern | Wherever found | |
| Large desert marsupial-mouse | Sminthopsis psammophila | Endangered | Wherever found | 12-02-1970 |
| Large-eared hutia | Capromys auritus | Endangered | Wherever found | 05-16-1986 |
| Large-flowered Barbara's buttons | Marshallia grandiflora | Under Review | Wherever found | |
| Large-flowered fiddleneck | Amsinckia grandiflora | Endangered | Wherever found | 05-08-1985 |
| Large-flowered skullcap | Scutellaria montana | Threatened | Wherever found | 06-20-1986 |
| Large-flowered woolly meadowfoam | Limnanthes pumila ssp. grandiflora | Endangered | Wherever found | 11-07-2002 |
| Large-fruited bladder-pod | Lesquerella macrocarpa | Species of Concern | Wherever found | |
| Large-fruited sand-verbena | Abronia macrocarpa | Endangered | Wherever found | 09-28-1988 |
| Large Kauai (=kamao) Thrush | Myadestes myadestinus | Extinction | Wherever found | 10-13-1970 |
| Largeleaf grass of Parnassus | Parnassia grandifolia | Species of Concern | Wherever found | |
| Large-leaved filaree | erodium macrophyllum | Species of Concern | Wherever found | |
| Large-leaved jointweed | Polygonella macrophylla | Species of Concern | Wherever found | |
| large marble butterfly | Euchloe ausonides | Under Review | | |
| Largemouth Bass | Micropterus salmoides | Not Listed | | |
| Largemouthed leatherskin | Scomberoides lysan | Not Listed | | |
| Large-petaled ash | Fraxinus cuspidata macropetala | Resolved Taxon | Wherever found | |
| Large red buckwheat | Eriogonum grande rubescens | Species of Concern | Wherever found | |
| Largescaled Spinycheek Sleeper | Eleotris amblyopsis | Not Listed | | |
| largescale sucker | Catostomus macrocheilus | Status Undefined | Wherever found | |
| Large Shovelnose Sturgeon | Pseudoscaphirhynchus kaufmanni | Under Review | Wherever found | |
| Large-spotted leopard lizard | gambelia wislizenii ssp. wislizenii | Species of Concern | Wherever found | |
| Largetooth Sawfish | Pristis pristis | Endangered | Wherever found | 07-23-2014 |
| Laricis tree cricket | Oecanthus laricis | Species of Concern | Wherever found | |
| Lark Bunting | Calamospiza melanocorys | Species of Concern | Wherever found | |
| Lark Sparrow | Chondestes grammacus | Species of Concern | Wherever found | |
| Larkspur | Delphinium leucophaeum | Species of Concern | Wherever found | |
| Lar Valley viper | Vipera latifii | Endangered | Wherever found | 06-22-1983 |
| La Sal pika | Ochotona princeps lasalensis | Species of Concern | Wherever found | |
| Las Animas colubrina | Colubrina californica | Resolved Taxon | Wherever found | |
| Lassen County bluegrass | Poa X limosa | Resolved Taxon | Wherever found | |
| Lassen desert-parsley | Lomatium ravenii | Resolved Taxon | Wherever found | |
| Lassics lupine | Lupinus constancei | Endangered | | 11-06-2023 |
| Last Chance townsendia | Townsendia aprica | Threatened | Wherever found | 08-21-1985 |
| Las Vegas bearpoppy | Arctomecon californica | Resolved Taxon | | |
| Las Vegas buckwheat | Eriogonum corymbosum var. nilesii | Resolved Taxon | Wherever found | |
| Las Vegas dace | Rhinichthys deaconi | Resolved Taxon | Wherever found | |
| Lateral bluet | Enallagma laterale | Species of Concern | Wherever found | |
| Lau `ehu | Panicum niihauense | Endangered | Wherever found | 10-10-1996 |
| Laughing gull | larus atricilla | Species of Concern | Wherever found | |
| Laulihilihi | Schiedea stellarioides | Endangered | Wherever found | 10-10-1996 |
| Laurel dace | Chrosomus saylori | Endangered | Wherever found | 09-08-2011 |
| Lava rock mountainsnail | Oreohelix waltoni | Species of Concern | Wherever found | |
| Lavin's milk-vetch | Astragalus oophorus lavinii | Species of Concern | Wherever found | |
| Lawrence's Goldfinch | Spinus lawrencei | Species of Concern | Wherever found | |
| Layne's butterweed | Senecio layneae | Threatened | Wherever found | 10-18-1996 |
| Laysan agrotis noctuid moth | Agrotis laysanensis | Resolved Taxon | Wherever found | |
| Laysan Albatross | Phoebastria immutabilis | Species of Concern | | |
| Laysan dropseed noctuid moth | Hypena laysanensis | Resolved Taxon | Wherever found | |
| Laysan duck | Anas laysanensis | Endangered | Wherever found | 03-11-1967 |
| Laysan finch | Telespiza cantans | Endangered | Wherever found | 03-11-1967 |
| Laysan hedyleptan moth | Hedylepta laysanensis | Resolved Taxon | Wherever found | |
| Laysan oodemas weevil | Oodemas laysanensis | Species of Concern | Wherever found | |
| Laysan rhyncogonus weevil | Rhyncogonus bryani | Species of Concern | Wherever found | |
| Lazuli Bunting | Passerina amoena | Species of Concern | Wherever found | |
| Leach's Storm-Petrel | Oceanodroma leucorhoa | Species of Concern | Wherever found | |
| Leadbeater's Possum | Gymnobelideus leadbeateri | Endangered | Wherever found | 05-16-1986 |
| Leafshell | Epioblasma flexuosa | Resolved Taxon | Wherever found | |
| Leafy prairie-clover | Dalea foliosa | Endangered | | 05-01-1991 |
| Leafy reedgrass | Calamagrostis foliosa | Resolved Taxon | Wherever found | |
| Lean crayfish | Cambarus strigosus | Status Undefined | Wherever found | |
| Lea's Bog lichen | Phaeophyscia leana | Status Undefined | | |
| Least Bell's vireo | Vireo bellii pusillus | Endangered | Wherever found | 05-02-1986 |
| Least bittern | Ixobrychus exilis | Species of Concern | Wherever found | |
| Least Brook Lamprey | Lampetra aepyptera | Not Listed | | |
| Least chub | Iotichthys phlegethontis | Resolved Taxon | Wherever found | |
| Least Cisco | Coregonus sardinella | Not Listed | | |
| Least crayfish | Cambarellus diminutus | Not Listed | Wherever found | |
| Least Darter | Etheostoma microperca | Not Listed | | |
| Least Madtom | Noturus hildebrandi | Not Listed | | |
| Least, Ozark trillium | Trillium pusillum ozarkanum | Species of Concern | Wherever found | |
| Least Storm-Petrel | Oceanodroma microsoma | Species of Concern | | |
| Least tern | Sternula antillarum | Recovery | U.S.A. (AR, CO, IA, IL, IN, KS, KY, LA_Miss. R. and tribs. N of Baton Rouge, MS_Miss. R., MO, MT, ND, NE, NM, OK, SD, TN, TX_except within 50 miles of coast) | 05-28-1985 |
| Least tern | Sternula antillarum | Species of Concern | Atlantic | |
| Least Tern | Sternula antillarum antillarum | Species of Concern | | |
| Least Tern | Sternula antillarum athalassos | Species of Concern | | |
| Least, Virginia trillium | Trillium pusillum virginianum | Species of Concern | Wherever found | |
| Leatherback sea turtle | Dermochelys coriacea | Endangered | Wherever found | 06-02-1970 |
| Leatherside chub | Snyderichthys copei | Species of Concern | Wherever found | |
| Le Conte's Sparrow | Ammospiza leconteii | Species of Concern | Wherever found | |
| LeConte''s Thrasher | Toxostoma lecontei | Species of Concern | Wherever found | |
| Leech's chaetarthrian water scavenger beetle | Chaetarthria leechi | Species of Concern | Wherever found | |
| Leech's skyline diving beetle | Hydroporus leechi | Species of Concern | Wherever found | |
| Lee County cave isopod | Lirceus usdagalun | Endangered | Wherever found | 11-20-1992 |
| Leedy's roseroot | Rhodiola integrifolia ssp. leedyi | Threatened | Wherever found | 04-22-1992 |
| Lee pincushion cactus | Coryphantha sneedii var. leei | Threatened | Wherever found | 11-26-1979 |
| Lee's micro-blind harvestman | Microcina leei | Species of Concern | Wherever found | |
| Lefevre's pearly mussel | Epioblasma lefevrei | Resolved Taxon | Wherever found | |
| Legenere | Legenere limosa | Species of Concern | Wherever found | |
| lehua makanoe | Lysimachia daphnoides | Endangered | Wherever found | 05-13-2010 |
| Leichtlin camassia | Camassia leichtlinii leichtlinii | Resolved Taxon | Wherever found | |
| Le`ie rhyncogonus weevil | Rhyncogonus freycinetiae | Species of Concern | Wherever found | |
| Lemhi beardtongue | Penstemon lemhiensis | Species of Concern | Wherever found | |
| Lemmer's pinnion moth | Lithophane lemmeri | Resolved Taxon | Wherever found | |
| Lemmon fern cloak | Notholaena lemmonii | Species of Concern | Wherever found | |
| Lemmon fleabane | Erigeron lemmonii | Resolved Taxon | Wherever found | |
| Lemmon globe berry | Physalis solanaceus | Species of Concern | Wherever found | |
| Lemmon's clover | Trifolium lemmonii | Resolved Taxon | Wherever found | |
| Lemmon's jewelflower | Streptanthus lemmonii | Species of Concern | Wherever found | |
| Lemmon's Lupine | Lupinus lemmonii | Resolved Taxon | Wherever found | |
| Lemmon's morning-glory | Ipomoea tenuiloba lemmonii | Resolved Taxon | Wherever found | |
| Lemmon's paintbrush | Castilleja lemmonii | Resolved Taxon | Wherever found | |
| Lemon colored fawn-lily | Erythronium citrinum rodrickii | Species of Concern | Wherever found | |
| Lemon lily | Lilium parryi | Species of Concern | Wherever found | |
| Lemurs | Lemuridae (incl. genera Lemur, Phaner, Hapalemur, Lepilemur, Microcebus, Allocebus, Cheirogaleus, Varecia) | Endangered | Wherever found | 06-02-1970 |
| Lenat's ceraclean caddisfly | Ceraclea sp. | Species of Concern | Wherever found | |
| Leo Brewer's manzanita | Arctostaphylos uva-ursi leobreweri | Resolved Taxon | Wherever found | |
| Leona's little blue butterfly | Philotiella leona | Resolved Taxon | Wherever found | |
| Leoncita false-foxglove | Agalinis calycina | Under Review | Wherever found | |
| Leon River winter stonefly | Taeniopteryx starki | Resolved Taxon | Wherever found | |
| Leon Springs pupfish | Cyprinodon bovinus | Endangered | Wherever found | 08-15-1980 |
| Leopard | Panthera pardus | Endangered | Wherever found, except where it is listed as Threatened | 06-02-1970 |
| Leopard | Panthera pardus | Threatened | In Africa, in the wild, south of, and including, the following countries: Gabon, Congo, Zaire, Uganda, Kenya | 01-28-1982 |
| Leopard cat | Prionailurus (=Felis) bengalensis bengalensis | Endangered | Wherever found | 06-14-1976 |
| Leopard Dace | Rhinichthys falcatus | Not Listed | | |
| Leopard darter | Percina pantherina | Threatened | Wherever found | 02-27-1978 |
| Leopard Shark | Triakis semifasciata | Not Listed | | |
| leslis canyon talussnail | sonorella pedregosensis | Resolved Taxon | Wherever found | |
| Lesser Adams Cave beetle | Pseudanophthalmus catorycetes | Resolved Taxon | Wherever found | |
| Lesser Common Nighthawk | Chordeiles minor minor | Species of Concern | | |
| Lesser long-nosed bat | Leptonycteris curasoae yerbabuenae | Recovery | Wherever found | 09-30-1988 |
| Lesser nighthawk | chordeiles acutipennis | Species of Concern | Wherever found | |
| Lesser prairie-chicken | Tympanuchus pallidicinctus | Endangered | Southern DPS: All lesser prairie-chickens south of a line starting at 37.9868 N, 105.0133 W, and ending at 31.7351 N, 98.3773 W, NAD83 | 03-27-2023 |
| Lesser prairie-chicken | Tympanuchus pallidicinctus | Threatened | Northern DPS: All lesser prairie-chickens north of a line starting at 37.9868 N, 105.0133 W, and ending at 31.7351 N, 98.3773 W, NAD83 | 03-27-2023 |
| Lesser prairie-chicken | Tympanuchus pallidicinctus | Under Review | Wherever found | 05-12-2014 |
| Lesser rabbit bandicoot | Macrotis leucura | Endangered | Wherever found | 12-02-1970 |
| Lesser rhea (incl. Darwin's) | Rhea (=Pterocnemia) pennata | Endangered | Wherever found | 06-02-1970 |
| Lesser Saint Croix Skink | Capitellum parvicruzae | Resolved Taxon | Wherever found | |
| Lesser saltbrush | atriplex minuscula | Species of Concern | Wherever found | |
| Lesser scaup | Aythya affinis | Species of Concern | Wherever found | |
| Lesser Siren | Siren intermedia | Not Listed | | |
| Lesser slender salamander | Batrachoseps minor | Status Undefined | Wherever found | |
| Lesser slow loris | Nycticebus pygmaeus | Threatened | Wherever found | 10-19-1976 |
| Lesser Virgin Islands Skink | Spondylurus semitaeniatus | Proposed Endangered | Wherever found | |
| Lesser White-cheeked Pintail | Anas bahamensis bahamensis | Species of Concern | Wherever found | |
| Lesser Yellowlegs | Tringa flavipes | Species of Concern | Wherever found | |
| Lesueur's rat-kangaroo | Bettongia lesueur | Endangered | Wherever found | 12-02-1970 |
| Lewis's Woodpecker | Melanerpes lewis | Species of Concern | Wherever found | |
| Lewton's polygala | Polygala lewtonii | Endangered | | 04-27-1993 |
| L'hoest's monkey | Cercopithecus lhoesti | Endangered | Wherever found | 10-19-1976 |
| Light-footed Ridgway''s rail | Rallus obsoletus levipes | Endangered | Wherever found | 10-13-1970 |
| Lihue oliarus planthopper | Oliarus lihue | Species of Concern | Wherever found | |
| Lilia de los llanos | Echeandia chandleri | Species of Concern | Wherever found | |
| Liliwai | Acaena exigua | Endangered | Wherever found | 05-15-1992 |
| Lilliput | Toxolasma parvum | Not Listed | | |
| Lily Shoals elimia | Elimia annettae | Under Review | Wherever found | |
| Limestone cave beetle | Pseudanophthalmus calcareus | Species of Concern | Wherever found | |
| Limestone fameflower | Talinum calcaricum | Resolved Taxon | Wherever found | |
| Limestone penstemon | Penstemon calcareus | Resolved Taxon | Wherever found | |
| Limestone rosewood | Vauquelinia californica pauciflora | Species of Concern | Wherever found | |
| Limestone salamander | Hydromantes brunus | Under Review | Wherever found | |
| Limestone violet | Viola purpurea charlestonensis | Resolved Taxon | Wherever found | |
| Limestone wild-buckwheat | Eriogonum eremicum | Resolved Taxon | Wherever found | |
| Limpia Creek pocket gopher | Thomomys umbrinus texensis | Species of Concern | Wherever found | |
| Limpia Creek Springsnail | Pyrgulopsis davisi | Under Review | Wherever found | |
| Limpia southern pocket gopher | Thomomys umbrinus limpiae | Species of Concern | Wherever found | |
| Limpkin | Aramus guarauna elucus | Species of Concern | Wherever found | |
| Lincoln County bladder-pod | Lesquerella lata | Resolved Taxon | Wherever found | |
| Lincoln's Sparrow | Melospiza lincolnii | Species of Concern | Wherever found | |
| Linda's Roadside-skipper | Amblyscirtes linda | Under Review | Wherever found | |
| Lindheimer's nailwort | Paronychia lindheimeri var. lindheimeri | Resolved Taxon | Wherever found | |
| Lindheimer's tickseed | Desmodium lindheimeri | Species of Concern | Wherever found | |
| Lined chub | Hybopsis lineapunctata | Resolved Taxon | Wherever found | |
| Lined pocketbook | Lampsilis binominata | Species of Concern | Wherever found | |
| Linville Caverns Spider | Nesticus carolinensis | Species of Concern | | |
| Lion | Panthera leo ssp. leo | Endangered | Wherever found | 01-22-2016 |
| Lion | Panthera leo ssp. melanochaita | Threatened | Wherever found | 01-22-2016 |
| Lion-tailed macaque | Macaca silenus | Endangered | Wherever found | 06-02-1970 |
| lipstick darter | Etheostoma chuckwachatte | Species of Concern | Wherever found | |
| Little Aguja (=Creek) Pondweed | Potamogeton clystocarpus | Endangered | Wherever found | 11-14-1991 |
| Little amphianthus | Amphianthus pusillus | Threatened | Wherever found | 02-05-1988 |
| Little Blue Heron | Egretta caerulea | Species of Concern | Wherever found | |
| Little blue macaw | Cyanopsitta spixii | Endangered | Wherever found | 06-14-1976 |
| Little Bluestem | Schizachyrium scoparium | Not Listed | | |
| Little brown bat | Myotis lucifugus | Under Review | Wherever found | |
| Little Colorado spinedace | Lepidomeda vittata | Threatened | Wherever found | 03-11-1967 |
| Little Colordao River sucker | Catostomus | Not Listed | | |
| Little earth hutia | Capromys sanfelipensis | Endangered | Wherever found | 05-16-1986 |
| Little Kennedy cave beetle | Pseudanophthalmus cordicollis | Resolved Taxon | Wherever found | |
| Little Kern golden Trout | Oncorhynchus aguabonita whitei | Threatened | Wherever found | 05-15-1978 |
| Little Lake speckled dace | Rhinichthys osculus ssp. | Resolved Taxon | Little Lake | |
| Little-leaf brongniartia | Brongniartia minutifolia | Species of Concern | Wherever found | |
| Little Mariana fruit Bat | Pteropus tokudae | Extinction | Wherever found | 08-27-1984 |
| Little mousetail | Myosurus minimus apus | Species of Concern | Wherever found | |
| Little oecetis longhorn caddisfly | Oecetis parva | Under Review | Wherever found | |
| Little planigale | Planigale ingrami subtilissima | Endangered | Wherever found | 12-02-1970 |
| Little riffle beetle | Dubiraphia parva | Species of Concern | Wherever found | |
| Little River crayfish | Cambarus spicatus | Under Review | Wherever found | |
| Little San Bernardino Mountains gilia | Gilia maculata | Species of Concern | Wherever found | |
| Little San Bernardino Mountains gilia | Linanthus maculates | Status Undefined | Wherever found | |
| Little's fissidens moss | Fissidens littlei | Resolved Taxon | Wherever found | |
| Little Spectacle Case | Villosa lienosa | Not Listed | | |
| Little Sur manzanita | Arctostaphylos edmundsii | Species of Concern | Wherever found | |
| Little Tennessee crayfish | Cambarus georgiae | Status Undefined | Wherever found | |
| Little willow flycatcher | Empidonax traillii brewsteri | Species of Concern | Wherever found | |
| Littlewing pearlymussel | Pegias fabula | Endangered | Wherever found | 11-14-1988 |
| Live Oak Glass | Nesovitrea suzannae | Resolved Taxon | Wherever found | |
| Livermore nailwort | Paronychia monticola | Resolved Taxon | Wherever found | |
| Livermore sandwort | Arenaria livermorensis | Resolved Taxon | Wherever found | |
| Livermore sweet-cicely | Osmorhiza mexicana bipatriata | Species of Concern | Wherever found | |
| Llanero Coqui | Eleutherodactylus juanariveroi | Endangered | Wherever found | 10-04-2012 |
| Lloyd's hedgehog cactus | Echinocereus lloydii | Original Data in Error - Not a listable entity | | 11-28-1979 |
| Lloyd''s Mariposa cactus | Sclerocactus mariposensis | Threatened | Wherever found | 12-06-1979 |
| Loach minnow | Tiaroga cobitis | Endangered | Wherever found | 10-28-1986 |
| Lobed Barren Strawberry | Geum lobatum | Species of Concern | | |
| Lobed roachfly | Tallaperla lobata | Under Review | Wherever found | |
| Lobed Star Coral | Orbicella annularis | Threatened | Wherever found | 11-13-2014 |
| Lobe-wing brown lacewing | Micromus lobipennis | Species of Concern | Wherever found | |
| Loch Lomond coyote thistle | Eryngium constancei | Endangered | Wherever found | 08-01-1985 |
| Lockes pyrg | Pyrgulopsis lockensis | Resolved Taxon | Wherever found | |
| Lodgepole chipmunk | Tamias speciosus speciosus | Species of Concern | Wherever found | |
| Logan's Agarodes caddisfly | Agarodes logani | Under Review | Wherever found | |
| Logan wild-buckwheat | Eriogonum loganum | Resolved Taxon | Wherever found | |
| Loggerhead Kingbird | Tyrannus caudifasciatus | Species of Concern | Wherever found | |
| Loggerhead sea turtle | Caretta caretta | Endangered | Loggerhead sea turtles originating from the South Pacific south of the equator, north of 60 degrees S. Lat., west of 67 degrees W. Long., and east of 141 degrees E. Long. | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Endangered | Mediterranean Sea DPS - Loggerhead sea turtles originating from the Mediterranean Sea east of 5 degrees 36 minues W. Long. | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Endangered | Northeast Atlantic Ocean DPS - Loggerhead sea turtles originating from the Northeast Atlantic Ocean north of the equator, south of 60 degrees N. Lat., and east of 40 degrees W. Long., except in the vicinity of the Strait of Gibraltar where the eastern boundary is 5 degrees 36 minutes W. Long | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Endangered | North Indian Ocean DPS - Loggerhead sea turtles originating from the North Indian Ocean north of the equator and south of 30? N. Lat | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Endangered | North Pacific Ocean DPS - Loggerhead sea turtles originating from the North Pacific north of the equator and south of 60 degrees N. Lat | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Threatened | Loggerhead sea turtles originating from the South Atlantic Ocean south of the equator, north of 60 degrees S. Lat., west of 20 degrees E. Long., and east of 67 degrees W. Long | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Threatened | Loggerhead sea turtles originating from the Southeast Indian Ocean south of the equator, north of 60 degrees S. Lat., and east of 80 degrees E. Long.; South Pacific Ocean south of the equator, north of 60degrees S. Lat., and west of 141 degrees E. Long | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Threatened | Loggerhead sea turtles originating from the Southwest Indian Ocean north of the equator, south of 30 degrees N. Lat., east of 20 degrees E. Long., and west of 80 degrees E. Long. | 07-23-1978 |
| Loggerhead sea turtle | Caretta caretta | Threatened | Northwest Atlantic Ocean DPS - Loggerhead sea turtles originating from the Northwest Atlantic Ocean west of 40 degrees W. Long | 07-23-1978 |
| Logperch | Percina caprodes | Not Listed | | |
| Loma Prieta hoita | hoita strobilina | Species of Concern | Wherever found | |
| Lompoc grasshopper | Trimerotropis occulens | Resolved Taxon | Wherever found | |
| Lompoc yerba santa | Eriodictyon capitatum | Endangered | Wherever found | 03-20-2000 |
| Lonestar Sandmint | Rhododon angulatus | Not Listed | | |
| Long Beach seedbox | Ludwigia brevipes | Status Undefined | | |
| Long-bearded, Peck's mariposa | Calochortus longebarbatus peckii | Species of Concern | Wherever found | |
| Long-billed Curlew | Numenius americanus | Resolved Taxon | Wherever found | |
| Long-eared myotis | Myotis evotis | Species of Concern | Wherever found | |
| Long-eared Owl | asio otus | Species of Concern | Wherever found | |
| Longear Sunfish | Lepomis megalotis | Not Listed | | |
| Longfin dace | Agosia chrysogaster | Species of Concern | Wherever found | |
| Longfin Smelt | Spirinchus thaleichthys | Endangered | San Francisco Bay-Delta Distinct Population Segment | 08-29-2024 |
| Longfin Smelt | Spirinchus thaleichthys | Not Listed | Wherever Found | |
| Long-footed nesosydne planthopper | Nesosydne longipes | Species of Concern | Wherever found | |
| Long-haired phlox | Phlox pilosa longipilosa | Resolved Taxon | Wherever found | |
| Long-haired star-tulip | Calochortus longebarbatus longebarbatus | Species of Concern | Wherever found | |
| Longhead darter | Percina macrocephala | Resolved Taxon | Wherever found | |
| Long-headed cave beetle | Pseudanophthalmus longiceps | Species of Concern | Wherever found | |
| Longhorn fairy shrimp | Branchinecta longiantenna | Endangered | Wherever found | 09-19-1994 |
| Longitudinal pyrg | Pyrgulopsis anguina | Resolved Taxon | Wherever found | |
| Longjaw cisco | Coregonus alpenae | Extinction | Wherever found | 03-11-1967 |
| Longleaf phlox | Phlox longifolia ssp. longifolia | Resolved Taxon | Wherever found | |
| Long-legged bustard | Sypheotides indica | Status Undefined | Wherever found | |
| Long-legged cave amphipod | Stygobromus longipes | Species of Concern | Wherever found | |
| Long-legged myotis | Myotis volans | Species of Concern | Wherever found | |
| Long-legged warbler | Trichocichla rufa | Endangered | Wherever found | 01-16-2008 |
| Longmouth Pondsnail | Stagnicola elrodiana | Resolved Taxon | Wherever found | |
| Long-necked long-horned beetle | Plagithmysus longicollis | Species of Concern | Wherever found | |
| Longnose darter | Percina nasuta | Under Review | Wherever found | |
| Long-nosed leopard lizard | gambelia wislizenii | Species of Concern | Wherever found | |
| Longnose Gar | Lepisosteus osseus | Not Listed | | |
| longnose sucker | Catostomus catostomus | Status Undefined | Wherever found | |
| Long-petaled lewisia | Lewisia longipetala | Species of Concern | Wherever found | |
| Long's bittercress | Cardamine longii | Resolved Taxon | Wherever found | |
| Long's bulrush | Scirpus longii | Species of Concern | Wherever found | |
| Longsolid | Fusconaia subrotunda | Threatened | Wherever found | 04-10-2023 |
| Long spur columbine | Aquilegia longissima | Species of Concern | Wherever found | |
| Longspurred mint | Dicerandra cornutissima | Endangered | | 11-01-1985 |
| Long-stalked holly | Ilex collina | Resolved Taxon | Wherever found | |
| Longstreet Spring snail | Fluminicola sp. | Resolved Taxon | Wherever found | |
| Long-tailed caddisfly | Farula sp. | Species of Concern | Wherever found | |
| Long-tailed chinchilla | Chinchilla lanigera | Under Review | Wherever found | |
| Long-tailed Duck | Clangula hyemalis | Resolved Taxon | Wherever found | |
| Long-tailed ground roller | Uratelornis chimaera | Endangered | Wherever found | 06-02-1970 |
| Long-tailed langur | Presbytis potenziani | Threatened | Indonesia | 10-19-1976 |
| Long-tailed macaque | Macaca fascicularis | Not Listed | | |
| Long-tailed marsupial-mouse | Sminthopsis longicaudata | Endangered | Wherever found | 12-02-1970 |
| Long-tailed otter | Lontra (=Lutra) longicaudis (incl. platensis) | Endangered | Wherever found | 06-02-1970 |
| Long-tailed pangolin | Manis tetradactyla | Under Review | Wherever found | |
| Long-tailed shrew | Sorex dispar | Resolved Taxon | Wherever found | |
| Long Valley milk-vetch | Astragalus johannis-howellii | Resolved Taxon | Wherever found | |
| Long Valley speckled dace | Rhinichthys nevadensis caldera | Proposed Endangered | Long Valley | |
| loopy five firefly | Photuris forresti | Not Listed | | |
| Lora Aborn's moth | Lorita abornana | Resolved Taxon | Wherever found | |
| Lord Howe Long-Eared Bat | Nyctophilus howensis | Under Review | Wherever found | |
| Lord Howe pied currawong | Strepera graculina crissalis | Candidate | Wherever found | |
| Lord Howe wood rail | Gallirallus (=Tricholimnas) sylvestris | Endangered | Wherever found | 06-14-1976 |
| Lori's Columbine | Aquilegia loriae | Resolved Taxon | Wherever found | |
| Los Angeles little pocket mouse | Perognathus longimembris brevinasus | Species of Concern | Wherever found | |
| Los Angeles sunflower | Helianthus nuttallii parishii | Species of Concern | Wherever found | |
| Los Olmos tiger beetle | Cicindela nevadica olmosa | Species of Concern | Wherever found | |
| Los Pinitos Dodder | Cuscuta dentatasquamata | Resolved Taxon | Wherever found | |
| Lost Creek wild buckwheat | Eriogonum mitophyllum | Resolved Taxon | Wherever found | |
| Lost ethmiid moth | Ethmia monachella | Species of Concern | Wherever found | |
| Lost Hills saltbush | Atriplex vallicola | Species of Concern | Wherever found | |
| Lost Nantahala Cave spider | Nesticus cooperi | Species of Concern | Wherever found | |
| Lost River sucker | Deltistes luxatus | Endangered | Wherever found | 07-18-1988 |
| Lotis blue butterfly | Lycaeides argyrognomon lotis | Endangered | Wherever found | 06-08-1976 |
| Louie's pocket gopher | Thomomys mazama louiei | Resolved Taxon | Wherever found | |
| Louisiana black bear | Ursus americanus luteolus | Recovery | Wherever found | 01-07-1992 |
| Louisiana blue-star | Amsonia ludoviciana | Resolved Taxon | Wherever found | |
| Louisiana Eye silkmoth | Automeris louisiana | Status Undefined | Wherever found | |
| Louisiana Fatmucket | Lampsilis hydiana | Not Listed | | |
| Louisiana pearlshell | Margaritifera hembeli | Threatened | Wherever found | 02-05-1988 |
| Louisiana Pigtoe | Pleurobema riddellii | Proposed Threatened | Wherever found | |
| Louisiana pinesnake | Pituophis ruthveni | Threatened | Wherever found | 05-07-2018 |
| Louisiana prairie vole | Microtus ochrogaster ludovicianus | Resolved Taxon | Wherever found | |
| Louisiana quillwort | Isoetes louisianensis | Endangered | Wherever found | 10-28-1992 |
| Louisiana Slimy Salamander | Plethodon kisatchie | Species of Concern | Wherever found | |
| Louisiana Waterthrush | Parkesia motacilla | Species of Concern | Wherever found | |
| Louisville Cave beetle | Pseudanophthalmus troglodytes | Resolved Taxon | Wherever found | |
| Louisville crayfish | Orconectes jeffersoni | Species of Concern | Wherever found | |
| loulu | Pritchardia aylmer-robinsonii | Endangered | Wherever found | 08-07-1996 |
| loulu | Pritchardia bakeri | Endangered | Wherever found | 10-31-2016 |
| loulu | Pritchardia glabrata | Resolved Taxon | Wherever found | |
| loulu | Pritchardia hardyi | Endangered | Wherever found | 05-13-2010 |
| loulu | Pritchardia kaalae | Endangered | Wherever found | 10-10-1996 |
| loulu | Pritchardia lanaiensis | Resolved Taxon | Wherever found | |
| loulu | Pritchardia lanigera | Endangered | Wherever found | 11-29-2013 |
| loulu | Pritchardia maideniana | Endangered | Wherever found | 03-04-1994 |
| loulu | Pritchardia martii | Resolved Taxon | Wherever found | |
| loulu | Pritchardia minor | Resolved Taxon | Wherever found | |
| loulu | Pritchardia munroi | Endangered | Wherever found | 10-08-1992 |
| loulu | Pritchardia napaliensis | Endangered | Wherever found | 10-10-1996 |
| loulu | Pritchardia remota | Endangered | Wherever found | 08-21-1996 |
| loulu | Pritchardia schattaueri | Endangered | Wherever found | 10-10-1996 |
| loulu | Pritchardia viscosa | Endangered | Wherever found | 10-10-1996 |
| Loulu | Pritchardia affinis | Resolved Taxon | | |
| loulu lelo | Pritchardia hillebrandii | Resolved Taxon | Wherever found | |
| Lovegrass noctuid moth | Hypena plagiota | Resolved Taxon | Wherever found | |
| Low beardtongue | Penstemon humilis var. humilis | Resolved Taxon | Wherever found | |
| Low beardtongue | Penstemon nanus | Species of Concern | Wherever found | |
| Low bush monkeyflower | Diplacus aridus | Resolved Taxon | Wherever found | |
| Lower Keys cotton rat | Sigmodon hispidus exsputus | Resolved Taxon | Wherever found | |
| Lower Keys marsh rabbit | Sylvilagus palustris hefneri | Endangered | Wherever found | 06-21-1990 |
| Lowland anoa | Bubalus depressicornis | Endangered | Wherever found | 06-02-1970 |
| Lowland leopard (=San Felipe leopard) frog | Rana yavapaiensis | Species of Concern | Wherever found | |
| Lucifer Hummingbird | Calothorax lucifer | Species of Concern | Wherever found | |
| Lucy's warbler | Vermivora luciae | Status Undefined | Wherever found | |
| Lum's micro-blind harvestman | Microcina lumi | Species of Concern | Wherever found | |
| Lupine blue butterfly | Plebejus lupini texanus | Resolved Taxon | Wherever found | |
| Lupine, San Mateo tre | Lupinus arboreus eximius | Species of Concern | Wherever found | |
| Luzon peacock swallowtail butterfly | Papilio chikae | Endangered | Wherever found | 01-14-1993 |
| Lynn's clubtail | Gomphus lynnae | Species of Concern | Wherever found | |
| Lyon's pentachaeta | Pentachaeta lyonii | Endangered | Wherever found | 01-29-1997 |
| Lyrate bladderpod | Lesquerella lyrata | Threatened | Wherever found | 09-28-1990 |
| Lyrate mountainsnail | Oreohelix haydeni haydeni | Species of Concern | Wherever found | |
| Lyrate rocksnail | Leptoxis lirata | Resolved Taxon | Wherever found | |
| macaroni penguin | Eudyptes chrysolophus | Species of Concern | Campbell Plateau portion of New Zealand/Australia population | |
| MacDougal''s Yellowtops | Flaveria mcdougalii | Resolved Taxon | Wherever found | |
| MacFarlane's four-o'clock | Mirabilis macfarlanei | Threatened | Wherever found | 11-29-1979 |
| MacGillivray's Seaside Sparrow | Ammospiza maritima macgillivraii | Resolved Taxon | Wherever found | |
| Macgillivray's warbler | oporornis tolmiei | Species of Concern | Wherever found | |
| MacKenzie's cave amphipod | Stygobromus mackenziei | Resolved Taxon | Wherever found | |
| MacNeill sooty wing skipper | Hesperopsis gracielae | Species of Concern | Wherever found | |
| Macoun's Cinquefoil | Potentilla macounii | Resolved Taxon | Wherever found | |
| Maculated manfreda skipper | Stallingsia maculosus | Resolved Taxon | Wherever found | |
| Madagascar pochard | Aythya innotata | Endangered | Wherever found | 01-12-1995 |
| Madagascar radiated tortoise | Geochelone radiata | Endangered | Wherever found | 06-02-1970 |
| Madagascar red owl | Tyto soumagnei | Endangered | Wherever found | 09-28-1990 |
| Madagascar sea eagle | Haliaeetus vociferoides | Endangered | Wherever found | 01-12-1995 |
| Madagascar serpent eagle | Eutriorchis astur | Endangered | Wherever found | 01-12-1995 |
| Madera Talussnail | Sonorella clappi | Resolved Taxon | Wherever found | |
| Madison Cave isopod | Antrolana lira | Threatened | Wherever found | 10-04-1982 |
| Madla Cave Meshweaver | Cicurina madla | Endangered | Wherever found | 12-26-2000 |
| Magazine Mountain mold beetle | Arianops sandersoni | Species of Concern | Wherever found | |
| Magazine Mountain shagreen | Inflectarius magazinensis | Recovery | Wherever found | 04-17-1989 |
| Magdalena Mountainsnail | Oreohelix magdalenae | Resolved Taxon | Wherever found | |
| Magenta petrel | Pterodroma magentae | Endangered | Wherever found | 09-14-2009 |
| Magnificent Frigatebird | Fregata magnificens | Species of Concern | Wherever found | |
| Magnificent ramshorn | Planorbella magnifica | Endangered | Wherever found | 09-18-2023 |
| Maguire daisy | Erigeron maguirei | Recovery | Wherever found | 09-05-1985 |
| Maguire primrose | Primula maguirei | Threatened | Wherever found | 08-21-1985 |
| Mahoe | Alectryon macrococcus | Endangered | Wherever found | 05-15-1992 |
| Maiden rocksnail | Leptoxis formosa | Resolved Taxon | Wherever found | |
| Maiden Spring cave beetle | Pseudanophthalmus virginicus | Not Listed | Wherever found | |
| Makah copper butterfly | Tharsalea mariposa makah | Status Undefined | | |
| Makou | Botrychium subbifoliatum | Species of Concern | Wherever found | |
| Makou | Brachionidium ciliolatum | Species of Concern | Wherever found | |
| Makou | Peucedanum sandwicense | Threatened | Wherever found | 02-25-1994 |
| Makou | Ranunculus hawaiensis | Endangered | Wherever found | 10-31-2016 |
| Makou | Ranunculus mauiensis | Endangered | Wherever found | 10-31-2016 |
| Malabar large-spotted civet | Viverra civettina (=megaspila c.) | Endangered | Wherever found | 07-27-1979 |
| Maleo megapode | Macrocephalon maleo | Endangered | Wherever found | 06-02-1970 |
| Malheur Cave amphipod | Stygobromus hubbsi | Resolved Taxon | Wherever found | |
| Malheur mottled sculpin | Cottus bairdii | Species of Concern | Wherever found | |
| Malheur pseudoscorpion | Apochthonius malheuri | Species of Concern | Wherever found | |
| Malheur Sculpin | Cottus bendirei | Not Listed | | |
| Malheur Valley fiddleneck | Amsinckia carinata | Resolved Taxon | Wherever found | |
| Malheur wire-lettuce | Stephanomeria malheurensis | Endangered | Wherever found | 11-10-1982 |
| Mallard | Anas platyrhynchos | Status Undefined | Wherever found | |
| Malone Mountains Moonpod | Selinocarpus maloneanus | Resolved Taxon | Wherever found | |
| Mammoth Spring crayfish | Faxonius marchandi | Resolved Taxon | Wherever found | |
| Manantial Roundnose Minnow | Dionda argentosa | Not Listed | | |
| Mancos columbine | Aquilegia micrantha mancosana | Resolved Taxon | Wherever found | |
| Mancos milk-vetch | Astragalus humillimus | Endangered | Wherever found | 06-27-1985 |
| Mandrill | Mandrillus (=Papio) sphinx | Endangered | Wherever found | 10-19-1976 |
| Maned wolf | Chrysocyon brachyurus | Endangered | Wherever found | 12-02-1970 |
| Manena | Melicope cinerea | Resolved Taxon | Wherever found | |
| Mangrove clapper rail | Rallus longirostris insularum | Species of Concern | Wherever found | |
| Mangrove Cuckoo | Coccyzus minor | Species of Concern | Wherever found | |
| Manhart's sedge | Carex manhartii | Species of Concern | Wherever found | |
| Manitou cavesnail | Antrorbis breweri | Under Review | Wherever found | |
| Mann's bluegrass | Poa mannii | Endangered | Wherever found | 11-10-1994 |
| Manoa bidens | Bidens coarctata | Resolved Taxon | Wherever found | |
| Mantled howler monkey | Alouatta palliata | Endangered | Wherever found | 06-14-1976 |
| Manus Island tree snail | Papustyla pulcherrima | Endangered | Wherever found | 06-02-1970 |
| Manx Shearwater | Puffinus puffinus | Species of Concern | Wherever found | |
| Many-colored Fruit-Dove | Ptilinopus perousii perousii | Resolved Taxon | Wherever found | |
| Many-flowered navarretia | Navarretia leucocephala ssp. plieantha | Endangered | Wherever found | 06-18-1997 |
| Many-flowered nehe | Lipochaeta profusa profusa | Resolved Taxon | Wherever found | |
| Many-flowered unicorn plant | Proboscidea spicata | Resolved Taxon | Wherever found | |
| Manyflower grasspink | Calopogon multiflorus | Status Undefined | Wherever found | |
| Many-Lined Salamander | Stereochilus marginatus | Not Listed | | |
| Many-stemmed liveforever | Dudleya multicaulis | Species of Concern | Wherever found | |
| Ma`ohi`ohi | Stenogyne rugosa subulata | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea amplexicaulis | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea apokremnos | Endangered | Wherever found | 09-30-1991 |
| Ma`oli`oli | Schiedea globosa foliosior | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea globosa globosa | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea globosa graminifolia | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea hawaiiensis | Endangered | Wherever found | 11-29-2013 |
| Ma`oli`oli | Schiedea kealiae | Endangered | Wherever found | 10-10-1996 |
| Ma`oli`oli | Schiedea ligustrina nematopoda | Resolved Taxon | Wherever found | |
| Ma`oli`oli | Schiedea pubescens | Endangered | Wherever found | 10-31-2016 |
| Ma`oloa | Neraudia melastomifolia | Resolved Taxon | Wherever found | |
| Mao (= maomao) (honeyeater) | Gymnomyza samoensis | Endangered | Wherever found | 10-24-2016 |
| Mapele | Cyrtandra cyaneoides | Endangered | Wherever found | 10-10-1996 |
| Maple Canyon Woodlandsnail | Ashmunella todseni | Resolved Taxon | Wherever found | |
| Mapleleaf | Quadrula quadrula | Not Listed | | |
| Maple-leaf oak | Quercus shumardii acerifolia | Species of Concern | Wherever found | |
| Mapleleaf Oak | Quercus acerifolia | Resolved Taxon | Wherever found | |
| Maraca | Canna pertusa | Species of Concern | Wherever found | |
| Maravillas milkwort | Polygala maravillasensis | Species of Concern | Wherever found | |
| Maravillas red shiner | Cyprinella lutrensis blairi | Resolved Taxon | Wherever found | |
| Marble Canyon kangaroo rat | Dipodomys microps leucotis | Species of Concern | Wherever found | |
| Marble Canyon Spurge | Euphorbia aaronrossii | Not Listed | | |
| Marbled cat | Pardofelis (=Felis) marmorata | Endangered | Wherever found | 06-14-1976 |
| Marbled disc | Discus marmorensis | Species of Concern | Wherever found | |
| Marbled Godwit | Limosa fedoa | Species of Concern | Wherever found | |
| Marbled Murrelet | Brachyramphus marmoratus | Species of Concern | Entire, except U.S.A. (CA, OR, WA) | |
| Marbled Murrelet | Brachyramphus marmoratus | Threatened | U.S.A. (CA, OR, WA) | 10-01-1992 |
| Marbled Sculpin | Cottus klamathensis | Not Listed | | |
| Marbled underwing moth | Catocala marmorata | Resolved Taxon | Wherever found | |
| Marble Mountain catchfly | Silene marmorensis | Species of Concern | Wherever found | |
| Marble-seeded, few-spined prickly-pear | Opuntia engelmannii flexospina | Species of Concern | Wherever found | |
| Marcescent dudleya | Dudleya cymosa ssp. marcescens | Threatened | Wherever found | 01-29-1997 |
| Mardon skipper | Polites mardon | Resolved Taxon | Wherever found | |
| Margaretta's hermit | Phaethornis malaris margarettae | Endangered | Wherever found | 01-27-2011 |
| Margarita River skimmer | Macromia margarita | Under Review | Wherever found | |
| Margay | Leopardus (=Felis) wiedii | Endangered | Wherever found | 03-30-1972 |
| Margined sculpin | Cottus marginatus | Species of Concern | Wherever found | |
| Maria Island ground lizard | Cnemidophorus vanzoi | Endangered | Wherever found | 09-30-1991 |
| Maria Island snake | Liophus ornatus | Endangered | Wherever found | 09-30-1991 |
| Mariana (=aga) Crow | Corvus kubaryi | Endangered | Wherever found | 08-27-1984 |
| Mariana common moorhen (pulattat) | Gallinula chloropus guami | Endangered | Wherever found | 08-27-1984 |
| Mariana eight-spot butterfly | Hypolimnas octocula marianensis | Endangered | Wherever found | 11-02-2015 |
| Mariana fruit Bat (=Mariana flying fox) | Pteropus mariannus mariannus | Threatened | Wherever found | 08-27-1984 |
| Mariana Fruit-Dove | Ptilinopus roseicapilla | Resolved Taxon | Wherever found | |
| Mariana Kingfisher | Todiramphus albicilla | Species of Concern | | |
| Mariana mallard | Anas oustaleti | Extinction | Wherever found | 12-08-1977 |
| Marianas euploea butterfly | Euploea eleutho | Resolved Taxon | Wherever found | |
| Mariana swiftlet | Aerodramus bartschi | Endangered | Wherever found | 08-27-1984 |
| Mariana wandering butterfly | Vagrans egistina | Endangered | Wherever found | 11-02-2015 |
| Maricao cimarron | Byrsonima lucida | Species of Concern | Wherever found | |
| Maricao cimarron | Byrsonima spicata | Species of Concern | Wherever found | |
| Maricopa tiger beetle | Cicindela oregona maricopa | Species of Concern | Wherever found | |
| Marin bentgrass | Agrostis blasdalei marinensis | Resolved Taxon | Wherever found | |
| Marin blind harvestman | Calicina diminua | Status Undefined | Wherever found | |
| Marin checkermallow | Sidalcea hickmanii viridis | Species of Concern | Wherever found | |
| Marin dwarf-flax | Hesperolinon congestum | Threatened | Wherever found | 02-03-1995 |
| Marin elfin | Incisalia mossii ssp. | Species of Concern | Marin | |
| Marine otter | Lontra (=Lutra) felina | Endangered | Wherever found | 06-14-1976 |
| Marin knotweed | Polygonum marinense | Species of Concern | Wherever found | |
| Marin manzanita | Arctostaphylos virgata | Resolved Taxon | Wherever found | |
| Mariposa clarkia | Clarkia biloba australis | Resolved Taxon | Wherever found | |
| Mariposa lily | Calochortus simulans | Resolved Taxon | Wherever found | |
| Mariposa lily | Calochortus venustus sanguineus | Resolved Taxon | Wherever found | |
| Mariposa lupine | Lupinus citrinus deflexus | Resolved Taxon | Wherever found | |
| Mariposa pussypaws | Calyptridium pulchellum | Threatened | Wherever found | 10-14-1998 |
| Maritime california-lilac | Ceanothus maritimus | Species of Concern | Wherever found | |
| Maritime Texas pocket gopher | Geomys personatus maritimus | Species of Concern | Wherever found | |
| Markhor | Capra falconeri | Under Review | Wherever found | |
| Marquesan monarch | Pomarea mendozae mira | Resolved Taxon | Wherever found | |
| Marquesas pigeon | Ducula galeata | Endangered | Wherever found | 09-12-2011 |
| Marron bacora | Solanum conocarpum | Endangered | | 07-18-2022 |
| Marron's San Carlos riffle beetle | Huleechius marroni carolus | Species of Concern | Wherever found | |
| Marsh deer | Blastocerus dichotomus | Endangered | Wherever found | 06-02-1970 |
| Marsh Sandwort | Arenaria paludicola | Endangered | Wherever found | 08-03-1993 |
| Marsh Slug | Deroceras heterura | Resolved Taxon | Wherever found | |
| Marsh valerian | Valeriana uliginosa | Resolved Taxon | Wherever found | |
| Martha's Vineyard short-tailed shrew | Blarina brevicauda aloga | Resolved Taxon | Wherever found | |
| Martha's Vineyard white-footed mouse | Peromyscus leucopus fusus | Resolved Taxon | Wherever found | |
| Martin cave beetle | Pseudanophthalmus pusillus | Species of Concern | Wherever found | |
| Martinique trembler (thrasher) | Cinclocerthia ruficauda gutturalis | Endangered | Wherever found | 06-02-1970 |
| Marungu sunbird | Nectarinia prigoginei | Endangered | Wherever found | 01-12-1995 |
| Mary Alice's smallheaded fly | Eulonchus marialiciae | Species of Concern | Wherever found | |
| Maryland bur-marigold | Bidens bidentoides mariana | Species of Concern | Wherever found | |
| Maryland cave beetle | Pseudanopthalmus sp. | Species of Concern | Wherever found | |
| Maryland darter | Etheostoma sellare | Endangered | Wherever found | 03-11-1967 |
| Maryland glyph | Glyphyalinia raderi | Species of Concern | Wherever found | |
| Mary's bluet | Hedyotis butterwickiae | Resolved Taxon | Wherever found | |
| Marysville California kangaroo rat | Dipodomys californicus eximius | Species of Concern | Wherever found | |
| Mascarene black petrel | Pterodroma aterrima | Endangered | Wherever found | 01-12-1995 |
| Masked bobwhite (quail) | Colinus virginianus ridgwayi | Endangered | Wherever found | 03-11-1967 |
| Masked Booby | Sula dactylatra dactylatra | Species of Concern | Wherever found | |
| Masked Duck | Nomonyx dominicus | Species of Concern | Wherever found | |
| Masked duskysnail | Lyogyrus spb | Resolved Taxon | Wherever found | |
| Masonic Mountain jewelflower | Streptanthus oliganthus | Species of Concern | Wherever found | |
| Mason's lilaeopsis | Lilaeopsis masonii | Species of Concern | Wherever found | |
| Mason's sky-pilot | Polemonium chartaceum | Resolved Taxon | Wherever found | |
| Mat-forming quillwort | Isoetes tegetiformans | Endangered | Wherever found | 02-05-1988 |
| Mat-forming water-hyssop | Bacopa innominata | Resolved Taxon | Wherever found | |
| Mathias' coyote-thistle | Eryngium mathiasiae | Resolved Taxon | Wherever found | |
| Mathis spiderling | Boerhavia mathisiana | Species of Concern | Wherever found | |
| Mat leastdaisy | Chaetopappa hersheyi | Species of Concern | Wherever found | |
| Matthew's wild-buckwheat | Eriogonum corymbosum matthewsae | Resolved Taxon | Wherever found | |
| Mattoni''s blue | Euphilotes pallescens mattonii | Resolved Taxon | Wherever found | |
| Mattoni's blue | Euphilotes rita mattoni | Species of Concern | Wherever found | |
| Maui `akala long-horned beetle | Plagithmysus rubi | Species of Concern | Wherever found | |
| Maui akepa | Loxops ochraceus | Extinction | Wherever found | 10-13-1970 |
| Maui alani long-horned beetle | Plagithmysus alani | Species of Concern | Wherever found | |
| Maui 'Alauahio | Paroreomyza montana | Species of Concern | Wherever found | |
| Maui banana omoides moth | Omoides musicola | Species of Concern | Wherever found | |
| Maui dolphin | Cephalorhynchus hectori maui | Endangered | | 10-19-2017 |
| Maui dubautia long-horned beetle | Plagithmysus dubautianus | Species of Concern | Wherever found | |
| Maui forest long-horned beetle | Plagithmysus sylvai | Species of Concern | Wherever found | |
| Maui koa long-horned beetle | Plagithmysus koae | Species of Concern | Wherever found | |
| Maui love grass | Eragrostis mauiensis | Resolved Taxon | Wherever found | |
| Maui mamaki long-horned beetle | Plagithmysus pipturicola | Species of Concern | Wherever found | |
| Maui nukupuu | Hemignathus affinis | Extinction | Wherever found | 10-13-1970 |
| Maui parrotbill (Kiwikiu) | Pseudonestor xanthophrys | Endangered | Wherever found | 03-11-1967 |
| Maui reedgrass | Calamagrostis expansa | Endangered | Wherever found | 10-31-2016 |
| Maui remya | Remya mauiensis | Endangered | Wherever found | 01-14-1991 |
| Maui similar long-horned beetle | Plagithmysus simillimus | Species of Concern | Wherever found | |
| Maui speculifer long-horned beetle | Plagithmysus speculifer | Species of Concern | Wherever found | |
| Maui tree snail | Partulina anceyana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina carnicolor | Species of Concern | Wherever found | |
| Maui tree snail | Partulina crocea | Species of Concern | Wherever found | |
| Maui tree snail | Partulina dolei | Species of Concern | Wherever found | |
| Maui tree snail | Partulina fusoidea | Species of Concern | Wherever found | |
| Maui tree snail | Partulina germana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina gouldii | Species of Concern | Wherever found | |
| Maui tree snail | Partulina grisea | Species of Concern | Wherever found | |
| Maui tree snail | Partulina induta | Species of Concern | Wherever found | |
| Maui tree snail | Partulina kaaeana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina lemmoni | Species of Concern | Wherever found | |
| Maui tree snail | Partulina marmorata | Species of Concern | Wherever found | |
| Maui tree snail | Partulina mutabilis | Species of Concern | Wherever found | |
| Maui tree snail | Partulina natti | Species of Concern | Wherever found | |
| Maui tree snail | Partulina nivea | Species of Concern | Wherever found | |
| Maui tree snail | Partulina perdix | Species of Concern | Wherever found | |
| Maui tree snail | Partulina plumbea | Species of Concern | Wherever found | |
| Maui tree snail | Partulina porcellana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina radiata | Species of Concern | Wherever found | |
| Maui tree snail | Partulina splendida | Species of Concern | Wherever found | |
| Maui tree snail | Partulina tapaniana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina terebra | Species of Concern | Wherever found | |
| Maui tree snail | Partulina thaanumiana | Species of Concern | Wherever found | |
| Maui tree snail | Partulina ustulata | Species of Concern | Wherever found | |
| Maui tree snail | Partulina winniei | Species of Concern | Wherever found | |
| Maui wide-necked long-horned beetle | Plagithmysus laticollis | Species of Concern | Wherever found | |
| Maui yellow-faced bee | Nesoprosopis mauiensis | Resolved Taxon | Wherever found | |
| Mauna Loa (=Ka'u) silversword | Argyroxiphium kauense | Endangered | Wherever found | 04-07-1993 |
| Mauna Loa metrargan seed bug | Metrarga obscura | Species of Concern | Wherever found | |
| Maunalua bidens | Bidens graciloides | Resolved Taxon | Wherever found | |
| Maureen's gymnocthebius minute moss beetle | Gymnocthebius maureenae | Species of Concern | Wherever found | |
| Maureen's hydraenan minute moss beetle | Hydraena maureenae | Species of Concern | Wherever found | |
| Mauritius cuckoo-shrike | Coquus typicus | Endangered | Wherever found | 06-02-1970 |
| Mauritius fody | Foudia rubra | Endangered | Wherever found | 01-12-1995 |
| Mauritius kestrel | Falco punctatus | Endangered | Wherever found | 06-02-1970 |
| Mauritius olivaceous Bulbul | Hypsipetes borbonicus olivaceus | Endangered | Wherever found | 06-02-1970 |
| Mauritius parakeet | Psittacula echo | Endangered | Wherever found | 06-02-1970 |
| Mayaguana iguana | Cyclura carinata bartschi | Threatened | Wherever found | 06-22-1983 |
| Mayfly | Fallceon eatoni | Resolved Taxon | Wherever found | |
| McCart's whitlow-wort | Paronychia maccartii | Resolved Taxon | Wherever found | |
| McCloud R. redband trout | Oncorhynchus mykiss ssp. | Resolved Taxon | McCloud R. | |
| McCown's Longspur | Calcarius mccownii | Species of Concern | Wherever found | |
| McDonald''s rock-cress | Arabis mcdonaldiana | Endangered | Wherever found | 09-29-1978 |
| McKay's Bunting | Plectrophenax hyperboreus | Status Undefined | Wherever found | |
| Mckittrick pennyroyal | Hedeoma apiculatum | Original Data in Error - New Information Discovered | Wherever found | 07-13-1982 |
| McKittrick snowberry | Symphoricarpos guadalupensis | Species of Concern | Wherever found | |
| Mckittrick Woodlandsnail | Ashmunella edithae | Resolved Taxon | Wherever found | |
| McNeill's deer | Cervus elaphus macneilii | Endangered | Wherever found | 06-02-1970 |
| Meadow checkermallow | Sidalcea campestris | Resolved Taxon | Wherever found | |
| Meadow joint-vetch | Aeschynomene pratensis | Under Review | Wherever found | |
| Meadow pussytoes | Antennaria arcuata | Species of Concern | Wherever found | |
| Meadow Valley Wash desert sucker | Catostomus clarkii | Resolved Taxon | Meadow Valley | |
| Meadow Valley Wash speckled dace | Rhinichthys osculus ssp. | Resolved Taxon | Meadow Valley | |
| Mead's milkweed | Asclepias meadii | Threatened | Wherever found | 09-01-1988 |
| Mearns' southern pocket gopher | Thomomys umbrinus mearnsi | Species of Concern | Wherever found | |
| Mecca aster | Xylorhiza cognata | Species of Concern | Wherever found | |
| Median-gland Nevada springsnail | Pyrgulopsis pisteri | Resolved Taxon | Wherever found | |
| Mediterranean monk seal | Monachus monachus | Endangered | Wherever found | 06-02-1970 |
| Mehamehame | Flueggea neowawraea | Endangered | Wherever found | 11-10-1994 |
| Melanothrix yellow-faced bee | Nesoprosopis melanothrix | Resolved Taxon | Wherever found | |
| Melones harvestman | Banksula melones | Status Undefined | Wherever found | |
| Meltwater lednian stonefly | Lednia tumana | Threatened | Wherever found | 12-23-2019 |
| Mendocino bush-mallow | Malacothamnus mendocinensis | Species of Concern | Wherever found | |
| Mendocino coast paintbrush | Castilleja mendocinensis | Species of Concern | Wherever found | |
| Mendocino cypress | Cupressus goveniana pigmaea | Species of Concern | Wherever found | |
| Mendocino gentian | Gentiana setigera | Species of Concern | Wherever found | |
| Menzies' anacolia moss | anacolia menziesii | Species of Concern | Wherever found | |
| Menzies' wallflower | Erysimum menziesii | Endangered | Wherever found | 06-22-1992 |
| Meramac River vertigo | Vertigo meramecensis | Species of Concern | Wherever found | |
| Merced Canyon shoulderband | Helminthoglypta allynsmithi | Species of Concern | Wherever found | |
| Merced clarkia | Clarkia lingulata | Resolved Taxon | Wherever found | |
| Merced kangaroo rat | Dipodomys heermanni dixoni | Species of Concern | Wherever found | |
| Merced monardella | Monardella leucocephala | Species of Concern | Wherever found | |
| Merced phacelia | Phacelia ciliata opaca | Species of Concern | Wherever found | |
| Meridion blackwater mayfly | Pseudirion meridionalis | Resolved Taxon | Wherever found | |
| Meridith cave beetle | Pseudanophthalmus sidus | Species of Concern | Wherever found | |
| Merlin | falco columbarius | Species of Concern | Wherever found | |
| Merriam's Montezuma quail | Cyrtonyx montezumae merriami | Endangered | Wherever found | 06-14-1976 |
| Mer Rouge pocket gopher | Geomys bursarius breviceps | Resolved Taxon | Wherever found | |
| Mesa Verde cactus | Sclerocactus mesae-verdae | Threatened | Wherever found | 11-29-1979 |
| Mesa Verde stickleaf | Hackelia gracilenta | Resolved Taxon | Wherever found | |
| Mescalero milkwort | Polygala rimulicola mescalerorum | Species of Concern | Wherever found | |
| Metcalf Canyon jewelflower | Streptanthus albidus ssp. albidus | Endangered | Wherever found | 02-03-1995 |
| Metcalf Holospira | Holospira metcalfi | Resolved Taxon | Wherever found | |
| Mexicali Lubber grasshopper | Spaniacris deserticola | Resolved Taxon | Wherever found | |
| Mexican blindcat (catfish) | Prietella phreatophila | Endangered | Wherever found | 06-02-1970 |
| Mexican bobcat | Lynx (=Felis) rufus escuinapae | Endangered | Wherever found | 06-14-1976 |
| Mexican Chickadee | Poecile sclateri | Species of Concern | | |
| Mexican duck | Anas diazi | Original Data in Error - Taxonomic Revision | U.S. only | 03-11-1967 |
| Mexican fawnsfoot | Truncilla cognata | Proposed Endangered | Wherever found | |
| Mexican flannelbush | Fremontodendron mexicanum | Endangered | Wherever found | 10-13-1998 |
| Mexican Golden Trout | Oncorhynchus chrysogaster | Not Listed | | |
| Mexican hooded oriole | Icterus cucullatus cucullatus | Species of Concern | Wherever found | |
| Mexican long-nosed bat | Leptonycteris nivalis | Endangered | Wherever found | 09-30-1988 |
| Mexican long-tongued bat | Choeronycteris mexicana | Species of Concern | Wherever found | |
| Mexican prairie dog | Cynomys mexicanus | Endangered | Mexico | 06-02-1970 |
| Mexican Redhorse | Moxostoma austrinum | Not Listed | | |
| Mexican spotted owl | Strix occidentalis lucida | Threatened | Wherever found | 03-16-1993 |
| Mexican stoneroller | Campostoma ornatum | Species of Concern | Wherever found | |
| Mexican Tetra | Astyanax mexicanus | Not Listed | | |
| Mexican Whip-poor-will | Antrostomus arizonae | Species of Concern | | |
| Mexican wolf | Canis lupus baileyi | Endangered | Wherever found, except where included in an experimental population as set forth in 17.84(k) | 04-28-1976 |
| Mexican wolf | Canis lupus baileyi | Experimental Population, Non-Essential | U.S.A. (portions of AZ and NM)see 17.84(k) | 01-24-1998 |
| Meyrick's banana omoides moth | Omoides meyricki | Species of Concern | Wherever found | |
| Mhorr gazelle | Gazella dama mhorr | Endangered | Wherever found | 06-02-1970 |
| Miami Blue Butterfly | Cyclargus thomasi bethunebakeri | Endangered | Wherever found | 04-06-2012 |
| Miami Cave crayfish | Procambarus milleri | Proposed Threatened | Wherever found | |
| Miami palmetto | Sabal etonia | Resolved Taxon | Wherever found | |
| Miami roundhead scarab | Cyclocephala miamiensis | Species of Concern | Wherever found | |
| Miami tiger beetle | Cicindelidia floridana | Endangered | Wherever found | 11-04-2016 |
| Micco cottontail rabbit | Sylvilagus floridanus ammophilus | Resolved Taxon | Wherever found | |
| Micco hispid cotton rat | Sigmodon hispidus littoralis | Resolved Taxon | Wherever found | |
| Miccosukee gooseberry | Ribes echinellum | Threatened | | 07-18-1985 |
| Michaux's sumac | Rhus michauxii | Endangered | Wherever found | 09-28-1989 |
| Michigan bog grasshopper | Appalachia arcana | Species of Concern | Wherever found | |
| Michigan monkey-flower | Mimulus michiganensis | Endangered | Wherever found | 06-21-1990 |
| Micronesian megapode | Megapodius laperouse | Endangered | Wherever found | 06-02-1970 |
| Micronesian Myzomela | Myzomela rubratra | Species of Concern | Wherever found | |
| Micronesian starling | Aplonis opaca | Status Undefined | Wherever found | |
| Microreas agrotis noctuid moth | Agrotis microreas | Species of Concern | Wherever found | |
| Middlekauf's shieldback katydid | Idiostatus middlekaufi | Species of Concern | Wherever found | |
| Midget snaketail | Ophiogomphus howei | Species of Concern | Wherever found | |
| Midvalley Fairy Shrimp | Branchinecta mesovallensis | Resolved Taxon | Wherever found | |
| Midway agrotis noctuid moth | Agrotis fasciata | Resolved Taxon | Wherever found | |
| Migrant Loggerhead Shrike | Lanius ludovicianus migrans | Species of Concern | Wherever found | |
| Mikado pheasant | Syrmaticus mikado | Endangered | Wherever found | 06-02-1970 |
| (Miktoniscus) isopod | miktoniscus | Species of Concern | Wherever found | |
| Military macaw | Ara militaris | Endangered | Wherever found | 11-02-2015 |
| Milk Ranch Talussnail | Sonorella micromphala | Resolved Taxon | Wherever found | |
| Millboro leatherflower | Clematis viticaulis | Species of Concern | Wherever found | |
| Mill Creek Mountainsnail | Oreohelix howardi | Resolved Taxon | Wherever found | |
| Miller Lake lamprey | Entosphenus minimus | Resolved Taxon | Wherever found | |
| Millicoma dace | Rhinichthys cataractae | Species of Concern | Wherever found | |
| mimbres springsnail | pyrgulopsis species | Status Undefined | Wherever found | |
| Mimic cavesnail | Phreatodrobia imitata | Resolved Taxon | Wherever found | |
| Mimic crayfish | Distocambarus carlsoni | Under Review | Wherever found | |
| Mimic glass lizard | Ophisaurus mimicus | Species of Concern | Wherever found | |
| Mimic Shiner | Notropis volucellus | Not Listed | | |
| Mimic talussnail | Sonorella imitator | Resolved Taxon | Wherever found | |
| Mimic tryonia | Tryonia imitator | Species of Concern | Wherever found | |
| Mindoro imperial (=zone-tailed) pigeon | Ducula mindorensis | Endangered | Wherever found | 06-14-1976 |
| Mineral Creek mountainsnail | Oreohelix pilsbryi | Under Review | Wherever found | |
| Mineral King draba | Draba cruciata cruciata | Resolved Taxon | Wherever found | |
| Minnesota dwarf trout lily | Erythronium propullans | Endangered | Wherever found | 03-26-1986 |
| Minnesota Pleistocene succineid | Succinea sp. | Species of Concern | MN | |
| Minor cave amphipod | Crangonyx minor | Resolved Taxon | Wherever found | |
| Minute cave amphipod | Stygobromus parvus | Resolved Taxon | Wherever found | |
| Minute checkerspot butterfly | Poladryas minuta minuta | Resolved Taxon | Wherever found | |
| Minute helicoverpan noctuid moth | Helicoverpa minuta | Resolved Taxon | Wherever found | |
| Minute tryonia | Tryonia ericae | Resolved Taxon | Wherever found | |
| Mirey Ridge supercoil snail | Paravitrea clappi | Resolved Taxon | Wherever found | |
| Mission blue butterfly | Icaricia icarioides missionensis | Endangered | Wherever found | 06-08-1976 |
| Mission Canyon bluecup | Githopsis diffusa filicaulis | Species of Concern | Wherever found | |
| Mission Creek oregonian | Cryptomastix magnidentata | Species of Concern | Wherever found | |
| Mission Dolores campion | Silene verecunda verecunda | Resolved Taxon | Wherever found | |
| Mississippi diamondback terrapin | Malaclemys terrapin pileata | Species of Concern | Wherever found | |
| Mississippi flatwoods crayfish | Procambarus cometes | Not Listed | Wherever found | |
| Mississippi Green Water Snake | Nerodia cyclopion | Not Listed | | |
| Mississippi Kite | Ictinia mississippiensis | Species of Concern | Wherever found | |
| Mississippi redbelly turtle | Pseudemys concinna | Species of Concern | Wherever found | |
| Mississippi sandhill crane | Antigone canadensis pulla | Endangered | Wherever found | 06-04-1973 |
| Mississippi Silvery Minnow | Hybognathus nuchalis | Not Listed | | |
| Missouri bladderpod | Physaria filiformis | Threatened | Wherever found | 01-08-1987 |
| Missouri glyphopsyche caddisfly | Glyphopsyche missouri | Species of Concern | Wherever found | |
| Mitchell's satyr Butterfly | Neonympha mitchellii mitchellii | Endangered | Wherever found | 06-25-1991 |
| Miyako tango (=Toyko bitterling) | Tanakia tanago | Endangered | Wherever found | 06-02-1970 |
| Moapa dace | Moapa coriacea | Endangered | Wherever found | 03-11-1967 |
| Moapa pebblesnail | Pyrgulopsis avernalis | Resolved Taxon | Wherever found | |
| Moapa speckled dace | Rhinichthys osculus moapae | Resolved Taxon | Wherever found | |
| Moapa Valley pyrg | Pyrgulopsis carinifera | Resolved Taxon | Wherever found | |
| Moapa warm springs riffle beetle | Stenelmis moapa | Resolved Taxon | Wherever found | |
| Moapa White River springfish | Crenichthys baileyi moapae | Resolved Taxon | Wherever found | |
| Mobile Logperch | Percina kathae | Not Listed | | |
| Mock pennyroyal | Stachydeoma graveolens | Species of Concern | Wherever found | |
| Modest rock-cress | Arabis modesta | Resolved Taxon | Wherever found | |
| Modoc bedstraw | Galium glabrescens modocense | Resolved Taxon | Wherever found | |
| Modoc Sucker | Catostomus microps | Recovery | Wherever found | 06-11-1985 |
| Moestan blister beetle | Lytta moesta | Species of Concern | Wherever found | |
| Mogollon fleabane | Erigeron anchana | Species of Concern | Wherever found | |
| Mogollon hawkweed | hieracium fendleri | Species of Concern | Wherever found | |
| Mogollon thistle | Cirsium parryi mogollonicum | Species of Concern | Wherever found | |
| Mogollon woodlandsnail | Ashmunella mogollonensis | Resolved Taxon | Wherever found | |
| Mohave ground squirrel | Spermophilus mohavensis | Under Review | Wherever found | |
| Mohave shoulderband | Helminthoglypta greggi | Resolved Taxon | Wherever found | |
| Mohave tui chub | Gila bicolor ssp. mohavensis | Endangered | Wherever found | 10-13-1970 |
| Mohr's Barbara's buttons | Marshallia mohrii | Threatened | Wherever found | 09-07-1988 |
| Mojave Desert blister beetle | Lytta inseparata | Species of Concern | Wherever found | |
| Mojave fishhook cactus | Sclerocactus polyancistrus | Resolved Taxon | Wherever found | |
| Mojave fringe-toed Lizard | Uma scoparia | Status Undefined | Amargosa River population | |
| Mojave green rattlesnake | crotalus scutulatus ssp. scutulatus | Species of Concern | Wherever found | |
| Mojave indigo bush | Psorothamnus arborescens arborescens | Resolved Taxon | Wherever found | |
| Mojave monkey-flower | Mimulus mohavensis | Species of Concern | Wherever found | |
| Mojave Panicgrass | Panicum mohavense | Resolved Taxon | Wherever found | |
| Mojave poppy bee | Perdita meconis | Under Review | | |
| Mojave rabbitbrush longhorn beetle | Crossidius mojavensis mojavensis | Resolved Taxon | Wherever found | |
| Mojave river vole | Microtus californicus mohavensis | Species of Concern | Wherever found | |
| Mojave spineflower | Chorizanthe spinosa | Resolved Taxon | Wherever found | |
| Mojave tarweed | Hemizonia mohavensis | Species of Concern | Wherever found | |
| Molestan blister beetle | Lytta molesta | Species of Concern | Wherever found | |
| Molokai antlion | Distoleon perjerus | Species of Concern | Wherever found | |
| Molokai creeper | Paroreomyza flammea | Extinction | Wherever found | 10-13-1970 |
| Molokai cyanea | Cyanea solenocalyx | Resolved Taxon | Wherever found | |
| Molokai fractured long-horned beetle | Plagithmysus fractus | Species of Concern | Wherever found | |
| Molokai goosefoot | Chenopodium oahuense | Resolved Taxon | Wherever found | |
| Molokai megalagrion damselfly | Megalagrion molokaiense | Species of Concern | Wherever found | |
| Molokai `oloma`o | Myadestes lanaiensis rutha | Endangered | Wherever found | 10-13-1970 |
| Molokai rhyncogonus weevil | Rhyncogonus molokaiensis | Species of Concern | Wherever found | |
| Molokai sedge omoides moth | Omoides anastrepta | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina dwightii | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina mighelsiana | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina mucida | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina proxima | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina redfieldii | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina rufa | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina subpolita | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina tessellata | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina theodorei | Species of Concern | Wherever found | |
| Moloka`i tree snail | Partulina virgulata | Species of Concern | Wherever found | |
| Molokai yellow-faced bee | Nesoprosopis neglecta | Resolved Taxon | Wherever found | |
| Mona boa | Epicrates monensis monensis | Threatened | Wherever found | 03-06-1978 |
| Mona ground Iguana | Cyclura stejnegeri | Threatened | Wherever found | 03-06-1978 |
| Monarch butterfly | Danaus plexippus | Proposed Threatened | Wherever found | |
| Mona Skink | Spondylurus monae | Resolved Taxon | Wherever found | |
| Mongolian saiga (antelope) | Saiga tatarica mongolica | Endangered | Mongolia | 06-14-1976 |
| Monito gecko | Sphaerodactylus micropithecus | Recovery | Wherever found | 10-15-1982 |
| Monitor Valley speckled dace | Rhinichthys osculus ssp. | Species of Concern | Monitor Valley | |
| Monito Skink | Spondylurus monitoe | Resolved Taxon | Wherever found | |
| Monkeyface | Theliderma metanevra | Not Listed | | |
| Monkey Springs pupfish | Cyprinodon spp | Status Undefined | Wherever found | |
| Mono Basin skipper | Hesperia uncas giulianii | Resolved Taxon | Wherever found | |
| Mono buckwheat | Eriogonum ampullaceum | Resolved Taxon | Wherever found | |
| Mono checkerspot | Euphydryas editha monoensis | Species of Concern | Wherever found | |
| Monocolor yellow-faced bee | Nesoprosopis homeochroma | Resolved Taxon | Wherever found | |
| Mono Hot Springs evening-primrose | Camissonia sierrae alticola | Species of Concern | Wherever found | |
| Mono Lake brine shrimp | Artemia monica | Species of Concern | Wherever found | |
| Mono Lake hygrotus diving beetle | Hygrotus artus | Resolved Taxon | Wherever found | |
| Mono Lake lupine | Lupinus duranii | Species of Concern | Wherever found | |
| Mono manzanita | Arctostaphylos uva-ursi monoensis | Resolved Taxon | Wherever found | |
| Mono milk-vetch | Astragalus monoensis monoensis | Species of Concern | Wherever found | |
| Monomoy white-footed mouse | Peromyscus leucopus ammodytes | Species of Concern | Wherever found | |
| Mono phacelia | Phacelia monoensis | Species of Concern | Wherever found | |
| Montague tundra vole | Microtus oeconomus elymocetes | Species of Concern | Wherever found | |
| Montana Groundwater Amphipod | Stygobromus montanensis | Resolved Taxon | Wherever found | |
| Montana well Amphipod | Stygobromus puteanus | Resolved Taxon | Wherever found | |
| Montane Monkey-Faced Bat | Pteralopex pulchra | Under Review | Wherever found | |
| Montane peaclam | Pisidium ultramontanum | Resolved Taxon | Wherever found | |
| Montara manzanita | Arctostaphylos montaraensis | Species of Concern | Wherever found | |
| Monte Neva paintbrush | Castilleja salsuginosa | Species of Concern | Wherever found | |
| Monterey ceanothus | Ceanothus cuneatus rigidus | Species of Concern | Wherever found | |
| Monterey clover | Trifolium trichocalyx | Endangered | Wherever found | 08-12-1998 |
| Monterey cypress | Cupressus macrocarpa | Species of Concern | Wherever found | |
| Monterey Dunes scorpion | Pauroctonus maritimus | Species of Concern | Wherever found | |
| Monterey dusky-footed woodrat | Neotoma fuscipes luciana | Species of Concern | Wherever found | |
| Monterey gilia | Gilia tenuiflora ssp. arenaria | Endangered | Wherever found | 06-22-1992 |
| Monterey knotweed | Polygonum aviculare ssp. depressum | Resolved Taxon | Wherever found | |
| Monterey ornate shrew | Sorex ornatus salarius | Species of Concern | Wherever found | |
| Monterey pine | Pinus radiata | Species of Concern | Wherever found | |
| Monterey spineflower | Chorizanthe pungens var. pungens | Threatened | Wherever found | 02-04-1994 |
| Monterrey manzanita | Arctostaphylos montereyensis | Species of Concern | Wherever found | |
| Monte Verde golden toad | Bufo periglenes | Endangered | Wherever found | 06-14-1976 |
| Montezuma Well springsnail | Pyrgulopsis montezumensis | Resolved Taxon | Wherever found | |
| Mooneye | Hiodon tergisus | Not Listed | | |
| Moon pebblesnail | Somatogyrus obtusus | Species of Concern | Wherever found | |
| Moorea Polynesian warbler | Acrocephalus caffer longirostris | Resolved Taxon | Wherever found | |
| Moore Fairy Shrimp | Streptocephalus moorei | Resolved Taxon | Wherever found | |
| Moose | Alces alces | Not Listed | | |
| Morand's checkerspot | Euphydryas anicia morandi | Species of Concern | Wherever found | |
| Morand's checkerspot butterfly | Euphilotes anicia morandi | Resolved Taxon | Wherever found | |
| Morden's owlet | Otus ireneae | Endangered | Wherever found | 06-02-1970 |
| Morefield''s Leather Flower | Clematis morefieldii | Endangered | | 05-20-1992 |
| Morelet's crocodile | Crocodylus moreletii | Recovery | Wherever found | 06-02-1970 |
| Moreno currant | Ribes canthariforme | Species of Concern | Wherever found | |
| Morgan Creek Mountainsnail | Oreohelix swopei | Resolved Taxon | Wherever found | |
| Mormon White River Springfish | Crenichthys baileyi thermophilus | Species of Concern | Wherever found | |
| Moroccan gazelle | Gazella dorcas massaesyla | Endangered | Wherever found | 06-02-1970 |
| Morongo desertsnail | Eremarionta morongoana | Species of Concern | Wherever found | |
| Morrison bumblebee | Bombus morrisoni | Under Review | | |
| Morrison's blister beetle | Lytta morrisoni | Species of Concern | Wherever found | |
| Morrison's cave amphipod | Stygobromus morrisoni | Resolved Taxon | Wherever found | |
| Morrison's jewelflower | Streptanthus morrisonii morrisonii | Species of Concern | Wherever found | |
| Morro Bay blue butterfly | Icaricia icarioides moroensis | Species of Concern | Wherever found | |
| Morro Bay kangaroo rat | Dipodomys heermanni morroensis | Endangered | Wherever found | 10-13-1970 |
| Morro Bay Polyphyllan Scarab Beetle | Polyphylla morroensis | Under Review | | |
| Morro manzanita | Arctostaphylos morroensis | Threatened | Wherever found | 12-15-1994 |
| Morro shoulderband (=Banded dune) snail | Helminthoglypta walkeriana | Threatened | Wherever found | 12-15-1994 |
| Morse's Little Plain Brown sedge | Lepidostoma morsei | Not Listed | Wherever found | |
| Morse's net-spinning caddisfly | Cheumatopsyche morsei | Species of Concern | Wherever found | |
| Mosquin's clarkia | Clarkia mosquinii mosquinii | Species of Concern | Wherever found | |
| Moss gentian | Gentiana fremontii | Resolved Taxon | Wherever found | |
| Mossy elimia | Elimia troostiana | Species of Concern | Wherever found | |
| Most beautiful jewelflower | Streptanthus albidus peramoenus | Species of Concern | Wherever found | |
| Mother Lode yampah | Perideridia bacigalupii | Resolved Taxon | Wherever found | |
| Mottled coqui | Eleutherodactylus eneidae | Species of Concern | Wherever found | |
| Mottled Petrel | Pterodroma inexpectata | Species of Concern | | |
| Mountain anoa | Bubalus quarlesi | Endangered | Wherever found | 06-02-1970 |
| Mountain avens | Geum peckii | Resolved Taxon | Wherever found | |
| Mountain beaver | Aplodontia rufa californica | Species of Concern | Wherever found | |
| Mountain bittercress | Cardamine clematitis | Species of Concern | Wherever found | |
| Mountain Bluebird | Sialia currucoides | Species of Concern | Wherever found | |
| Mountain blue-eyed grass | Sisyrinchium sarmentosum | Resolved Taxon | Wherever found | |
| Mountain Brook Lamprey | Ichthyomyzon greeleyi | Not Listed | | |
| Mountain cave amphipod | Stygobromus montanus | Resolved Taxon | Wherever found | |
| Mountain Chickadee | Poecile gambeli | Species of Concern | Wherever found | |
| Mountain creekshell | Villosa vanuxemensis | Not Listed | | |
| Mountain (=Cuvier's) gazelle | Gazella cuvieri | Endangered | Wherever found | 06-02-1970 |
| Mountain golden heather | Hudsonia montana | Threatened | Wherever found | 10-20-1980 |
| Mountain Holospira | Holospira oritis | Resolved Taxon | Wherever found | |
| Mountain Labordia | Labordia hirtella | Resolved Taxon | Wherever found | |
| Mountain lady's-slipper | Cypripedium montanum | Resolved Taxon | Wherever found | |
| Mountain Madtom | Noturus eleutherus | Not Listed | | |
| Mountain Mullet | Agonostomus monticola | Not Listed | | |
| Mountain naupaka | Scaevola gaudichaudii | Resolved Taxon | Wherever found | |
| Mountainous Star Coral | Orbicella faveolata | Threatened | Wherever found | 11-13-2014 |
| Mountain phacelia | Phacelia orogenes | Resolved Taxon | Wherever found | |
| Mountain pimpernel | Taenidia montana | Resolved Taxon | Wherever found | |
| Mountain Plover | Charadrius montanus | Resolved Taxon | Wherever found | |
| Mountain Purple pitcherplant | Sarracenia purpurea var. montana | Under Review | Wherever found | |
| Mountain pygmy possum | Burramys parvus | Endangered | Wherever found | 12-02-1970 |
| Mountain quail | Oreortyx pictus | Resolved Taxon | Wherever found | |
| Mountain rattlesnake root | Prenanthes roanensis | Resolved Taxon | Wherever found | |
| Mountain Redbelly Dace | Chrosomus oreas | Not Listed | | |
| Mountain silverspot butterfly | Speyeria nokomis nitocris | Resolved Taxon | Wherever found | |
| Mountain-slope Thistle | Cirsium scapanolepis | Resolved Taxon | Wherever found | |
| Mountains Springs bush lupine | Lupinus excubitus medius | Species of Concern | Wherever found | |
| Mountain Sucker | Pantosteus platyrhynchus | Not Listed | | |
| Mountain sweet pitcher-plant | Sarracenia rubra ssp. jonesii | Endangered | Wherever found | 09-30-1988 |
| Mountain tapir | Tapirus pinchaque | Endangered | Wherever found | 06-02-1970 |
| mountain thaspium | Thaspium pinnatifidum | Species of Concern | Wherever found | |
| mountain whitefish | Prosopium williamsoni | Resolved Taxon | Big Lost River Distinct Population | |
| mountain whitefish | Prosopium williamsoni | Resolved Taxon | Wherever found | |
| Mountain yellow-legged frog | Rana muscosa | Endangered | U.S.A., northern California | 06-30-2014 |
| Mountain yellow-legged frog | Rana muscosa | Endangered | U.S.A., southern California | 07-02-2002 |
| Mountain yellow-legged frog | Rana muscosa | Not Listed | Wherever Found | |
| Mountain zebra | Equus zebra zebra | Endangered | Wherever found | 06-14-1976 |
| Mount Charleston blue butterfly | Icaricia (Plebejus) shasta charlestonensis | Endangered | Wherever found | 10-21-2013 |
| Mount Ellen pocket gopher | Thomomys umbrinus dissimilis | Species of Concern | Wherever found | |
| Mount Ellen Uinta chipmunk | Tamias umbrinus sedulus | Species of Concern | Wherever found | |
| Mount Graham red squirrel | Tamiasciurus fremonti grahamensis | Endangered | Wherever found | 06-03-1987 |
| Mount Hermon June beetle | Polyphylla barbata | Endangered | Wherever found | 01-24-1997 |
| Mount Lyell salamander | Hydromantes platycephalus | Species of Concern | Wherever found | |
| Mount Pinos sooty grouse | Dendragapus fuliginosus howardi | Resolved Taxon | | |
| Mount Riley Woodlandsnail | Ashmunella rileyensis | Resolved Taxon | Wherever found | |
| Mount Tamalpais jewelflower | Streptanthus glandulosus pulchellus | Resolved Taxon | Wherever found | |
| Mouse buckwheat | Eriogonum nudum murinum | Species of Concern | Wherever found | |
| Mouse-ear chickweed | Linum hudsonioides | Resolved Taxon | Wherever found | |
| Mouse-Eared Bats | Myotis sp. | Not Listed | | |
| Mouse-leaved dudleya | Dudleya abramsii murina | Resolved Taxon | Wherever found | |
| Mt. Diablo bird's-beak | Cordylanthus nidularius | Resolved Taxon | Wherever found | |
| Mt. Diablo jewelflower | Streptanthus hispidus | Species of Concern | Wherever found | |
| Mt. Diablo manzanita | Arctostaphylos auriculata | Resolved Taxon | Wherever found | |
| Mt. Diablo phacelia | Phacelia phacelioides | Species of Concern | Wherever found | |
| Mt. Eddy buckwheat | Eriogonum umbellatum humistratum | Resolved Taxon | Wherever found | |
| Mt. Eddy draba | Draba carnosula | Species of Concern | Wherever found | |
| Mt. Eke peperomia | Peperomia eekana | Resolved Taxon | Wherever found | |
| Mt. Gleason paintbrush | Castilleja gleasonii | Species of Concern | Wherever found | |
| Mt. Haleakala seed bug | Neseis haleakalae | Species of Concern | Wherever found | |
| Mt. Hamilton coreopsis | Coreopsis hamiltonii | Species of Concern | Wherever found | |
| Mt. Hamilton harebell | Campanula sharsmithiae | Species of Concern | Wherever found | |
| Mt. Hamilton jewelflower | Streptanthus callistus | Species of Concern | Wherever found | |
| Mt. Hamilton thistle | Cirsium fontinale campylon | Species of Concern | Wherever found | |
| Mt. Hood farulan caddisfly | Farula jewetti | Species of Concern | Wherever found | |
| Mt. Hood primitive brachycentrid caddisfly | Eobrachycentrus gelidae | Species of Concern | Wherever found | |
| Mt. Lassen smelowskia | Smelowskia ovalis congesta | Resolved Taxon | Wherever found | |
| Mt. Leconte moss | Leptothymenium sharpii | Species of Concern | Wherever found | |
| Mt. Lyell shrew | Sorex lyelli | Resolved Taxon | Wherever found | |
| Mt. Matafao different snail | Diastole matafaoi | Species of Concern | Wherever found | |
| Mt. Pinos larkspur | Delphinium parryi ssp. purpureum | Resolved Taxon | Wherever found | |
| Mt. Rainier white-tailed ptarmigan | Lagopus leucura rainierensis | Threatened | Wherever found | 08-02-2024 |
| Mt. Saint Helena morning-glory | Calystegia collina oxyphylla | Species of Concern | Wherever found | |
| Mt. Tamalpais thistle | Cirsium hydrophilum vaseyi | Species of Concern | Wherever found | |
| Mt. Tantalus short-wing fern planthopper | Nesorestias filicicola | Species of Concern | Wherever found | |
| Mt. Tantalus wingless thread bug | Nesidiolestes insularis | Species of Concern | Wherever found | |
| Mt. Tedoc linanthus | Linanthus nuttallii howellii | Species of Concern | Wherever found | |
| Mt. Trumbull beardtongue | Penstemon distans | Species of Concern | Wherever found | |
| Mt. Vision ceanothus | Ceanothus gloriosus porrectus | Species of Concern | Wherever found | |
| Mt. Whitney draba | Draba cruciata integrifolia | Resolved Taxon | Wherever found | |
| Mucket | Ortmanniana ligamentina | Not Listed | | |
| Mud Darter | Etheostoma asprigene | Not Listed | | |
| Muddy rocksnail | Lithasia salebrosa | Species of Concern | Wherever found | |
| Mud elimia | Elimia alabamensis | Not Listed | Wherever found | |
| Mud pebblesnail | Somatogyrus sargenti | Species of Concern | Wherever found | |
| Mudpuppy | Necturus maculosus | Not Listed | | |
| Mugger crocodile | Crocodylus palustris palustris | Endangered | Wherever found | 06-14-1976 |
| Muhlenberg''s smile | Rinodina chrysomelaena | Species of Concern | | |
| Muir's ala`a long-horned beetle | Plagithmysus muiri | Species of Concern | Wherever found | |
| Muir's raillardella | Carlquistia muirii | Resolved Taxon | Wherever found | |
| Mule deer | Odocoileus hemionus | Not Listed | | |
| Mulford's milk-vetch | Astragalus mulfordiae | Species of Concern | Wherever found | |
| Munro's nesotocus weevil | Nesotocus munroi | Species of Concern | Wherever found | |
| Munz cholla | Opuntia munzii | Species of Concern | Wherever found | |
| Munz's hedgehog cactus | Echinocereus engelmannii munzii | Species of Concern | Wherever found | |
| Munz's mariposa lily | Calochortus palmeri munzii | Species of Concern | Wherever found | |
| Munz's onion | Allium munzii | Endangered | Wherever found | 10-13-1998 |
| Munz''s sage | Salvia munzii | Not Listed | | |
| Murdock's evening primrose | Oenothera murdockii | Resolved Taxon | Wherever found | |
| Murphy's Petrel | Pterodroma ultima | Species of Concern | | |
| Murta | Marlierea sintenisii | Resolved Taxon | Wherever found | |
| Muscular sponge | Anheteromyia biceps | Resolved Taxon | Wherever found | |
| Music Hall Cave pseudoscorpion | Pseudogarypus orpheus | Species of Concern | Wherever found | |
| Musinea Ragwort | Senecio musiniensis | Resolved Taxon | Wherever found | |
| Musk deer | Moschus spp. (all species) | Endangered | Afghanistan, Bhutan, Burma, China (Tibet, Yunnan), India, Nepal, Pakistan, Sikkim | 06-14-1976 |
| Muskellunge | Esox masquinongy | Not Listed | | |
| Muskellunge | Esox masquinongy | Status Undefined | Tiger Muskellunge (x Esox lucius hybrid) | |
| Mussentuchit gilia | Gilia tenuis | Resolved Taxon | Wherever found | |
| Mutatan yellow-faced bee | Nesoprosopis mutata | Resolved Taxon | Wherever found | |
| Mutated rhyncogonus weevil | Rhyncogonus mutatus | Species of Concern | Wherever found | |
| Muticus eopenthes click beetle | Eopenthes muticus | Species of Concern | Wherever found | |
| Myers' pincushionplant | Navarretia myersii ssp. deminuta | Species of Concern | Wherever found | |
| Myrtle's silverspot butterfly | Speyeria zerene myrtleae | Endangered | Wherever found | 06-22-1992 |
| Mysore Ornamental Tarantula | Poecilotheria striata | Under Review | Wherever found | |
| mysterious lantern firefly | Photuris mysticalampas | Not Listed | | |
| Mystic cave beetle | Pseudanophthalmus hadenoecus | Species of Concern | Wherever found | |
| Naegele Springsnail | Pyrgulopsis metcalfi | Resolved Taxon | Wherever found | |
| Naenae | Dubautia kalalauensis | Endangered | Wherever found | 05-13-2010 |
| Naenae | Dubautia kenwoodii | Endangered | Wherever found | 05-13-2010 |
| Na`ena`e | Dubautia arborea | Species of Concern | Wherever found | |
| Na`ena`e | Dubautia herbstobatae | Endangered | Wherever found | 10-29-1991 |
| Na`ena`e | Dubautia imbricata ssp. imbricata | Endangered | Wherever found | 05-13-2010 |
| Na`ena`e | Dubautia knudsenii filiformis | Species of Concern | Wherever found | |
| Na`ena`e | Dubautia menziesii | Resolved Taxon | Wherever found | |
| Na`ena`e | Dubautia microcephala | Species of Concern | Wherever found | |
| Na`ena`e | Dubautia pauciflorula | Endangered | Wherever found | 09-20-1991 |
| Na`ena`e | Dubautia plantaginea ssp. humilis | Endangered | Wherever found | 09-03-1999 |
| Na`ena`e | Dubautia plantaginea ssp. magnifolia | Endangered | Wherever found | 05-13-2010 |
| Na`ena`e | Dubautia waialealae | Endangered | Wherever found | 05-13-2010 |
| Na`ena`e-pua-melemele | Dubautia laxa waianensis | Resolved Taxon | Wherever found | |
| Nahiku nesosydne planthopper | Nesosydne cyrtandrae | Species of Concern | Wherever found | |
| Naio | Myoporum sandwicense stellatum | Resolved Taxon | Wherever found | |
| Nama nama | nama stenocarpum | Species of Concern | Wherever found | |
| Naniha Goby, `O`Opu Naniha | Stenogobius hawaiiensis | Not Listed | | |
| Nani wai`ale`ale | Viola kauaiensis var. wahiawaensis | Endangered | Wherever found | 10-10-1996 |
| Nantucket short-tailed shrew | Blarina brevicauda compacta | Species of Concern | Wherever found | |
| Nanu | Gardenia mannii | Endangered | Wherever found | 10-10-1996 |
| Nanu | Gardenia remyi | Endangered | Wherever found | 10-31-2016 |
| Napa bluegrass | Poa napensis | Endangered | Wherever found | 10-22-1997 |
| Narrow catspaw | Epioblasma lenior | Resolved Taxon | Wherever found | |
| Narrow-foot hygrotus diving beetle | Hygrotus diversipes | Resolved Taxon | Wherever found | |
| Narrow-headed gartersnake | Thamnophis rufipunctatus | Threatened | Wherever found | 07-08-2014 |
| Narrowleaf Carolina scalystem | Elytraria caroliniensis angustifolia | Status Undefined | | |
| Narrowleaf evening-primrose | Oenothera acutissima | Resolved Taxon | Wherever found | |
| Narrow-leaved hedyotis | Hedyotis angusta umbrosa | Resolved Taxon | Wherever found | |
| Narrow-leaved nightshade | Solanum tenuilobatum | Species of Concern | Wherever found | |
| Narrownose smoothhound shark | Mustelus schmitti | Threatened | | |
| Narrow pigtoe | Fusconaia escambia | Threatened | Wherever found | 10-10-2012 |
| Narrow sawfish | Anoxypristis cuspidata | Endangered | Wherever found | 01-12-2015 |
| Narrows cave beetle | Pseudanophthalmus egberti | Not Listed | Wherever found | |
| Narrow-seeded yampah | Perideridia leptocarpa | Resolved Taxon | Wherever found | |
| Nashville crayfish | Orconectes shoupi | Endangered | Wherever found | 09-26-1986 |
| Nashville warbler | vermivora ruficapilla | Species of Concern | Wherever found | |
| Nashville waterweed | Elodea canadensis | Resolved Taxon | Wherever found | |
| Nassau grouper | Epinephelus striatus | Threatened | | 07-29-2016 |
| Natchez stonefly | Alloperla natchez | Species of Concern | Wherever found | |
| Native geranium | Geranium cuneatum hololeucum | Resolved Taxon | Wherever found | |
| (=Native yellow hibiscus) ma`o hau hele | Hibiscus brackenridgei | Endangered | Wherever found | 11-10-1994 |
| Natural Bridge cave beetle | Pseudanophthalmus pontis | Not Listed | Wherever found | |
| Naturita milk-vetch | Astragalus naturitensis | Resolved Taxon | Wherever found | |
| Navaho Mountain Mexican vole | Microtus mexicanus navaho | Species of Concern | Wherever found | |
| Navajo jerusalem cricket | Stenopelmatus navajo | Species of Concern | Wherever found | |
| Navajo Mountain phlox | Phlox cluteana | Resolved Taxon | Wherever found | |
| Navajo sedge | Carex specuicola | Threatened | Wherever found | 05-08-1985 |
| Navasota False Foxglove | Agalinis navasotensis | Proposed Endangered | Wherever found | |
| Navasota ladies-tresses | Spiranthes parksii | Endangered | Wherever found | 05-06-1982 |
| Navassa curley-tailed lizard | Leiocephalus eremitus | Resolved Taxon | Wherever found | |
| Navassa dusky dwarf boa | Tropidophis melanurus bucculentus | Species of Concern | Wherever found | |
| Navassa Island iguana | Cyclura cornuta nigerrima | Resolved Taxon | Wherever found | |
| Nearctic paduniellan caddisfly | Paduniella nearctica | Species of Concern | Wherever found | |
| Nebraska bog lemming | Synaptomys cooperi relictus | Resolved Taxon | Wherever found | |
| (Nebria gebleri cascadensis) ground beetle | nebria gebleri ssp. cascadensis | Species of Concern | Wherever found | |
| (Nebria kincaidi balli) ground beetle | nebria kincaidi ssp. balli | Species of Concern | Wherever found | |
| (Nebria paradisi) ground beetle | nebria paradisi | Species of Concern | Wherever found | |
| Neches Crayfish | Procambarus nechesae | Resolved Taxon | Wherever found | |
| Neches River rose-mallow | Hibiscus dasycalyx | Threatened | Wherever found | 10-11-2013 |
| Necker bunchgrass seed bug | Nysius suffusus | Species of Concern | Wherever found | |
| Necker goosefoot seed bug | Nysius neckerensis | Species of Concern | Wherever found | |
| Necker itodacnus click beetle | Itodacnus novicornis | Species of Concern | Wherever found | |
| Necker oodemas weevil | Oodemas neckeri | Species of Concern | Wherever found | |
| Necker petrochroan leaf miner | Hyposmocoma neckerensis | Species of Concern | Wherever found | |
| Necker rhyncogonus weevil | Rhyncogonus biformis | Species of Concern | Wherever found | |
| Necklace gladecress | Leavenworthia torulosa | Resolved Taxon | Wherever found | |
| Needleleaf waternymph | Najas filifolia | Under Review | Wherever found | |
| Needle palm | Rhapidophyllum hystrix | Resolved Taxon | Wherever found | |
| Needles knotweed | Persicaria maculosa | Resolved Taxon | Wherever found | |
| Negro mato | Caesalpinia monensis | Resolved Taxon | Wherever found | |
| Negros Naked-Backed Fruit Bat | Dobsonia chapmani | Under Review | Wherever found | |
| nehe | Lipochaeta fauriei | Endangered | Wherever found | 02-25-1994 |
| nehe | Lipochaeta lobata var. leptophylla | Endangered | Wherever found | 10-29-1991 |
| nehe | Lipochaeta lobata var. lobata | Resolved Taxon | Wherever found | |
| nehe | Lipochaeta micrantha | Endangered | Wherever found | 02-25-1994 |
| nehe | Lipochaeta venosa | Endangered | Wherever found | 11-29-1979 |
| nehe | Lipochaeta waimeaensis | Endangered | Wherever found | 02-25-1994 |
| nehe | Melanthera kamolensis | Endangered | Wherever found | 05-15-1992 |
| nehe | Melanthera populifolia | Resolved Taxon | Wherever found | |
| nehe | Melanthera subcordata | Resolved Taxon | Wherever found | |
| nehe | Melanthera tenuifolia | Endangered | Wherever found | 10-29-1991 |
| Nehe | Lipochaeta integrifolia gracilis | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta integrifolia major | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta integrifolia megacephala | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta lavarum longifolia | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta lavarum salicifolia | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta lavarum skottsbergii | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta perdita | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta profusa robustior | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta subcordata membranacea | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta succulenta succulenta | Resolved Taxon | Wherever found | |
| Nehe | Lipochaeta tenuis | Species of Concern | Wherever found | |
| Nehe kuhiwa | Phyllostegia electra | Resolved Taxon | Wherever found | |
| Nekogigi (catfish) | Coreobagrus ichikawai | Endangered | Wherever found | 06-02-1970 |
| Nellie''s cory cactus | Escobaria minima | Endangered | Wherever found | 12-08-1979 |
| Nelson's antelope ground squirrel | Ammospermophilus nelsoni | Species of Concern | Wherever found | |
| Nelson's cave beetle | Pseudanophthalmus nelsoni | Species of Concern | Wherever found | |
| Nelson's checker-mallow | Sidalcea nelsoniana | Recovery | Wherever found | 02-12-1993 |
| Nelson's miloderes weevil | Miloderes nelsoni | Species of Concern | Wherever found | |
| Nelson's Sparrow | Ammodramus nelsoni | Species of Concern | Wherever found | |
| Neojuvenile tiger beetle | Cicindela obsoleta neojuvenilis | Species of Concern | Wherever found | |
| Neosho madtom | Noturus placidus | Threatened | Wherever found | 05-22-1990 |
| Neosho Mucket | Lampsilis rafinesqueana | Endangered | Wherever found | 10-17-2013 |
| Nerite pebblesnail | Fluminicola spc | Resolved Taxon | Wherever found | |
| Neritiform Steptoe Ranch pyrg | Pyrgulopsis neritella | Under Review | Wherever found | |
| Neuse River waterdog | Necturus lewisi | Threatened | Wherever found | 07-09-2021 |
| Neuse slabshell | Elliptio judithae | Species of Concern | Wherever found | |
| Nevada admiral | Limenitus weidemeyerii nevadae | Species of Concern | Wherever found | |
| Nevada oryctes | Oryctes nevadensis | Species of Concern | Wherever found | |
| Nevada viceroy | Limenitus archippus lahontani | Species of Concern | Wherever found | |
| Nevada waterweed | Elodea bifoliata | Resolved Taxon | Wherever found | |
| Nevada willowherb | Epilobium nevadense | Species of Concern | Wherever found | |
| Nevares Spring naucorid bug (=Furnace Creek) | Ambrysus funebris | Resolved Taxon | Wherever found | |
| Nevin's barberry | Berberis nevinii | Endangered | Wherever found | 10-13-1998 |
| Nevin's wooly-sunflower | Eriophyllum nevinii | Species of Concern | Wherever found | |
| Nevius' stonecrop | Sedum nevii | Species of Concern | Wherever found | |
| Newark Valley tui chub | Siphateles bicolor newarkensis | Species of Concern | Wherever found | |
| New Caledonia Long-Eared Bat | Nyctophilus nebulosus | Under Review | Wherever found | |
| New Comanche Trail cave harvestman | texella | Species of Concern | Wherever found | |
| Newcomb's littorine snail | Algamorda newcombiana | Species of Concern | Wherever found | |
| Newcomb's snail | Erinna newcombi | Threatened | Wherever found | 01-26-2000 |
| Newcomb's tree snail | Newcombia canaliculata | Species of Concern | Wherever found | |
| Newcomb's tree snail | Newcombia perkinsi | Species of Concern | Wherever found | |
| Newcomb's tree snail | Newcombia pfeifferi | Species of Concern | Wherever found | |
| Newcomb's tree snail | Newcombia sulcata | Species of Concern | Wherever found | |
| Newcomb's tree snail | Nucombia plicata | Species of Concern | Wherever found | |
| Newcomb's Tree snail | Newcombia cumingi | Endangered | Wherever found | 06-27-2013 |
| Newell''s shearwater | Puffinus newelli | Threatened | Wherever found | 10-28-1975 |
| New England cottontail | Sylvilagus transitionalis | Resolved Taxon | Wherever found | |
| New England violet | Viola novae-angliae | Resolved Taxon | Wherever found | |
| New Guinea birdwing butterfly | Ornithoptera meridionalis | Resolved Taxon | Wherever found | |
| New Holland mouse | Pseudomys novaehollandiae | Endangered | Wherever found | 12-02-1970 |
| New Jersey rush | Juncus caesariensis | Species of Concern | Wherever found | |
| New Mammoth Cave cave beetle | Pseudanophthalmus scutilis | Species of Concern | Wherever found | |
| New Mexican ridge-nosed rattlesnake | Crotalus willardi obscurus | Threatened | Wherever found | 08-21-1978 |
| New Mexico meadow jumping mouse | Zapus hudsonius luteus | Endangered | Wherever found | 07-10-2014 |
| New Mexico Ramshorn snail | Pecosorbis kansasensis | Resolved Taxon | Wherever found | |
| New Mexico springsnail | Pyrgulopsis thermalis | Resolved Taxon | Wherever found | |
| New River riffle crayfish | Cambarus chasmodactylus | Not Listed | Wherever found | |
| New York Mountains cryptantha | Cryptantha tumulosa | Resolved Taxon | Wherever found | |
| New Zealand bushwren | Xenicus longipes | Endangered | Wherever found | 06-02-1970 |
| New Zealand Greater Short-Tailed Bat | Mystacina robusta | Under Review | Wherever found | |
| New Zealand shore plover | Thinornis novaeseelandiae | Endangered | Wherever found | 06-02-1970 |
| New Zealand thrush (wattlebird) | Turnagra capensis | Endangered | Wherever found | 06-02-1970 |
| Niangua darter | Etheostoma nianguae | Threatened | Wherever found | 06-12-1985 |
| Niceforo's wren | Thryothorus nicefori | Status Undefined | Wherever found | |
| Nichol's Turk's head cactus | Echinocactus horizonthalonius var. nicholii | Endangered | Wherever found | 11-28-1979 |
| Nickajack Cave beetle | Pseudanophthalmus nickajackensis | Resolved Taxon | Wherever found | |
| Nickajack Cave isopod | Caecidotea nickajackensis | Species of Concern | Wherever found | |
| Nickel's cory cactus | Coryphantha sulcata nickelsiae | Species of Concern | Wherever found | |
| Nickerbean Blue Butterfly | Cyclargus ammon | Similarity of Appearance (Threatened) | Wherever found | 04-06-2012 |
| Nicklin's pearlymussel | Megalonaias nicklineana | Endangered | Wherever found | 06-14-1976 |
| Night (=Australian) parrot | Geopsittacus occidentalis | Endangered | Wherever found | 06-02-1970 |
| Nightingale reed warbler (old world warbler) | Acrocephalus luscinia | Endangered | Wherever found | 06-02-1970 |
| Nigrohamatum megalagrion damselfly | Megalagrion nigrohamatum nigrohamatum | Species of Concern | Wherever found | |
| Nihoa banza conehead katydid | Banza nihoa | Species of Concern | Wherever found | |
| Nihoa eupelmus wasp | Eupelmus nihoaensis | Species of Concern | Wherever found | |
| Nihoa finch | Telespiza ultima | Endangered | Wherever found | 03-11-1967 |
| Nihoa long-horned beetle | Plagithmysus nihoae | Species of Concern | Wherever found | |
| Nihoa millerbird (old world warbler) | Acrocephalus familiaris kingi | Endangered | Wherever found | 03-11-1967 |
| Nihoa nysius seed bug | Nysius nihoae | Species of Concern | Wherever found | |
| Nihoa oodemas weevil | Oodemas breviscapum | Species of Concern | Wherever found | |
| Nihoa rhyncogonus weevil | Rhyncogonus exsul | Species of Concern | Wherever found | |
| Nihoa sclerodermus wasp | Sclerodermus nihoaensis | Species of Concern | Wherever found | |
| Nihoa stenotrupis weevil | Stenotrupis pritcharsdiae | Species of Concern | Wherever found | |
| Nihoa two-spotted asteriid fly | Bryania bipunctata | Species of Concern | Wherever found | |
| Ni`ihau love grass | Eragrostis variabilis | Resolved Taxon | Wherever found | |
| Niihau odynerus vespid wasp | Odynerus niihauensis | Species of Concern | Wherever found | |
| Nile crocodile | Crocodylus niloticus | Threatened | Wherever found | 06-02-1970 |
| Nine Mile Canyon phacelia | Phacelia novenmillensis | Species of Concern | Wherever found | |
| Ninemile Pyrg | Pyrgulopsis nonaria | Resolved Taxon | Wherever found | |
| Nino de cota | Laplacea portoricensis | Resolved Taxon | Wherever found | |
| Nioi | Eugenia koolauensis | Endangered | Wherever found | 03-28-1994 |
| Nipomo ceanothus | Ceanothus impressus nipomensis | Resolved Taxon | Wherever found | |
| Nipomo Mesa lupine | Lupinus nipomensis | Endangered | Wherever found | 03-20-2000 |
| Nipple Bench phacelia | Phacelia mammillarensis | Resolved Taxon | Wherever found | |
| Nissenan manzanita | Arctostaphylos nissenana | Species of Concern | Wherever found | |
| Nixon's Hawthorn | Crataegus nananixonii | Resolved Taxon | Wherever found | |
| Nobletts cave beetle | Pseudanophthalmus paulus | Resolved Taxon | Wherever found | |
| No comment name | phytolacca sandwicensis | Species of Concern | Wherever found | |
| no common name | Amerigoniscus gipsocolus | Under Review | Wherever found | |
| no common name | Artesia subterranea | Resolved Taxon | Wherever found | |
| No common name | Abronia ammophila var. | Species of Concern | Wherever found | |
| No common name | Abutilon eremitopetalum | Endangered | Wherever found | 09-20-1991 |
| No common name | Abutilon parishii | Species of Concern | Wherever found | |
| No common name | Abutilon sandwicense | Endangered | Wherever found | 10-29-1991 |
| No common name | Abutilon virginianum | Species of Concern | Wherever found | |
| No common name | Acanthastrea brevis | Status Undefined | Wherever found | |
| No common name | Acanthastrea hemprichii | Status Undefined | Wherever found | |
| No common name | Acanthastrea ishigakiensis | Status Undefined | Wherever found | |
| No common name | Acanthastrea regularis | Status Undefined | Wherever found | |
| No common name | acarospora clauzadeana | Status Undefined | Wherever found | |
| No common name | Achnatherum contractum | Species of Concern | Wherever found | |
| No common name | Achnatherum curvifolium | Resolved Taxon | Wherever found | |
| No common name | Achnatherum swallenii | Resolved Taxon | Wherever found | |
| No common name | Achyranthes atollensis | Resolved Taxon | Wherever found | |
| No common name | Achyranthes mutica | Endangered | Wherever found | 10-10-1996 |
| No common name | Achyranthes splendens splendens | Resolved Taxon | Wherever found | |
| No common name | Acrocephalus nijoi | Species of Concern | | |
| No common name | Acrocephalus yamashinae | Species of Concern | | |
| No common name | Acropora aculeus | Status Undefined | Wherever found | |
| No common name | Acropora acuminata | Status Undefined | Wherever found | |
| No common name | Acropora aspera | Status Undefined | Wherever found | |
| No common name | Acropora cuneata | Status Undefined | Wherever found | |
| No common name | Acropora dendrum | Status Undefined | Wherever found | |
| No common name | Acropora donei | Status Undefined | Wherever found | |
| No common name | Acropora globiceps | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora horrida | Status Undefined | Wherever found | |
| No common name | Acropora jacquelineae | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora listeri | Status Undefined | Wherever found | |
| No common name | Acropora lokani | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora microclados | Status Undefined | Wherever found | |
| No common name | Acropora palmerae | Status Undefined | Wherever found | |
| No common name | Acropora paniculata | Status Undefined | Wherever found | |
| No common name | Acropora pharaonis | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora polystoma | Status Undefined | Wherever found | |
| No common name | Acropora retusa | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora rudis | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora speciosa | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora striata | Status Undefined | Wherever found | |
| No common name | Acropora tenella | Threatened | Wherever found | 11-13-2014 |
| No common name | Acropora vaughani | Status Undefined | Wherever found | |
| No common name | Acropora verweyi | Status Undefined | Wherever found | |
| No common name | Adiantum vivesii | Original Data in Error - Not a listable entity | Wherever found | 06-09-1993 |
| No common name | Aerva sericea | Resolved Taxon | Wherever found | |
| No common name | Agalinis purpurea carteri | Resolved Taxon | Wherever found | |
| No common name | Agastache cusickii | Resolved Taxon | Wherever found | |
| No common name | agathon arizonicus | Resolved Taxon | Wherever found | |
| No common name | Agave eggersiana | Endangered | Wherever found | 10-09-2014 |
| No common name | Agave mckelveyana | Resolved Taxon | Wherever found | |
| No common name | Agave murpheyi | Species of Concern | Wherever found | |
| No common name | Agave schottii treleasei | Species of Concern | Wherever found | |
| No common name | Agave toumeyana bella | Resolved Taxon | Wherever found | |
| No common name | Agave utahensis kaibabensis | Resolved Taxon | Wherever found | |
| No common name | Ageratina luciae-brauniae | Species of Concern | Wherever found | |
| No common name | Agropsar philippensis | Species of Concern | | |
| No common name | agylla septentrionalis | Resolved Taxon | Wherever found | |
| No common name | Akialoa ellisiana | Species of Concern | | |
| No common name | Akialoa lanaiensis | Species of Concern | | |
| No common name | albiorix anophthalmus | Resolved Taxon | Wherever found | |
| No common name | Aletes filifolius | Resolved Taxon | Wherever found | |
| No common name | Aletes humilis | Species of Concern | Wherever found | |
| No common name | alexicles aspersa | Resolved Taxon | Wherever found | |
| No common name | Allionia cristata | Resolved Taxon | Wherever found | |
| No common name | Allomyia hector | Resolved Taxon | Wherever found | |
| No common name | Allowissadula holosericea | Resolved Taxon | Wherever found | |
| No common name | Alopecoenas stairi | Species of Concern | | |
| No common name | Alsophila brooksii | Resolved Taxon | Wherever found | |
| No common name | Alveopora allingi | Status Undefined | Wherever found | |
| No common name | Alveopora fenestrata | Status Undefined | Wherever found | |
| No common name | Alveopora verrilliana | Status Undefined | Wherever found | |
| No common name | Amaranthus brownii | Endangered | Wherever found | 08-21-1996 |
| No common name | Ameletus edmundsi | Resolved Taxon | Wherever found | |
| No common name | amergoniscus centalis | Status Undefined | Wherever found | |
| No common name | amergoniscus gipsocolus | Resolved Taxon | Wherever found | |
| No common name | Amorpha canescens | Resolved Taxon | Wherever found | |
| No common name | Amsonia fugatei | Species of Concern | Wherever found | |
| No common name | Amsonia tabernaemontana gattingeri | Species of Concern | Wherever found | |
| No common name | Anacropora puertogalerae | Status Undefined | Wherever found | |
| No common name | Anacropora spinosa | Threatened | Wherever found | 11-13-2014 |
| No common name | Angelica scabrida | Species of Concern | Wherever found | |
| No common name | Angelica wheeleri | Resolved Taxon | Wherever found | |
| No common name | Anser serrirostris | Species of Concern | | |
| No common name | Antennaria aromatica | Resolved Taxon | Wherever found | |
| No common name | Antennaria soliceps | Species of Concern | Wherever found | |
| No common name | Apacheria chiricahuensis | Resolved Taxon | Wherever found | |
| No common name | Aphrastochthonius pachysetus | Resolved Taxon | Wherever found | |
| No common name | apocheiridium reddelli | Resolved Taxon | Wherever found | |
| No common name | Aquilegia barnebyi | Resolved Taxon | Wherever found | |
| No common name | Aquilegia caerulea daileyae | Resolved Taxon | Wherever found | |
| No common name | Aquilegia desertorum | Resolved Taxon | Wherever found | |
| No common name | Aquilegia saximontana | Resolved Taxon | Wherever found | |
| No common name | Arabis missouriensis deamii | Species of Concern | Wherever found | |
| No common name | Arabis suffrutescens horizontalis | Species of Concern | Wherever found | |
| No common name | Arceuthobium apachense | Resolved Taxon | Wherever found | |
| No common name | archeolarca welbourni | Resolved Taxon | Wherever found | |
| No common name | Ardea intermedia | Species of Concern | | |
| No common name | Arenaria franklinii thompsonii | Resolved Taxon | Wherever found | |
| No common name | Arenaria kingii rosea | Species of Concern | Wherever found | |
| No common name | Arenaria stenomeres | Resolved Taxon | Wherever found | |
| No common name | Argemone glauca inermis | Resolved Taxon | Wherever found | |
| No common name | arida mattturneri | Resolved Taxon | Wherever found | |
| No common name | Aristida chaseae | Endangered | Wherever found | 04-27-1993 |
| No common name | Arnica amplexicaulis piperi | Resolved Taxon | Wherever found | |
| No common name | Arnica cordifolia | Resolved Taxon | Wherever found | |
| No common name | Arnica lonchophylla | Species of Concern | Wherever found | |
| No common name | Arnica venosa | Resolved Taxon | Wherever found | |
| No common name | Artemisia biennis diffusa | Species of Concern | Wherever found | |
| No common name | Artemisia ludoviciana estesii | Species of Concern | Wherever found | |
| No common name | Artemisia papposa | Resolved Taxon | Wherever found | |
| No common name | Artemisia unalaskensis aleutica | Resolved Taxon | Wherever found | |
| No common name | Artemisiospiza belli | Species of Concern | | |
| No common name | Artesia welbourni | Resolved Taxon | Wherever found | |
| No common name | Arundinax aedon | Species of Concern | | |
| No common name | Asplenium dielerectum | Endangered | Wherever found | 11-10-1994 |
| No common name | Asplenium diellaciniatum | Endangered | Wherever found | 10-31-2016 |
| No common name | Asplenium (=Diellia) dielfalcatum (=falcata) | Endangered | Wherever found | 10-29-1991 |
| No common name | Asplenium dielmannii | Endangered | Wherever found | 05-13-2010 |
| No common name | Asplenium dielpallidum | Endangered | Wherever found | 02-25-1994 |
| No common name | Asplenium peruvianum var. insulare | Endangered | Wherever found | 09-26-1994 |
| No common name | Asplenium schizophyllum | Species of Concern | Wherever found | |
| No common name | Asplenium unisorum | Endangered | Wherever found | 06-27-1994 |
| No common name | Aster kingii barnebyana | Species of Concern | Wherever found | |
| No common name | Astragalus amphioxys musimonum | Species of Concern | Wherever found | |
| No common name | Astragalus avonensis | Resolved Taxon | Wherever found | |
| No common name | Astragalus collinus laurentii | Species of Concern | Wherever found | |
| No common name | Astragalus diaphanus diurnus | Species of Concern | Wherever found | |
| No common name | Astragalus gilviflorus var. purpureus | Species of Concern | Wherever found | |
| No common name | Astragalus jejunus articulatus | Species of Concern | Wherever found | |
| No common name | Astragalus lentiginosus ambiguus | Species of Concern | Wherever found | |
| No common name | Astragalus lentiginosus antonius | Species of Concern | Wherever found | |
| No common name | Astragalus limnocharis limnocharis | Species of Concern | Wherever found | |
| No common name | Astragalus limnocharis tabulaeus | Species of Concern | Wherever found | |
| No common name | Astragalus oophorus lonchocalyx | Species of Concern | Wherever found | |
| No common name | Astragalus pulsiferae suksdorfii | Species of Concern | Wherever found | |
| No common name | Astragalus subcinereus basalticus | Species of Concern | Wherever found | |
| No common name | Astragalus vexilliflexus nubilus | Species of Concern | Wherever found | |
| No common name | Astranthium robustum | Resolved Taxon | Wherever found | |
| No common name | Astreopora cucullata | Status Undefined | Wherever found | |
| No common name | Atriplex canescens gigantea | Species of Concern | Wherever found | |
| No common name | Atriplex welshii | Resolved Taxon | Wherever found | |
| No common name | Auerodendron pauciflorum | Endangered | Wherever found | 03-02-1994 |
| No common name | Aureolaria patula | Species of Concern | Wherever found | |
| No common name | Bahia bigelovii | Resolved Taxon | Wherever found | |
| No common name | Balsamorhiza rosea | Resolved Taxon | Wherever found | |
| No common name | Balsamorhiza sericea | Resolved Taxon | Wherever found | |
| No common name | Baptisia calycosa calycosa | Species of Concern | Wherever found | |
| No common name | Baptisia simplicifolia | Species of Concern | Wherever found | |
| No common name | Barabattoai laddi | Status Undefined | Wherever found | |
| No common name | Basiphyllaea corallicola | Resolved Taxon | Wherever found | |
| No common name | Batrisodes grubbsi | Resolved Taxon | Wherever found | |
| No common name | Bazzania nudicaulis | Species of Concern | Wherever found | |
| No common name | Besseya bullii | Resolved Taxon | Wherever found | |
| No common name | Betta hendra | Under Review | | |
| No common name | Betta miniopinna | Not Listed | | |
| No common name | Betta rutilans | Under Review | | |
| No common name | Blancosoma scaturgo | Resolved Taxon | Wherever found | |
| No common name | Bonamia menziesii | Endangered | Wherever found | 11-10-1994 |
| No common name | Bothriochloa exaristata | Resolved Taxon | Wherever found | |
| No common name | Botrychium crenulatum | Species of Concern | Wherever found | |
| No common name | Botrychium mormo | Species of Concern | Wherever found | |
| No common name | Botrychium pallidum | Species of Concern | Wherever found | |
| No common name | Botrychium paradoxum | Species of Concern | Wherever found | |
| No common name | Brachycercus tuberculatus | Resolved Taxon | Wherever found | |
| No common name | Brassia caudata | Resolved Taxon | Wherever found | |
| No common name | Braya humilis leiocarpa | Resolved Taxon | Wherever found | |
| No common name | Brickellia dentata | Resolved Taxon | Wherever found | |
| No common name | Brickellia leptophylla | Resolved Taxon | Wherever found | |
| No common name | Bromus texensis | Resolved Taxon | Wherever found | |
| No common name | Brunfelsia portoricensis | Species of Concern | Wherever found | |
| No common name | Caecidotea bisetus | Resolved Taxon | Wherever found | |
| No common name | Caecidotea metcalfi | Resolved Taxon | Wherever found | |
| No common name | Caecidotea tridentata | Species of Concern | Wherever found | |
| No common name | Caesalpinia drummondii | Resolved Taxon | Wherever found | |
| No common name | Calidris falcinellus | Species of Concern | | |
| No common name | Calidris pygmea | Species of Concern | | |
| No common name | Calliandra locoensis | Resolved Taxon | Wherever found | |
| No common name | Calliope calliope | Species of Concern | | |
| No common name | Calochortus nitidus | Species of Concern | Wherever found | |
| No common name | Calochortus weedii vestus | Species of Concern | Wherever found | |
| No common name | Calyptranthes estremerae | Resolved Taxon | Wherever found | |
| No common name | Calyptranthes luquillensis | Species of Concern | Wherever found | |
| No common name | Calyptranthes peduncularis | Species of Concern | Wherever found | |
| No common name | Calyptranthes thomasiana | Endangered | Wherever found | 02-18-1994 |
| No common name | Calyptranthes triflorum | Species of Concern | Wherever found | |
| No common name | Camassia cusickii | Resolved Taxon | Wherever found | |
| No common name | Camassia howellii | Species of Concern | Wherever found | |
| No common name | Camissonia atwoodii | Species of Concern | Wherever found | |
| No common name | Campanula rotundifolia sacajaweana | Resolved Taxon | Wherever found | |
| No common name | Cantharellus noumeae | Endangered | | 11-06-2015 |
| No common name | Cardamine penduliflora | Resolved Taxon | Wherever found | |
| No common name | Carex wahuensis herbstii | Species of Concern | Wherever found | |
| No common name | Carpodacus roseus | Species of Concern | | |
| No common name | Cassia fasciculata macrosperma | Species of Concern | Wherever found | |
| No common name | Castilleja annua | Resolved Taxon | Wherever found | |
| No common name | Castilleja fraterna | Species of Concern | Wherever found | |
| No common name | Castilleja glandulifera | Resolved Taxon | Wherever found | |
| No common name | Castilleja linoides | Resolved Taxon | Wherever found | |
| No common name | Castilleja nervata | Resolved Taxon | Wherever found | |
| No common name | Castilleja oresbia | Resolved Taxon | Wherever found | |
| No common name | Castilleja parviflora olympica | Resolved Taxon | Wherever found | |
| No common name | Castilleja rubida | Species of Concern | Wherever found | |
| No common name | Castilleja xanthotricha | Resolved Taxon | Wherever found | |
| No common name | catapyrenium granulosum | Resolved Taxon | Wherever found | |
| No common name | Catesbaea melanocarpa | Endangered | Wherever found | 03-17-1999 |
| No common name | Catinella texana | Resolved Taxon | Wherever found | |
| No common name | Caulastraea echinulata | Status Undefined | Wherever found | |
| No common name | Ceanothus arboreus glaber | Species of Concern | Wherever found | |
| No common name | Ceratopsyche vanaca | Resolved Taxon | Wherever found | |
| No common name | ceuthothrombium cavaticum | Resolved Taxon | Wherever found | |
| No common name | Chaenactis cusickii | Species of Concern | Wherever found | |
| No common name | Chaenactis evermannii | Resolved Taxon | Wherever found | |
| No common name | Chaenactis nevii | Resolved Taxon | Wherever found | |
| No common name | Chaenactis ramosa | Resolved Taxon | Wherever found | |
| No common name | Chaenactis thompsonii | Resolved Taxon | Wherever found | |
| No common name | Chamaechaenactis scaposa | Resolved Taxon | Wherever found | |
| No common name | Chamaecrista glandulosa var. mirabilis | Endangered | Wherever found | 04-05-1990 |
| No common name | Chamaerhodos nuttallii keweenawensis | Species of Concern | Wherever found | |
| No common name | Chamaesyce celastroides stokesii | Resolved Taxon | Wherever found | |
| No common name | Chamaesyce cumulicola | Species of Concern | Wherever found | |
| No common name | Chamaesyce jejuna | Resolved Taxon | Wherever found | |
| No common name | Chamaesyce multiformis multiformis | Resolved Taxon | Wherever found | |
| No common name | Chamaesyce ocellata rattanii | Resolved Taxon | Wherever found | |
| No common name | Chamaesyce porteriana porteriana | Species of Concern | Wherever found | |
| No common name | Cheilolejeunea evansii | Species of Concern | Wherever found | |
| No common name | cheiridium reyesi | Resolved Taxon | Wherever found | |
| No common name | Cheirodendron helleri helleri | Resolved Taxon | Wherever found | |
| No common name | Cheirodendron helleri microcarpum | Resolved Taxon | Wherever found | |
| No common name | Cheirodendron helleri sodalium | Resolved Taxon | Wherever found | |
| No common name | Chelone obliqua speciosa | Resolved Taxon | Wherever found | |
| No common name | Chenopodium oahuense discospermum | Resolved Taxon | Wherever found | |
| No common name | Chiloscyphus gemmiparus | Resolved Taxon | Wherever found | |
| No common name | chitrella elliotti | Resolved Taxon | Wherever found | |
| No common name | chitrella major | Resolved Taxon | Wherever found | |
| No common name | chitrella welbourni | Resolved Taxon | Wherever found | |
| No common name | chitrellina chiricahuae | Resolved Taxon | Wherever found | |
| No common name | Chorizanthe polygonoides longispina | Species of Concern | Wherever found | |
| No common name | Chromolaena borinquensis | Species of Concern | Wherever found | |
| No common name | Chromolaena oteroi | Species of Concern | Wherever found | |
| No common name | Chrysophyllum cainito | Species of Concern | Wherever found | |
| No common name | Chrysosplenium iowense | Species of Concern | Wherever found | |
| No common name | Chrysothamnus eremobius | Species of Concern | Wherever found | |
| No common name | Chrysothamnus molestus | Species of Concern | Wherever found | |
| No common name | Chrysothamnus nauseosus nanus | Resolved Taxon | Wherever found | |
| No common name | Chrysothamnus nauseosus texensis | Species of Concern | Wherever found | |
| No common name | Chrysothamnus parryi hinckleyi | Species of Concern | Wherever found | |
| No common name | Chrysothamnus scopulorum | Resolved Taxon | Wherever found | |
| No common name | cicurina barri | Resolved Taxon | Wherever found | |
| No common name | cicurina browni | Resolved Taxon | Wherever found | |
| No common name | cicurina caverna | Resolved Taxon | Wherever found | |
| No common name | cicurina coryelli | Resolved Taxon | Wherever found | |
| No common name | cicurina ezelli | Resolved Taxon | Wherever found | |
| No common name | cicurina gruta | Resolved Taxon | Wherever found | |
| No common name | cicurina holsingeri | Resolved Taxon | Wherever found | |
| No common name | cicurina machete | Resolved Taxon | Wherever found | |
| No common name | cicurina mckenziei | Resolved Taxon | Wherever found | |
| No common name | cicurina medina | Resolved Taxon | Wherever found | |
| No common name | cicurina menardia | Resolved Taxon | Wherever found | |
| No common name | cicurina obscura | Resolved Taxon | Wherever found | |
| No common name | cicurina orellia | Resolved Taxon | Wherever found | |
| No common name | cicurina pablo | Resolved Taxon | Wherever found | |
| No common name | cicurina pastura | Resolved Taxon | Wherever found | |
| No common name | cicurina patei | Resolved Taxon | Wherever found | |
| No common name | cicurina porteri | Resolved Taxon | Wherever found | |
| No common name | cicurina puentecilla | Resolved Taxon | Wherever found | |
| No common name | cicurina rainesi | Resolved Taxon | Wherever found | |
| No common name | cicurina reclusa | Resolved Taxon | Wherever found | |
| No common name | cicurina reddelli | Resolved Taxon | Wherever found | |
| No common name | cicurina reyesi | Resolved Taxon | Wherever found | |
| No common name | cicurina russelli | Resolved Taxon | Wherever found | |
| No common name | cicurina sansaba | Resolved Taxon | Wherever found | |
| No common name | cicurina selecta | Resolved Taxon | Wherever found | |
| No common name | cicurina serena | Resolved Taxon | Wherever found | |
| No common name | cicurina sheari | Resolved Taxon | Wherever found | |
| No common name | cicurina sprousei | Resolved Taxon | Wherever found | |
| No common name | cicurina stowersi | Resolved Taxon | Wherever found | |
| No common name | cicurina suttoni | Resolved Taxon | Wherever found | |
| No common name | cicurina travisae | Resolved Taxon | Wherever found | |
| No common name | cicurina ubicki | Resolved Taxon | Wherever found | |
| No common name | cicurina uvalde | Resolved Taxon | Wherever found | |
| No common name | cicurina venefica | Resolved Taxon | Wherever found | |
| No common name | cicurina vibora | Resolved Taxon | Wherever found | |
| No common name | cicurina watersi | Resolved Taxon | Wherever found | |
| No common name | Cimicifuga laciniata | Resolved Taxon | Wherever found | |
| No common name | Cimicifuga rubifolia | Species of Concern | Wherever found | |
| No common name | cisthene conjuncta | Resolved Taxon | Wherever found | |
| No common name | Cladrastis kentukea | Resolved Taxon | Wherever found | |
| No common name | Claytonia lanceolata chrysantha | Resolved Taxon | Wherever found | |
| No common name | Claytonia lanceolata flava | Species of Concern | Wherever found | |
| No common name | Claytonia megarhiza nivalis | Resolved Taxon | Wherever found | |
| No common name | Cleomella palmeriana | Resolved Taxon | Wherever found | |
| No common name | Clermontia hawaiiensis hawaiiensis | Resolved Taxon | Wherever found | |
| No common name | Clermontia konaensis | Resolved Taxon | Wherever found | |
| No common name | Clermontia loyana | Resolved Taxon | Wherever found | |
| No common name | Clermontia multiflora | Resolved Taxon | Wherever found | |
| No common name | Clermontia munroi | Resolved Taxon | Wherever found | |
| No common name | Clinopodium ashei | Species of Concern | Wherever found | |
| No common name | Clinopodium dentatum | Resolved Taxon | Wherever found | |
| No common name | Clusia flava | Resolved Taxon | Wherever found | |
| No common name | Coccoloba rugosa | Resolved Taxon | Wherever found | |
| No common name | Cocculus orbiculatus | Resolved Taxon | Wherever found | |
| No common name | Coccyzus vieilloti | Species of Concern | | |
| No common name | Coelorachis tuberculosa | Species of Concern | Wherever found | |
| No common name | Collinsia antonina | Species of Concern | Wherever found | |
| No common name | Collomia renacta | Species of Concern | Wherever found | |
| No common name | Columbiadoria hallii | Resolved Taxon | Wherever found | |
| No common name | Conostegia rufescens | Species of Concern | Wherever found | |
| No common name | Coprosma faurei lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Coprosma montana orbicularis | Resolved Taxon | Wherever found | |
| No common name | Coprosma ochracea kaalae | Resolved Taxon | Wherever found | |
| No common name | Coprosma pubens | Resolved Taxon | Wherever found | |
| No common name | Coprosma pubens sessiliflora | Resolved Taxon | Wherever found | |
| No common name | Cordia bellonis | Endangered | Wherever found | 01-10-1997 |
| No common name | Cordia wagnerorum | Species of Concern | Wherever found | |
| No common name | Coreopsis grandiflora | Resolved Taxon | Wherever found | |
| No common name | Coreopsis latifolia | Resolved Taxon | Wherever found | |
| No common name | Coreopsis pulchra | Resolved Taxon | Wherever found | |
| No common name | Coreopsis tripteris subrhomboidea | Resolved Taxon | Wherever found | |
| No common name | Corydalis aquae-gelidae | Species of Concern | Wherever found | |
| No common name | Corydalis caseana brachycarpa | Resolved Taxon | Wherever found | |
| No common name | Corydalis caseana hastata | Resolved Taxon | Wherever found | |
| No common name | Coryphantha dasyacantha dasyacantha | Species of Concern | Wherever found | |
| No common name | Coryphantha dasyacantha varicolor | Resolved Taxon | Wherever found | |
| No common name | Coursetia axillaris | Resolved Taxon | Wherever found | |
| No common name | Coursetia glabella | Species of Concern | Wherever found | |
| No common name | Cranichis ricartii | Endangered | Wherever found | 11-29-1991 |
| No common name | Crataegus stenosepala | Resolved Taxon | Wherever found | |
| No common name | Crataegus sutherlandensis | Resolved Taxon | Wherever found | |
| No common name | Crataegus triflora | Species of Concern | Wherever found | |
| No common name | Crossosoma bigelovii | Resolved Taxon | Wherever found | |
| No common name | Croton fishlockii | Species of Concern | Wherever found | |
| No common name | Croton glandulosus simpsonii | Resolved Taxon | Wherever found | |
| No common name | Croton impressus | Resolved Taxon | Wherever found | |
| No common name | Croton microcarpus | Resolved Taxon | Wherever found | |
| No common name | Cryptantha cinerea arenicola | Species of Concern | Wherever found | |
| No common name | Cryptantha creutzfeldtii | Species of Concern | Wherever found | |
| No common name | Cryptantha interrupta | Resolved Taxon | Wherever found | |
| No common name | Cryptantha mensana | Resolved Taxon | Wherever found | |
| No common name | Cryptantha paradoxa | Resolved Taxon | Wherever found | |
| No common name | Cryptantha rollinsii | Species of Concern | Wherever found | |
| No common name | Cryptantha sobolifera | Resolved Taxon | Wherever found | |
| No common name | Cryptantha subcapitata | Species of Concern | Wherever found | |
| No common name | Cryptantha thompsonii | Resolved Taxon | Wherever found | |
| No common name | Cryptocarya mannii | Resolved Taxon | Wherever found | |
| No common name | Ctenium floridanum | Resolved Taxon | Wherever found | |
| No common name | Cucurbita texana | Resolved Taxon | Wherever found | |
| No common name | Cuphea aspera | Species of Concern | Wherever found | |
| No common name | Cyanea angustifolia lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Cyanea angustifolia racemosa | Resolved Taxon | Wherever found | |
| No common name | Cyanea arborea | Resolved Taxon | Wherever found | |
| No common name | Cyanea aspleniifolia | Resolved Taxon | Wherever found | |
| No common name | Cyanea comata | Resolved Taxon | Wherever found | |
| No common name | Cyanea giffardii | Resolved Taxon | Wherever found | |
| No common name | Cyanea grimesiana ssp. cylindrocalyx | Resolved Taxon | Wherever found | |
| No common name | Cyanea hirtella | Resolved Taxon | Wherever found | |
| No common name | Cyanea kauaulaensis | Endangered | Wherever found | 10-31-2016 |
| No common name | Cyanea linearifolia | Resolved Taxon | Wherever found | |
| No common name | Cyanea parvifolia | Resolved Taxon | Wherever found | |
| No common name | Cyanea pohaku | Resolved Taxon | Wherever found | |
| No common name | Cyanea pycnocarpa | Resolved Taxon | Wherever found | |
| No common name | Cyanea quercifolia | Resolved Taxon | Wherever found | |
| No common name | Cyanea scabra | Resolved Taxon | Wherever found | |
| No common name | Cyanea sessilifolia | Resolved Taxon | Wherever found | |
| No common name | Cyanecula svecica | Species of Concern | | |
| No common name | Cyclosorus boydiae kipahuluensis | Resolved Taxon | Wherever found | |
| No common name | Cyclosorus boydiae var. boydiae | Resolved Taxon | Wherever found | |
| No common name | Cymophyllus fraserianus | Resolved Taxon | Wherever found | |
| No common name | Cymopterus basalticus | Resolved Taxon | Wherever found | |
| No common name | Cymopterus corrugatus | Resolved Taxon | Wherever found | |
| No common name | Cymopterus davisii | Species of Concern | Wherever found | |
| No common name | Cymopterus douglassii | Species of Concern | Wherever found | |
| No common name | Cymopterus everetii | Resolved Taxon | Wherever found | |
| No common name | Cymopterus goodrichii | Species of Concern | Wherever found | |
| No common name | Cymopterus ibapensis | Resolved Taxon | Wherever found | |
| No common name | Cymopterus megacephalus | Species of Concern | Wherever found | |
| No common name | Cymopterus newberryi | Resolved Taxon | Wherever found | |
| No common name | Cymopterus nivalis | Resolved Taxon | Wherever found | |
| No common name | Cymopterus ripleyi saniculoides | Species of Concern | Wherever found | |
| No common name | Cymopterus rosei | Resolved Taxon | Wherever found | |
| No common name | Cynanchum monense | Resolved Taxon | Wherever found | |
| No common name | Cynanchum wigginsii | Species of Concern | Wherever found | |
| No common name | Cyperus cephalanthus | Resolved Taxon | Wherever found | |
| No common name | Cyperus fauriei | Endangered | Wherever found | 03-04-1994 |
| No common name | Cyperus granitophilus | Resolved Taxon | Wherever found | |
| No common name | Cyperus neokunthianus | Endangered | Wherever found | 10-31-2016 |
| No common name | Cyperus pennatiformis | Endangered | Wherever found | 11-10-1994 |
| No common name | Cyperus rockii | Species of Concern | Wherever found | |
| No common name | Cyrtandra alata | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra alnea | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra ambigua | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra axilliflora | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra basipartita | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra bryanii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra carinata | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra caudatisepala | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra christophersenii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra conradtii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra cordifolia brevipilita | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra cordifolia gynoglabra | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra crassior | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra cupuliformis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra elliptisepala | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra ferricolorata | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra ferruginosa | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra forbesii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra garnotiana | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra georgiana | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra grayana lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra grayi | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra hawaiensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra hirsutula | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra honolulensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra hosakae | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra intrapilosa | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra kaalae | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra kahanensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra kalichii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra kohalae | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra laevis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra laxiflora | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra lessoniana angustifolia | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra lessoniana intrapubens | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra longifolia longifolia | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra longiloba | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra lysiosepala grayi | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra lysiosepala haleakalensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra lysiosepala lysiosepala | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra malacophylla malacophylla | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra mannii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra niuensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra olona | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra paludosa | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra paludosa haupuensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra platyphylla hiloensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra pubens | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra ramosissima | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra rivularis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra rockii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra scabrella | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra subintegra | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra turbiniformis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra vaniota | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra villicalyx pubentigyna | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X atomigyna | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X basipartita | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X crassifolia | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X ferruginosa | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X forbesii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X hillebrandii | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X honolulensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X hosakae | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X kipapaensis | Resolved Taxon | Wherever found | |
| No common name | Cyrtandra X rockii | Resolved Taxon | Wherever found | |
| No common name | Daedalochila scintilla | Resolved Taxon | Wherever found | |
| No common name | Dalea gattingeri | Resolved Taxon | Wherever found | |
| No common name | Dallia pectoralis | Not Listed | | |
| No common name | Daphnopsis helleriana | Endangered | Wherever found | 06-23-1988 |
| No common name | Dasynotus daubenmirei | Resolved Taxon | Wherever found | |
| No common name | Delissea fallax | Resolved Taxon | Wherever found | |
| No common name | Delissea laciniata | Resolved Taxon | Wherever found | |
| No common name | Delissea lauliiana | Resolved Taxon | Wherever found | |
| No common name | Delissea parviflora | Resolved Taxon | Wherever found | |
| No common name | Delissea rhytidosperma | Endangered | Wherever found | 02-25-1994 |
| No common name | Delissea sinuata | Resolved Taxon | Wherever found | |
| No common name | Delissea undulata | Endangered | Wherever found | 10-10-1996 |
| No common name | Dendrobium guamense | Threatened | Wherever found | 11-02-2015 |
| No common name | Dendrographa leucophaea | Species of Concern | Wherever found | |
| No common name | Dentaria incisa | Resolved Taxon | Wherever found | |
| No common name | Deparia kaalaana | Endangered | Wherever found | 10-31-2016 |
| No common name | Descurainia torulosa | Resolved Taxon | Wherever found | |
| No common name | Dichanthelium aciculare var. aciculare | Species of Concern | Wherever found | |
| No common name | Dichanthelium nudicaule | Species of Concern | Wherever found | |
| No common name | Dicliptera krugii | Species of Concern | Wherever found | |
| No common name | Didymodon anserinocapitatus | Resolved Taxon | Wherever found | |
| No common name | Digitaria floridana | Species of Concern | Wherever found | |
| No common name | Digitaria gracillima | Species of Concern | Wherever found | |
| No common name | Diplazium molokaiense | Endangered | Wherever found | 09-26-1994 |
| No common name | Dissochondrus biflorus | Resolved Taxon | Wherever found | |
| No common name | Ditaxis cyanophylla | Resolved Taxon | Wherever found | |
| No common name | Dodecatheon poeticum | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa costulata | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa forbesii | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa molokaiensis | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa oblonga | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa pallida | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa skottsbergii | Resolved Taxon | Wherever found | |
| No common name | Dodonaea eriocarpa varians | Resolved Taxon | Wherever found | |
| No common name | Dodonaea sandwicensis latifolia | Resolved Taxon | Wherever found | |
| No common name | Dodonaea sandwicensis simulans | Resolved Taxon | Wherever found | |
| No common name | Dodonaea stenoptera fauriei | Resolved Taxon | Wherever found | |
| No common name | Dodonaea stenoptera stenoptera | Resolved Taxon | Wherever found | |
| No common name | Doryopteris angelica | Endangered | Wherever found | 05-13-2010 |
| No common name | Doryopteris takeuchii | Endangered | Wherever found | 10-18-2012 |
| No common name | Douglasia idahoensis | Species of Concern | Wherever found | |
| No common name | Douglasia laevigata laevigata | Resolved Taxon | Wherever found | |
| No common name | Douglasia nivalis nivalis | Resolved Taxon | Wherever found | |
| No common name | Draba apiculata daviesiae | Resolved Taxon | Wherever found | |
| No common name | Draba aprica | Resolved Taxon | Wherever found | |
| No common name | Draba argyraea | Resolved Taxon | Wherever found | |
| No common name | Draba arida | Species of Concern | Wherever found | |
| No common name | Draba asprella asprella | Resolved Taxon | Wherever found | |
| No common name | Draba asprella kaibabensis | Resolved Taxon | Wherever found | |
| No common name | Draba asprella stelligera | Resolved Taxon | Wherever found | |
| No common name | Draba jaegeri | Species of Concern | Wherever found | |
| No common name | Draba kassii | Resolved Taxon | Wherever found | |
| No common name | Draba lemmonii cyclomorpha | Resolved Taxon | Wherever found | |
| No common name | Draba maguirei burkei | Resolved Taxon | Wherever found | |
| No common name | Draba maguirei maguirei | Resolved Taxon | Wherever found | |
| No common name | Draba mogollonica | Resolved Taxon | Wherever found | |
| No common name | Draba murrayi | Species of Concern | Wherever found | |
| No common name | Draba oreibata serpentina | Species of Concern | Wherever found | |
| No common name | Draba paucifructa | Species of Concern | Wherever found | |
| No common name | Draba pectinipila | Species of Concern | Wherever found | |
| No common name | Draba ruaxes | Resolved Taxon | Wherever found | |
| No common name | Draba smithii | Species of Concern | Wherever found | |
| No common name | Draba sphaeroides cusickii | Resolved Taxon | Wherever found | |
| No common name | Draba yukonensis | Species of Concern | Wherever found | |
| No common name | Dracontium polyphyllum | Species of Concern | Wherever found | |
| No common name | Dryopteris takeuchii | Status Undefined | Wherever found | |
| No common name | Dubautia knudsenii degeneri | Resolved Taxon | Wherever found | |
| No common name | Dubautia laevigata parvifolia | Resolved Taxon | Wherever found | |
| No common name | Dubautia laxa blakei | Resolved Taxon | Wherever found | |
| No common name | Dubautia linearis ssp. hillebrandii | Resolved Taxon | Wherever found | |
| No common name | Dubautia magnifolia | Resolved Taxon | Wherever found | |
| No common name | Dubautia molokaiensis | Resolved Taxon | Wherever found | |
| No common name | Dubautia montana robustior | Resolved Taxon | Wherever found | |
| No common name | Dubautia plantaginea acridentata | Resolved Taxon | Wherever found | |
| No common name | Dubautia plantaginea plantaginea | Resolved Taxon | Wherever found | |
| No common name | Dubautia platyphylla leptophylla | Resolved Taxon | Wherever found | |
| No common name | Dubautia reticulata | Resolved Taxon | Wherever found | |
| No common name | Dubautia thyrsiflora cernua | Resolved Taxon | Wherever found | |
| No common name | Dubautia thyrsiflora thyrsiflora | Resolved Taxon | Wherever found | |
| No common name | Dubautia X fallax | Resolved Taxon | Wherever found | |
| No common name | Dubautia X thyrsiflora | Resolved Taxon | Wherever found | |
| No common name | Dudleya saxosa collomiae | Resolved Taxon | Wherever found | |
| No common name | Dyschoriste crenulata | Resolved Taxon | Wherever found | |
| No common name | echeandia texensis | Resolved Taxon | Wherever found | |
| No common name | Echinocereus ledingii | Resolved Taxon | Wherever found | |
| No common name | Echinodorus tenellus | Species of Concern | Wherever found | |
| No common name | Echinomastus erectocentrus erectocentrus | Species of Concern | Wherever found | |
| No common name | eidmannella bullata | Resolved Taxon | Wherever found | |
| No common name | eidmannella delicata | Resolved Taxon | Wherever found | |
| No common name | eidmannella nasuta | Resolved Taxon | Wherever found | |
| No common name | eidmannella reclusa | Resolved Taxon | Wherever found | |
| No common name | Elaphoglossum serpens | Endangered | Wherever found | 06-09-1993 |
| No common name | Eleocharis austrotexana | Resolved Taxon | Wherever found | |
| No common name | Eleocharis wolfii | Species of Concern | Wherever found | |
| No common name | Elymus svensonii | Species of Concern | Wherever found | |
| No common name | Elytraria caroliniensis caroliniensis | Resolved Taxon | Wherever found | |
| No common name | Embelia pacifica | Resolved Taxon | Wherever found | |
| No common name | Encelia frutescens resinosa | Resolved Taxon | Wherever found | |
| No common name | Encyclia kranzlinii | Species of Concern | Wherever found | |
| No common name | Encyclia oncidioides | Resolved Taxon | Wherever found | |
| No common name | Ephemerella apopsis | Resolved Taxon | Wherever found | |
| No common name | Epidendrum brittonianum | Resolved Taxon | Wherever found | |
| No common name | Epidendrum lacerum | Resolved Taxon | Wherever found | |
| No common name | Eragrostis deflexa | Resolved Taxon | Wherever found | |
| No common name | Eragrostis leptostachya | Species of Concern | Wherever found | |
| No common name | Eragrostis paupera | Resolved Taxon | Wherever found | |
| No common name | Ericameria cervina | Resolved Taxon | Wherever found | |
| No common name | Ericameria crispa | Species of Concern | Wherever found | |
| No common name | Ericameria nauseosa var. iridis | Species of Concern | Wherever found | |
| No common name | Ericameria watsonii | Resolved Taxon | Wherever found | |
| No common name | Ericameria zionis | Species of Concern | Wherever found | |
| No common name | Erigeron arenarioides | Resolved Taxon | Wherever found | |
| No common name | Erigeron arizonicus | Resolved Taxon | Wherever found | |
| No common name | Erigeron bigelovii | Resolved Taxon | Wherever found | |
| No common name | Erigeron canaanii | Species of Concern | Wherever found | |
| No common name | Erigeron carringtonae | Species of Concern | Wherever found | |
| No common name | Erigeron chrysopsidis brevifolius | Resolved Taxon | Wherever found | |
| No common name | Erigeron flettii | Resolved Taxon | Wherever found | |
| No common name | Erigeron garrettii | Resolved Taxon | Wherever found | |
| No common name | Erigeron huberi | Resolved Taxon | Wherever found | |
| No common name | Erigeron hultenii | Resolved Taxon | Wherever found | |
| No common name | Erigeron lackshewitz | Species of Concern | Wherever found | |
| No common name | Erigeron leibergii | Resolved Taxon | Wherever found | |
| No common name | Erigeron lobatus | Resolved Taxon | Wherever found | |
| No common name | Erigeron maguirei harrisonii | Species of Concern | Wherever found | |
| No common name | Erigeron muirii | Resolved Taxon | Wherever found | |
| No common name | Erigeron ovinus | Species of Concern | Wherever found | |
| No common name | Erigeron perglaber | Resolved Taxon | Wherever found | |
| No common name | Erigeron piperanus | Resolved Taxon | Wherever found | |
| No common name | Erigeron pringlei | Resolved Taxon | Wherever found | |
| No common name | Erigeron pulchellus tolsteadii | Species of Concern | Wherever found | |
| No common name | Erigeron salmonensis | Species of Concern | Wherever found | |
| No common name | Erigeron sionis | Species of Concern | Wherever found | |
| No common name | Erigeron sivinskii | Species of Concern | Wherever found | |
| No common name | Erigeron uncialis conjugans | Resolved Taxon | Wherever found | |
| No common name | Erigeron untermannii | Species of Concern | Wherever found | |
| No common name | Erigeron wilkenii | Resolved Taxon | Wherever found | |
| No common name | Erigeron zothecinus | Resolved Taxon | Wherever found | |
| No common name | Eriochloa michauxii simpsonii | Species of Concern | Wherever found | |
| No common name | Eriogonum allenii | Resolved Taxon | Wherever found | |
| No common name | Eriogonum concinnum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum correllii | Resolved Taxon | Wherever found | |
| No common name | Eriogonum grayi | Resolved Taxon | Wherever found | |
| No common name | Eriogonum heermannii subracemosum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum lagopus | Species of Concern | Wherever found | |
| No common name | Eriogonum latens | Resolved Taxon | Wherever found | |
| No common name | Eriogonum lewisii | Species of Concern | Wherever found | |
| No common name | Eriogonum lobbii robustum | Species of Concern | Wherever found | |
| No common name | Eriogonum longifolium harperi | Species of Concern | Wherever found | |
| No common name | Eriogonum natum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum novonudum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum nummulare | Resolved Taxon | Wherever found | |
| No common name | Eriogonum ovalifolium caelestinum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum phoeniceum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum polycladon | Resolved Taxon | Wherever found | |
| No common name | Eriogonum rubricaule | Resolved Taxon | Wherever found | |
| No common name | Eriogonum scopulorum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum thymoides | Resolved Taxon | Wherever found | |
| No common name | Eriogonum tumulosum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum umbellatum hypoleium | Resolved Taxon | Wherever found | |
| No common name | Eriogonum viridulum | Resolved Taxon | Wherever found | |
| No common name | Eriogonum visheri | Species of Concern | Wherever found | |
| No common name | Erithalis fruticosa | Species of Concern | Wherever found | |
| No common name | Errazurizia rotundata | Resolved Taxon | Wherever found | |
| No common name | Erythronium cliftonii | Resolved Taxon | Wherever found | |
| No common name | Erythronium elegans | Species of Concern | Wherever found | |
| No common name | Erythronium grandiflorum nudipetalum | Resolved Taxon | Wherever found | |
| No common name | Erythronium helenae | Resolved Taxon | Wherever found | |
| No common name | Erythronium oregonum | Resolved Taxon | Wherever found | |
| No common name | Eschscholzia multiflora twisselmannii | Species of Concern | Wherever found | |
| No common name | Euchloe ausonides ssp. ausonides | Not Listed | | |
| No common name | Eugenia bellonis | Species of Concern | Wherever found | |
| No common name | Eugenia bryanii | Endangered | Wherever found | 11-02-2015 |
| No common name | Eugenia margarettae | Species of Concern | Wherever found | |
| No common name | Eugenia underwoodii | Species of Concern | Wherever found | |
| No common name | Eugenia woodburyana | Threatened | Wherever found | 09-09-1994 |
| No common name | euhyparpax rosea | Resolved Taxon | Wherever found | |
| No common name | Eupatorium altissimum | Resolved Taxon | Wherever found | |
| No common name | Euphorbia austrina | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides halawana | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides haupuana | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides humbertii | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides kohalana | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides nelsonii | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides nematopoda | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides saxicola | Resolved Taxon | Wherever found | |
| No common name | Euphorbia celastroides waikoluensis | Resolved Taxon | Wherever found | |
| No common name | Euphorbia degeneri molokaiensis | Resolved Taxon | Wherever found | |
| No common name | Euphorbia discoidalis | Resolved Taxon | Wherever found | |
| No common name | Euphorbia exserta | Resolved Taxon | Wherever found | |
| No common name | Euphorbia innocua | Resolved Taxon | Wherever found | |
| No common name | Euphorbia macropus | Species of Concern | Wherever found | |
| No common name | Euphorbia roemeriana | Resolved Taxon | Wherever found | |
| No common name | Euphorbia strictior | Resolved Taxon | Wherever found | |
| No common name | Euphyllia cristata | Status Undefined | Wherever found | |
| No common name | Euphyllia paradivisa | Threatened | Wherever found | 11-13-2014 |
| No common name | Euphyllia paraencora | Status Undefined | Wherever found | |
| No common name | Eurhychium pringlei | Species of Concern | Wherever found | |
| No common name | Eurya sandwicensis | Species of Concern | Wherever found | |
| No common name | Eurytaenia hinckleyi | Resolved Taxon | Wherever found | |
| No common name | Exocarpos gaudichaudii | Species of Concern | Wherever found | |
| No common name | Ferocactus eastwoodiae | Resolved Taxon | Wherever found | |
| No common name | Festuca hallii | Resolved Taxon | Wherever found | |
| No common name | Festuca hawaiiensis | Endangered | Wherever found | 10-31-2016 |
| No common name | Festuca molokaiensis | Endangered | Wherever found | 06-27-2013 |
| No common name | Ficedula albicilla | Species of Concern | | |
| No common name | Fimbristylis hawaiiensis | Species of Concern | Wherever found | |
| No common name | Flyriella parryi | Resolved Taxon | Wherever found | |
| No common name | Forchhammeria polyandra | Species of Concern | Wherever found | |
| No common name | Forestiera segregata pinetorum | Species of Concern | Wherever found | |
| No common name | Frasera coloradensis | Species of Concern | Wherever found | |
| No common name | Frasera idahoensis | Resolved Taxon | Wherever found | |
| No common name | Frasera puberulenta | Resolved Taxon | Wherever found | |
| No common name | Frasera tubulosa | Resolved Taxon | Wherever found | |
| No common name | Fumontana deprehendor | Species of Concern | | |
| No common name | Gahnia lanaiensis | Original Data in Error - Taxonomic Revision | Wherever found | 09-20-1991 |
| No common name | Galactia eggersii | Species of Concern | Wherever found | |
| No common name | Galinsoga semicalva percalva | Resolved Taxon | Wherever found | |
| No common name | Gallinula galeata | Species of Concern | | |
| No common name | Gardenia taitensis | Resolved Taxon | Wherever found | |
| No common name | Gaura demareei | Resolved Taxon | Wherever found | |
| No common name | Gentiana austromontana | Resolved Taxon | Wherever found | |
| No common name | Gentianella propinqua aleutica | Resolved Taxon | Wherever found | |
| No common name | Gentianella wislizenii | Species of Concern | Wherever found | |
| No common name | Geocarpon minimum | Threatened | Wherever found | 06-16-1987 |
| No common name | Gesneria pauciflora | Threatened | Wherever found | 03-07-1995 |
| No common name | Gilia mcvickerae | Resolved Taxon | Wherever found | |
| No common name | Gilia nyensis | Resolved Taxon | Wherever found | |
| No common name | Gilia pentstemonoides | Resolved Taxon | Wherever found | |
| No common name | Gilia ripleyi | Resolved Taxon | Wherever found | |
| No common name | Glandularia maritima | Species of Concern | Wherever found | |
| No common name | Gonocalyx concolor | Endangered | Wherever found | 10-09-2014 |
| No common name | Gouania hillebrandii | Endangered | Wherever found | 11-09-1984 |
| No common name | Gouania meyenii | Endangered | Wherever found | 10-29-1991 |
| No common name | Gouania vitifolia | Endangered | Wherever found | 06-27-1994 |
| No common name | Gouldia st-johnii munroi | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis bobeoides | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis congesta | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis crassicaulis | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis degeneri | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis lanai | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis parvifolia | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis pseudodichotoma | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis pubescens | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis quadrangularis | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis rotundifolia | Resolved Taxon | Wherever found | |
| No common name | Gouldia terminalis subcordata | Resolved Taxon | Wherever found | |
| No common name | Graptopetalum rusbyi | Resolved Taxon | Wherever found | |
| No common name | Gunnera petaloidea | Resolved Taxon | Wherever found | |
| No common name | Gutierrezia petradoria | Resolved Taxon | Wherever found | |
| No common name | Gutierrezia sarothrae | Resolved Taxon | Wherever found | |
| No common name | Gutierrezia sarothrae pomariensis | Resolved Taxon | Wherever found | |
| No common name | Gutierrezia wrightii | Resolved Taxon | Wherever found | |
| No common name | Gymnocarpium heterosporum | Resolved Taxon | Wherever found | |
| No common name | Gymnopogon chapmanianus | Resolved Taxon | Wherever found | |
| No common name | Hackelia hispida | Resolved Taxon | Wherever found | |
| No common name | Halimolobos perplexa lemhiensis | Resolved Taxon | Wherever found | |
| No common name | Halimolobos perplexa perplexa | Resolved Taxon | Wherever found | |
| No common name | Hapalocrex flaviventer | Species of Concern | | |
| No common name | Haplopappus carthamoides subsquarrosus | Species of Concern | Wherever found | |
| No common name | Haplopappus racemosus congestus | Resolved Taxon | Wherever found | |
| No common name | Haplopappus spinulosus laevis | Resolved Taxon | Wherever found | |
| No common name | Haplostachys bryanii | Resolved Taxon | Wherever found | |
| No common name | Haplostachys linearifolia | Resolved Taxon | Wherever found | |
| No common name | Haplostachys munroi | Resolved Taxon | Wherever found | |
| No common name | Haplostachys truncata | Resolved Taxon | Wherever found | |
| No common name | Hastingsia atropurpurea | Species of Concern | Wherever found | |
| No common name | Hastingsia bracteosa | Species of Concern | Wherever found | |
| No common name | Hazardia brickellioides | Resolved Taxon | Wherever found | |
| No common name | Hechtia texensis | Resolved Taxon | Wherever found | |
| No common name | Hedeoma dentatum | Resolved Taxon | Wherever found | |
| No common name | Hedeoma molle | Resolved Taxon | Wherever found | |
| No common name | Hedeoma nanum californicum | Resolved Taxon | Wherever found | |
| No common name | Hedeoma pulcherrimum | Resolved Taxon | Wherever found | |
| No common name | Hedyotis angusta angusta | Resolved Taxon | Wherever found | |
| No common name | Hedyotis elatior | Species of Concern | Wherever found | |
| No common name | Hedyotis foliosa | Resolved Taxon | Wherever found | |
| No common name | Hedyotis formosa | Species of Concern | Wherever found | |
| No common name | Hedyotis glaucifolia helleri | Resolved Taxon | Wherever found | |
| No common name | Hedyotis littoralis | Species of Concern | Wherever found | |
| No common name | Hedyotis remyi nuttallii | Resolved Taxon | Wherever found | |
| No common name | Hedyotis remyi plana | Resolved Taxon | Wherever found | |
| No common name | Hedyotis schlechtendahliana nuttallii | Resolved Taxon | Wherever found | |
| No common name | Hedyotis schlechtendahliana plana | Resolved Taxon | Wherever found | |
| No common name | Hedyotis schlechtendahliana reticulata | Resolved Taxon | Wherever found | |
| No common name | Hedyotis tryblium | Species of Concern | Wherever found | |
| No common name | Hedysarum boreale gremiale | Resolved Taxon | Wherever found | |
| No common name | Hedysarum occidentale canone | Species of Concern | Wherever found | |
| No common name | Helenium arizonicum | Resolved Taxon | Wherever found | |
| No common name | Helianthus carnosus | Species of Concern | Wherever found | |
| No common name | Helianthus deserticola | Resolved Taxon | Wherever found | |
| No common name | Helianthus glaucophyllus | Resolved Taxon | Wherever found | |
| No common name | Helianthus laciniatus crenatus | Resolved Taxon | Wherever found | |
| No common name | Helianthus porteri | Resolved Taxon | Wherever found | |
| No common name | Helianthus praetermissus | Resolved Taxon | Wherever found | |
| No common name | Helianthus smithii | Resolved Taxon | Wherever found | |
| No common name | Heliotropium polyphyllum horizontale | Resolved Taxon | Wherever found | |
| No common name | Hermidium alipes pallidum | Resolved Taxon | Wherever found | |
| No common name | Herricka horrida | Species of Concern | Wherever found | |
| No common name | Hesperocnide sandwicensis | Resolved Taxon | Wherever found | |
| No common name | Hesperomannia arborescens | Endangered | Wherever found | 03-28-1994 |
| No common name | Hesperomannia arbuscula | Endangered | Wherever found | 10-29-1991 |
| No common name | Hesperomannia lydgatei | Endangered | Wherever found | 09-20-1991 |
| No common name | Heterodermia erinacea | Species of Concern | Wherever found | |
| No common name | Heterotheca rutteri | Species of Concern | Wherever found | |
| No common name | Heuchera missouriensis | Resolved Taxon | Wherever found | |
| No common name | Heuchera villosa arkansana | Resolved Taxon | Wherever found | |
| No common name | Hexastylis contracta | Species of Concern | Wherever found | |
| No common name | Hibiscadelphus bombycinus | Resolved Taxon | Wherever found | |
| No common name | Hibiscadelphus wilderanus | Resolved Taxon | Wherever found | |
| No common name | Hibiscus waimeae waimeae | Resolved Taxon | Wherever found | |
| No common name | Hieracium longiberbe | Resolved Taxon | Wherever found | |
| No common name | Hierococcyx nisicolor | Species of Concern | | |
| No common name | Himatione fraithii | Species of Concern | | |
| No common name | Holocarpha virgata elongata | Species of Concern | Wherever found | |
| No common name | Holospira millestriata | Resolved Taxon | Wherever found | |
| No common name | Huperzia haleakalae | Resolved Taxon | Wherever found | |
| No common name | Hydrobates hornbyi | Species of Concern | | |
| No common name | Hydrobates monorhis | Species of Concern | | |
| No common name | Hydrobates socorroensis | Species of Concern | | |
| No common name | Hydrobates tethys | Species of Concern | | |
| No common name | Hydropsalis cayennensis | Species of Concern | | |
| No common name | Hydroptila abbotti | Resolved Taxon | Wherever found | |
| No common name | Hymenocallis latifolia | Resolved Taxon | Wherever found | |
| No common name | Hymenopappus filifolius idahoensis | Resolved Taxon | Wherever found | |
| No common name | Hymenoxys helenioides | Resolved Taxon | Wherever found | |
| No common name | Hymenoxys lapidicola | Resolved Taxon | Wherever found | |
| No common name | Hymenoxys quinquesquamata | Resolved Taxon | Wherever found | |
| No common name | Hymenoxys subintegra | Resolved Taxon | Wherever found | |
| No common name | Hypericum adpressum | Species of Concern | Wherever found | |
| No common name | Hypericum dolabriforme | Resolved Taxon | Wherever found | |
| No common name | ictalurus species | Status Undefined | Wherever found | |
| No common name | Icterus portoricensis | Species of Concern | | |
| No common name | Ilex opaca arenicola | Resolved Taxon | Wherever found | |
| No common name | Ilex sintenisii | Endangered | Wherever found | 04-22-1992 |
| No common name | Ionactis elegans | Species of Concern | Wherever found | |
| No common name | Ipomoea cairica lineariloba | Resolved Taxon | Wherever found | |
| No common name | Ipomoea cardiophylla | Resolved Taxon | Wherever found | |
| No common name | Ipomopsis aggregata webberi | Species of Concern | Wherever found | |
| No common name | Ipomopsis globularis | Resolved Taxon | Wherever found | |
| No common name | Ipomopsis spicata robruthii | Species of Concern | Wherever found | |
| No common name | Isoperla sagittata | Under Review | Wherever found | |
| No common name | Isopora crateriformis | Threatened | Wherever found | 11-13-2014 |
| No common name | Ivesia cryptocaulis | Species of Concern | Wherever found | |
| No common name | Ivesia jaegeri | Species of Concern | Wherever found | |
| No common name | Ivesia longibracteata | Species of Concern | Wherever found | |
| No common name | Ivesia multifoliolata | Resolved Taxon | Wherever found | |
| No common name | Ivesia shockleyi ostleri | Species of Concern | Wherever found | |
| No common name | Jamesia americana zionis | Species of Concern | Wherever found | |
| No common name | Jamesia tetrapetala | Species of Concern | Wherever found | |
| No common name | Jaquinia umbellata | Resolved Taxon | Wherever found | |
| No common name | Juncus mertensianus | Resolved Taxon | Wherever found | |
| No common name | Juncus trifidus carolinianus | Resolved Taxon | Wherever found | |
| No common name | Justicia borinquensis | Species of Concern | Wherever found | |
| No common name | Justicia culebritae | Species of Concern | Wherever found | |
| No common name | Justicia warnockii | Resolved Taxon | Wherever found | |
| No common name | Kadua degeneri | Endangered | Wherever found | 10-29-1991 |
| No common name | Kadua haupuensis | Endangered | Wherever found | 10-31-2016 |
| No common name | Kadua parvula | Endangered | Wherever found | 10-29-1991 |
| No common name | Kadua st.-johnii | Endangered | Wherever found | 09-30-1991 |
| No common name | Kalmiopsis leachiana | Resolved Taxon | Wherever found | |
| No common name | Keysseria (=Lagenifera) erici | Endangered | Wherever found | 05-13-2010 |
| No common name | Keysseria (=Lagenifera) helenae | Endangered | Wherever found | 05-13-2010 |
| No common name | Labordia decurrens decurrens | Resolved Taxon | Wherever found | |
| No common name | Labordia fagraeoidea longisepala | Resolved Taxon | Wherever found | |
| No common name | Labordia fagraeoidea saint-johniana | Resolved Taxon | Wherever found | |
| No common name | Labordia fagraeoidea waianaeana | Resolved Taxon | Wherever found | |
| No common name | Labordia hedyosmifolia kilaueana | Resolved Taxon | Wherever found | |
| No common name | Labordia hedyosmifolia magnifolia | Resolved Taxon | Wherever found | |
| No common name | Labordia hedyosmifolia robusta | Resolved Taxon | Wherever found | |
| No common name | Labordia hedyosmifolia rockii | Resolved Taxon | Wherever found | |
| No common name | Labordia hedyosmifolia skottsbergii | Resolved Taxon | Wherever found | |
| No common name | Labordia hirtella imbricata | Resolved Taxon | Wherever found | |
| No common name | Labordia hirtella laevis | Resolved Taxon | Wherever found | |
| No common name | Labordia hirtella laevisepala | Resolved Taxon | Wherever found | |
| No common name | Labordia hirtella microcalyx | Resolved Taxon | Wherever found | |
| No common name | Labordia hirtella microphylla | Resolved Taxon | Wherever found | |
| No common name | Labordia kaalae brachypoda | Resolved Taxon | Wherever found | |
| No common name | Labordia kaalae fosbergii | Resolved Taxon | Wherever found | |
| No common name | Labordia kaalae mendax | Resolved Taxon | Wherever found | |
| No common name | Labordia lorenciana | Endangered | Wherever found | 10-31-2016 |
| No common name | Labordia molokaiana molokaiana | Resolved Taxon | Wherever found | |
| No common name | Labordia molokaiana munroi | Resolved Taxon | Wherever found | |
| No common name | Labordia molokaiana setosa | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia euphorbioidea | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia forbesii | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia honolulensis | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia microgyna | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia parvifolia | Resolved Taxon | Wherever found | |
| No common name | Labordia tinifolia tenuifolia | Resolved Taxon | Wherever found | |
| No common name | Lachlania dencyannae | Resolved Taxon | Wherever found | |
| No common name | Lachnocaulon beyrichianum | Resolved Taxon | Wherever found | |
| No common name | Lantana depressa | Species of Concern | Wherever found | |
| No common name | Larvivora cyane | Species of Concern | | |
| No common name | Larvivora sibilans | Species of Concern | | |
| No common name | Lathyrus holochlorus | Resolved Taxon | Wherever found | |
| No common name | Leavenworthia exigua exigua | Resolved Taxon | Wherever found | |
| No common name | Leavenworthia stylosa | Resolved Taxon | Wherever found | |
| No common name | Lecanora masana | Species of Concern | | |
| No common name | Lecanora xanthosora | Species of Concern | Wherever found | |
| No common name | Lechea cernua | Resolved Taxon | Wherever found | |
| No common name | Lechea divaricata | Species of Concern | Wherever found | |
| No common name | Lechea lakelae | Species of Concern | Wherever found | |
| No common name | Lejeunea blomquistii | Species of Concern | Wherever found | |
| No common name | Lepanthes dodiana | Resolved Taxon | Wherever found | |
| No common name | Lepanthes eltoroensis | Recovery | Wherever found | 11-29-1991 |
| No common name | Lepidium montanum neeseae | Resolved Taxon | Wherever found | |
| No common name | Lepidium nanum | Resolved Taxon | Wherever found | |
| No common name | Lepidium orbiculare | Endangered | Wherever found | 10-31-2016 |
| No common name | Leptocereus grantianus | Endangered | Wherever found | 02-26-1993 |
| No common name | Leptodactylon glabrum | Species of Concern | Wherever found | |
| No common name | Leptodactylon pungens hazeliae | Species of Concern | Wherever found | |
| No common name | Lesquerella arctica scammanae | Resolved Taxon | Wherever found | |
| No common name | Lesquerella condensata | Resolved Taxon | Wherever found | |
| No common name | lesquerella navajoensis | Under Review | Wherever found | |
| No common name | Lessingia arachnoidea | Species of Concern | Wherever found | |
| No common name | Lessingia micradenia micradenia | Species of Concern | Wherever found | |
| No common name | Lewisia columbiana wallowensis | Resolved Taxon | Wherever found | |
| No common name | Lewisia cotyledon purdyi | Species of Concern | Wherever found | |
| No common name | Lewisia maguirei | Species of Concern | Wherever found | |
| No common name | Liatris cymosa | Resolved Taxon | Wherever found | |
| No common name | Ligusticum porteri brevilobum | Resolved Taxon | Wherever found | |
| No common name | Lilaeopsis carolinensis | Resolved Taxon | Wherever found | |
| No common name | Limbella fryei | Species of Concern | Wherever found | |
| No common name | Limnephilus adapus | Resolved Taxon | Wherever found | |
| No common name | Limonium limbatum | Resolved Taxon | Wherever found | |
| No common name | Linum sulcatum harperi | Species of Concern | Wherever found | |
| No common name | Lipochaeta heterophylla heterophylla | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta integrifolia argentea | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta lavarum conferta | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta lavarum hillebrandiana | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta lavarum maneleana | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta lavarum ovata | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta lavarum stearnsii | Resolved Taxon | Wherever found | |
| No common name | Lipochaeta ovata | Resolved Taxon | Wherever found | |
| No common name | Lobelia appendiculata gattingeri | Resolved Taxon | Wherever found | |
| No common name | Lobelia dunbariae | Species of Concern | Wherever found | |
| No common name | Lobelia hypoleuca rockii | Resolved Taxon | Wherever found | |
| No common name | Lobelia koolauensis | Endangered | Wherever found | 10-10-1996 |
| No common name | Lobelia monostachya | Endangered | Wherever found | 10-10-1996 |
| No common name | Lobelia niihauensis | Endangered | Wherever found | 10-29-1991 |
| No common name | Lobelia oahuensis | Endangered | Wherever found | 03-28-1994 |
| No common name | Lobelia remyi | Resolved Taxon | Wherever found | |
| No common name | Lomatium attenuatum | Resolved Taxon | Wherever found | |
| No common name | Lomatium cuspidatum | Resolved Taxon | Wherever found | |
| No common name | Lomatium hallii | Resolved Taxon | Wherever found | |
| No common name | Lomatium hendersonii | Resolved Taxon | Wherever found | |
| No common name | Lomatium laevigatum | Resolved Taxon | Wherever found | |
| No common name | Lomatium minimum | Resolved Taxon | Wherever found | |
| No common name | Lomatium oreganum | Resolved Taxon | Wherever found | |
| No common name | Lomatium quintuplex | Resolved Taxon | Wherever found | |
| No common name | Lomatium rollinsii | Resolved Taxon | Wherever found | |
| No common name | Lomatium serpentinum | Resolved Taxon | Wherever found | |
| No common name | Lomatium thompsonii | Resolved Taxon | Wherever found | |
| No common name | Lophocolea appalachiana | Species of Concern | Wherever found | |
| No common name | Lotus purshianus helleri | Species of Concern | Wherever found | |
| No common name | Loxops wolstenholmei | Species of Concern | | |
| No common name | Luina serpentina | Species of Concern | Wherever found | |
| No common name | Lunania ekmanii | Species of Concern | Wherever found | |
| No common name | Lupinus burkei caeruleomontanus | Resolved Taxon | Wherever found | |
| No common name | Lupinus crassus | Species of Concern | Wherever found | |
| No common name | Lupinus jonesii | Resolved Taxon | Wherever found | |
| No common name | Lupinus malacophyllus | Resolved Taxon | Wherever found | |
| No common name | Lupinus montigenus montigenus | Resolved Taxon | Wherever found | |
| No common name | Lupinus sabinii | Resolved Taxon | Wherever found | |
| No common name | Lupinus sericeus marianus | Resolved Taxon | Wherever found | |
| No common name | Luzula hawaiiensis oahuensis | Resolved Taxon | Wherever found | |
| No common name | Lygodesmia grandiflora stricta | Resolved Taxon | Wherever found | |
| No common name | Lyonia truncata var. proctorii | Endangered | Wherever found | 04-27-1993 |
| No common name | Lysiloma microphylla thornberi | Resolved Taxon | Wherever found | |
| No common name | Lysimachia filifolia | Endangered | Wherever found | 02-25-1994 |
| No common name | Lysimachia forbesii | Resolved Taxon | Wherever found | |
| No common name | Lysimachia iniki | Endangered | Wherever found | 05-13-2010 |
| No common name | Lysimachia kalalauensis | Species of Concern | Wherever found | |
| No common name | Lysimachia lydgatei | Endangered | Wherever found | 05-15-1992 |
| No common name | Lysimachia maxima | Endangered | Wherever found | 10-10-1996 |
| No common name | Lysimachia pendens | Endangered | Wherever found | 05-13-2010 |
| No common name | Lysimachia scopulensis | Endangered | Wherever found | 05-13-2010 |
| No common name | Lysimachia venosa | Endangered | Wherever found | 05-13-2010 |
| No common name | Lythrum ovalifolium | Resolved Taxon | Wherever found | |
| No common name | Machaeranthera grindelioides depressa | Resolved Taxon | Wherever found | |
| No common name | Machaeranthera gypsitherma | Resolved Taxon | Wherever found | |
| No common name | Machaeranthera laetevirens | Resolved Taxon | Wherever found | |
| No common name | Maesa walkeri | Threatened | Wherever found | 11-02-2015 |
| No common name | Malacothrix crispifolia | Species of Concern | Wherever found | |
| No common name | Malacothrix intermedia | Species of Concern | Wherever found | |
| No common name | Malvastrum hispidum | Resolved Taxon | Wherever found | |
| No common name | Mammillaria thornberi | Resolved Taxon | Wherever found | |
| No common name | Manfreda maculosa | Resolved Taxon | Wherever found | |
| No common name | Manihot davisiae | Resolved Taxon | Wherever found | |
| No common name | Mappia racemosa | Species of Concern | Wherever found | |
| No common name | Marsdenia elliptica | Species of Concern | Wherever found | |
| No common name | Marshallia ramosa | Species of Concern | Wherever found | |
| No common name | Matelea brevicoronata | Resolved Taxon | Wherever found | |
| No common name | Matelea floridana | Species of Concern | Wherever found | |
| No common name | Matelea parviflora | Resolved Taxon | Wherever found | |
| No common name | Maytenus cymosa | Resolved Taxon | Wherever found | |
| No common name | Melanitta stejneger | Species of Concern | | |
| No common name | Melanoplus alexanderi | Resolved Taxon | Wherever found | |
| No common name | Melanoplus chiricahuae | Resolved Taxon | Wherever found | |
| No common name | Melanoplus missoulae | Resolved Taxon | Wherever found | |
| No common name | Melanoplus pinaleno | Resolved Taxon | Wherever found | |
| No common name | melanoplus speciesfiftytwo | Status Undefined | Wherever found | |
| No common name | melanoplus speciesforty-eight | Status Undefined | Wherever found | |
| No common name | Melanoplus speciesforty-nine | Under Review | Wherever found | |
| No common name | Melanoplus speciesforty-seven | Under Review | Wherever found | |
| No common name | Melanoplus speciesforty-two | Under Review | Wherever found | |
| No common name | Melanoplus speciesfourty | Under Review | Wherever found | |
| No common name | Melanoplus speciesfourty-one | Under Review | Wherever found | |
| No common name | melanoplus speciesnine | Status Undefined | Wherever found | |
| No common name | Melanoplus speciesone | Under Review | Wherever found | |
| No common name | melanoplus speciessixtytwo | Status Undefined | Wherever found | |
| No common name | melanoplus speciesthirtysix | Status Undefined | Wherever found | |
| No common name | melanoplus speciestwentysix | Status Undefined | Wherever found | |
| No common name | melanoplus speciestwentytwo | Status Undefined | Wherever found | |
| No common name | Melanospiza bicolor | Species of Concern | | |
| No common name | Melanthera integrifolia | Resolved Taxon | Wherever found | |
| No common name | Melanthera parvifolia | Species of Concern | Wherever found | |
| No common name | Melicope clusiifolia | Resolved Taxon | Wherever found | |
| No common name | Melicope cornuta var. cornuta | Endangered | Wherever found | 10-18-2012 |
| No common name | Melicope cornuta var. decurrens | Endangered | Wherever found | 10-18-2012 |
| No common name | Melicope pseudoanisata | Resolved Taxon | Wherever found | |
| No common name | Melicope remyi | Endangered | Wherever found | 11-29-2013 |
| No common name | Melicope wawraeana | Resolved Taxon | Wherever found | |
| No common name | Melopyrrha portoricensis | Species of Concern | | |
| No common name | Mentzelia multicaulis var. librina | Species of Concern | Wherever found | |
| No common name | Mentzelia shultziorum | Resolved Taxon | Wherever found | |
| No common name | Mesadenus portoricensis | Resolved Taxon | Wherever found | |
| No common name | Metrosideros collina newellii | Resolved Taxon | Wherever found | |
| No common name | mexichthonius exoticus | Resolved Taxon | Wherever found | |
| No common name | Micarea ternaria | Resolved Taxon | Wherever found | |
| No common name | Microlepia strigosa var. mauiensis | Endangered | Wherever found | 10-31-2016 |
| No common name | Microseris howellii | Species of Concern | Wherever found | |
| No common name | Microseris laciniata detlingii | Species of Concern | Wherever found | |
| No common name | Microseris nutans siskiyouensis | Resolved Taxon | Wherever found | |
| No common name | Millepora foveolata | Status Undefined | Wherever found | |
| No common name | Millepora tuberosa | Status Undefined | Wherever found | |
| No common name | Mimulus hymenophyllus | Species of Concern | Wherever found | |
| No common name | Mimulus jungermannioides | Species of Concern | Wherever found | |
| No common name | Mimulus washoensis | Resolved Taxon | Wherever found | |
| No common name | Minuartia marcescens | Species of Concern | Wherever found | |
| No common name | Minuartia uniflora | Resolved Taxon | Wherever found | |
| No common name | Mitracarpus maxwelliae | Endangered | Wherever found | 09-09-1994 |
| No common name | Mitracarpus polycladus | Threatened | Wherever found | 09-09-1994 |
| No common name | Monardella diaboli | Resolved Taxon | Wherever found | |
| No common name | Montia bostockii | Resolved Taxon | Wherever found | |
| No common name | Montipora angulata | Status Undefined | Wherever found | |
| No common name | Montipora australiensis | Threatened | Wherever found | 11-13-2014 |
| No common name | Montipora calcarea | Status Undefined | Wherever found | |
| No common name | Montipora caliculata | Status Undefined | Wherever found | |
| No common name | Montipora lobulata | Status Undefined | Wherever found | |
| No common name | Montipora turgescens | Status Undefined | Wherever found | |
| No common name | Montipora verrilli | Status Undefined | Wherever found | |
| No common name | Muhlenbergia pilosa | Resolved Taxon | Wherever found | |
| No common name | Musineon lineare | Resolved Taxon | Wherever found | |
| No common name | Myotis melanorhinus | Species of Concern | | |
| No common name | Myrcia paganii | Endangered | Wherever found | 02-18-1994 |
| No common name | Myriophyllum laxum | Species of Concern | Wherever found | |
| No common name | Nama retrorsum | Resolved Taxon | Wherever found | |
| No common name | Nama xylopodum | Resolved Taxon | Wherever found | |
| No common name | Napaea dioica | Resolved Taxon | Wherever found | |
| No common name | neoallochernes incertus | Resolved Taxon | Wherever found | |
| No common name | neoleptoneta anopica | Resolved Taxon | Wherever found | |
| No common name | neoleptoneta concinna | Resolved Taxon | Wherever found | |
| No common name | neoleptoneta devia | Resolved Taxon | Wherever found | |
| No common name | neoleptoneta valverde | Resolved Taxon | Wherever found | |
| No common name | Neoparrya lithophila | Resolved Taxon | Wherever found | |
| No common name | Neotrichia downsi | Resolved Taxon | Wherever found | |
| No common name | Neotrichia juani | Resolved Taxon | Wherever found | |
| No common name | Neotrichia sonora | Resolved Taxon | Wherever found | |
| No common name | Neraudia angulata | Endangered | Wherever found | 10-29-1991 |
| No common name | Neraudia kauaiensis | Resolved Taxon | Wherever found | |
| No common name | Neraudia ovata | Endangered | Wherever found | 10-10-1996 |
| No common name | Neraudia sericea | Endangered | Wherever found | 11-10-1994 |
| No common name | Nervilia jacksoniae | Threatened | Wherever found | 11-02-2015 |
| No common name | Nesogenes rotensis | Endangered | Wherever found | 04-08-2004 |
| No common name | Nesophlox evelynae | Species of Concern | | |
| No common name | Nestronia umbellula | Resolved Taxon | Wherever found | |
| No common name | Neviusia alabamensis | Species of Concern | Wherever found | |
| No common name | Ninox japonica | Species of Concern | | |
| No common name | Notholaena schaffneri | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense decipiens | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense dubium | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense forbesii | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense helleri | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense kolekolense | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense lanaiense | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense lanceolatum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense latifolium | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense leptopodum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense longespicatum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense macrophyllum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense mauiense | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense niihauense | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense olokeleanum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense pulchelloides | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense pulchellum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense subcordatum | Resolved Taxon | Wherever found | |
| No common name | Nototrichium sandwicense syringifolium | Resolved Taxon | Wherever found | |
| No common name | Nototrichium viride | Resolved Taxon | Wherever found | |
| No common name | Nuphar luteum ulvaceum | Species of Concern | Wherever found | |
| No common name | Obovaria cf. unicolor | Proposed Threatened | | |
| No common name | Ochrosia compta | Resolved Taxon | Wherever found | |
| No common name | Omphalora arizonica | Resolved Taxon | Wherever found | |
| No common name | Oncopodura cruciata | Resolved Taxon | Wherever found | |
| No common name | Oncopodura prietoi | Resolved Taxon | Wherever found | |
| No common name | Onosmodium helleri | Resolved Taxon | Wherever found | |
| No common name | Onosmodium molle molle | Resolved Taxon | Wherever found | |
| No common name | Ophioglossum nudicaule | Resolved Taxon | Wherever found | |
| No common name | Opuntia basilaris longiareolata | Resolved Taxon | Wherever found | |
| No common name | Opuntia basilaris woodburyi | Resolved Taxon | Wherever found | |
| No common name | Opuntia heacockul | Species of Concern | Wherever found | |
| No common name | Opuntia phaeacantha flavispina | Resolved Taxon | Wherever found | |
| No common name | Opuntia phaeacantha mojavensis | Resolved Taxon | Wherever found | |
| No common name | Opuntia phaeacantha superbospina | Resolved Taxon | Wherever found | |
| No common name | Opuntia spinosissima | Species of Concern | Wherever found | |
| No common name | Opuntia triacantha | Resolved Taxon | Wherever found | |
| No common name | Oreothlypis superciliosa | Species of Concern | | |
| No common name | Oreoxis trotteri | Resolved Taxon | Wherever found | |
| No common name | Osmoxylon mariannense | Endangered | Wherever found | 04-08-2004 |
| No common name | Oxypolis ternata | Species of Concern | Wherever found | |
| No common name | Oxytheca watsonii | Resolved Taxon | Wherever found | |
| No common name | Oxytropis besseyi obnapiformis | Resolved Taxon | Wherever found | |
| No common name | Oxytropis campestris johannensis | Resolved Taxon | Wherever found | |
| No common name | Oxytropis campestris wanapum | Species of Concern | Wherever found | |
| No common name | Oxytropis glaberrima | Resolved Taxon | Wherever found | |
| No common name | Oxytropis sordida barnebyana | Species of Concern | Wherever found | |
| No common name | Ozobryum ogalalense | Resolved Taxon | Wherever found | |
| No common name | Pachyseris rugosa | Status Undefined | Wherever found | |
| No common name | Packera cardamine | Resolved Taxon | Wherever found | |
| No common name | Packera hesperia | Species of Concern | Wherever found | |
| No common name | Panicum stevensianum | Species of Concern | Wherever found | |
| No common name | Pantosteus discobolus | Not Listed | | |
| No common name | Papaver pygmaeum | Species of Concern | Wherever found | |
| No common name | Paronychia drummondii parviflora | Resolved Taxon | Wherever found | |
| No common name | Paronychia virginica parksii | Resolved Taxon | Wherever found | |
| No common name | Parrya nudicaulis | Resolved Taxon | Wherever found | |
| No common name | Parthenium alpinum | Resolved Taxon | Wherever found | |
| No common name | Passiflora berteroana | Species of Concern | Wherever found | |
| No common name | Passiflora bilobata | Species of Concern | Wherever found | |
| No common name | Passiflora murucuja | Resolved Taxon | Wherever found | |
| No common name | Pavona diffluens | Threatened | Wherever found | 11-13-2014 |
| No common name | Paxistima canbyi | Species of Concern | Wherever found | |
| No common name | Pectinia alcicornis | Status Undefined | Wherever found | |
| No common name | Pedicularis rainierensis | Resolved Taxon | Wherever found | |
| No common name | Pedicularis semibarbata charlestonensis | Species of Concern | Wherever found | |
| No common name | Pediomelum aromaticum tuhyi | Species of Concern | Wherever found | |
| No common name | Pediomelum pariensis | Species of Concern | Wherever found | |
| No common name | Pelea anisata haupuana | Resolved Taxon | Wherever found | |
| No common name | Pelea clusiaefolia pickeringii | Resolved Taxon | Wherever found | |
| No common name | Pelea elliptica mauiensis | Resolved Taxon | Wherever found | |
| No common name | Pelea grandifolia lianoides | Resolved Taxon | Wherever found | |
| No common name | Pelea grandifolia montana | Resolved Taxon | Wherever found | |
| No common name | Pelea grandifolia ovalifolia | Resolved Taxon | Wherever found | |
| No common name | Pelea parvifolia sessilis | Resolved Taxon | Wherever found | |
| No common name | Pelea peduncularis cordata | Resolved Taxon | Wherever found | |
| No common name | Pelea peduncularis niuensis | Resolved Taxon | Wherever found | |
| No common name | Pelea peduncularis nummularia | Resolved Taxon | Wherever found | |
| No common name | Pelea volcanica kohalae | Resolved Taxon | Wherever found | |
| No common name | Peniocereus greggii transmontanus | Resolved Taxon | Wherever found | |
| No common name | Penstemon ammophilum | Species of Concern | Wherever found | |
| No common name | Penstemon angustifolius vernalensis | Resolved Taxon | Wherever found | |
| No common name | Penstemon arenarius | Species of Concern | Wherever found | |
| No common name | Penstemon arkansanus | Resolved Taxon | Wherever found | |
| No common name | Penstemon atwoodii | Resolved Taxon | Wherever found | |
| No common name | Penstemon baccharifolius | Resolved Taxon | Wherever found | |
| No common name | Penstemon barrettiae | Species of Concern | Wherever found | |
| No common name | Penstemon bicolor bicolor | Species of Concern | Wherever found | |
| No common name | Penstemon bicolor roseus | Species of Concern | Wherever found | |
| No common name | Penstemon cobaea purpureus | Resolved Taxon | Wherever found | |
| No common name | Penstemon crandallii atractus | Species of Concern | Wherever found | |
| No common name | Penstemon dissectus | Resolved Taxon | Wherever found | |
| No common name | Penstemon elegantulus | Resolved Taxon | Wherever found | |
| No common name | Penstemon floribundus | Species of Concern | Wherever found | |
| No common name | Penstemon flowersii | Resolved Taxon | Wherever found | |
| No common name | Penstemon francisci-pennellii | Resolved Taxon | Wherever found | |
| No common name | Penstemon goodrichii | Species of Concern | Wherever found | |
| No common name | Penstemon humilis brevifolius | Resolved Taxon | Wherever found | |
| No common name | Penstemon humilis obtusifolius | Resolved Taxon | Wherever found | |
| No common name | Penstemon leptanthus | Species of Concern | Wherever found | |
| No common name | Penstemon moriahensis | Resolved Taxon | Wherever found | |
| No common name | Penstemon navajoa | Resolved Taxon | Wherever found | |
| No common name | Penstemon parviflorus | Species of Concern | Wherever found | |
| No common name | Penstemon patricus | Resolved Taxon | Wherever found | |
| No common name | Penstemon peckii | Species of Concern | Wherever found | |
| No common name | Penstemon procerus modestus | Resolved Taxon | Wherever found | |
| No common name | Penstemon pudicus | Species of Concern | Wherever found | |
| No common name | Penstemon thompsoniae jaegeri | Resolved Taxon | Wherever found | |
| No common name | Penstemon thurberi anestius | Resolved Taxon | Wherever found | |
| No common name | Penstemon virgatus pseudoputus | Resolved Taxon | Wherever found | |
| No common name | Penstemon washingtonensis | Resolved Taxon | Wherever found | |
| No common name | Penstemon yampaensis | Resolved Taxon | Wherever found | |
| No common name | Peperomia cookiana minutilimba | Resolved Taxon | Wherever found | |
| No common name | Peperomia degeneri | Species of Concern | Wherever found | |
| No common name | Peperomia expallescens brevipilosa | Resolved Taxon | Wherever found | |
| No common name | Peperomia fauriei | Resolved Taxon | Wherever found | |
| No common name | Peperomia helleri knudsenii | Resolved Taxon | Wherever found | |
| No common name | Peperomia lilifolia obtusata | Resolved Taxon | Wherever found | |
| No common name | Peperomia megalopoda | Species of Concern | Wherever found | |
| No common name | Peperomia myrtifolia | Resolved Taxon | Wherever found | |
| No common name | Peperomia oahuensis st-johnii | Resolved Taxon | Wherever found | |
| No common name | Peperomia obtusifolia | Resolved Taxon | Wherever found | |
| No common name | Peperomia rigidilimba | Resolved Taxon | Wherever found | |
| No common name | Peperomia rockii | Species of Concern | Wherever found | |
| No common name | Percina cf nasuta (Arkansas River basin) | Under Review | | |
| No common name | Percina cf nasuta (upper White River basin) | Under Review | | |
| No common name | Percina nigrofasciata | Not Listed | | |
| No common name | Percina sciera | Not Listed | | |
| No common name | Perityle lemmonii | Resolved Taxon | Wherever found | |
| No common name | Perityle megalocephala intricata | Resolved Taxon | Wherever found | |
| No common name | Perityle parryi | Resolved Taxon | Wherever found | |
| No common name | Perityle specuicola | Resolved Taxon | Wherever found | |
| No common name | Perityle staurophylla | Resolved Taxon | Wherever found | |
| No common name | Persea borbonia humilis | Resolved Taxon | Wherever found | |
| No common name | Peteria thompsonae | Resolved Taxon | Wherever found | |
| No common name | Petrophytum hendersonii | Resolved Taxon | Wherever found | |
| No common name | Phacelia constancei | Resolved Taxon | Wherever found | |
| No common name | Phacelia dubia georgiana | Resolved Taxon | Wherever found | |
| No common name | Phacelia glaberrima | Resolved Taxon | Wherever found | |
| No common name | Phacelia incana | Resolved Taxon | Wherever found | |
| No common name | Phacelia inconspicua | Species of Concern | Wherever found | |
| No common name | Phacelia integrifolia texana | Resolved Taxon | Wherever found | |
| No common name | Phacelia peckii | Resolved Taxon | Wherever found | |
| No common name | Phacelia verna | Resolved Taxon | Wherever found | |
| No common name | Pheidole elecebra | Resolved Taxon | Wherever found | |
| No common name | Phialanthus myrtilloides | Species of Concern | Wherever found | |
| No common name | Philadelphus mearnsii | Resolved Taxon | Wherever found | |
| No common name | Philadelphus texensis texensis | Resolved Taxon | Wherever found | |
| No common name | Phlegmariurus stemmermanniae | Endangered | Wherever found | 10-31-2016 |
| No common name | Phlox buckleyi | Resolved Taxon | Wherever found | |
| No common name | Phlox peckii | Resolved Taxon | Wherever found | |
| No common name | Phreatodrobia coronae | Resolved Taxon | Wherever found | |
| No common name | Phyllanthus liebmannianus platylepis | Resolved Taxon | Wherever found | |
| No common name | Phyllanthus pentaphyllus floridanus | Species of Concern | Wherever found | |
| No common name | Phyllanthus saffordii | Endangered | Wherever found | 11-02-2015 |
| No common name | Phyllanthus sandwicensis degeneri | Resolved Taxon | Wherever found | |
| No common name | Phylloscopus examinandus | Species of Concern | | |
| No common name | Phyllostegia ambigua | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia bracteata | Endangered | Wherever found | 06-27-2013 |
| No common name | Phyllostegia brevidens | Endangered | Wherever found | 10-31-2016 |
| No common name | Phyllostegia brevidens ambigua | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia brevidens degeneri | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia brevidens heterodoxa | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia brevidens hirsutula | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia brevidens pubescens | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia floribunda | Endangered | Wherever found | 11-29-2013 |
| No common name | Phyllostegia glabra var. lanaiensis | Endangered | Wherever found | 09-20-1991 |
| No common name | Phyllostegia haliakalae | Endangered | Wherever found | 06-27-2013 |
| No common name | Phyllostegia helleri | Endangered | | 10-31-2016 |
| No common name | Phyllostegia hillebrandii | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia hirsuta | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia hispida | Endangered | Wherever found | 03-17-2009 |
| No common name | Phyllostegia imminuta | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia kaalaensis | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia knudsenii | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia mannii | Endangered | Wherever found | 10-08-1992 |
| No common name | Phyllostegia mollis | Endangered | Wherever found | 10-29-1991 |
| No common name | Phyllostegia mollis fagerlindii | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia parviflora | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia pilosa | Endangered | Wherever found | 06-27-2013 |
| No common name | Phyllostegia renovans | Endangered | Wherever found | 05-13-2010 |
| No common name | Phyllostegia rockii | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia stachyoides | Endangered | Wherever found | 10-31-2016 |
| No common name | Phyllostegia variabilis | Resolved Taxon | Wherever found | |
| No common name | Phyllostegia velutina | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia waimeae | Endangered | Wherever found | 02-25-1994 |
| No common name | Phyllostegia warshaueri | Endangered | Wherever found | 10-10-1996 |
| No common name | Phyllostegia wawrana | Endangered | Wherever found | 10-10-1996 |
| No common name | Physalis viscosa elliotii | Resolved Taxon | Wherever found | |
| No common name | Physaria acutifolia purpurea | Resolved Taxon | Wherever found | |
| No common name | Physaria didymocarpa lyrata | Species of Concern | Wherever found | |
| No common name | Physaria dornii | Resolved Taxon | Wherever found | |
| No common name | Physaria eburniflora | Species of Concern | Wherever found | |
| No common name | Physaria geyeri purpurea | Resolved Taxon | Wherever found | |
| No common name | Physogyra lichtensteini | Status Undefined | Wherever found | |
| No common name | Physostegia intermedia | Resolved Taxon | Wherever found | |
| No common name | Physostegia longisepala | Species of Concern | Wherever found | |
| No common name | Pieris phillyreifolia | Resolved Taxon | Wherever found | |
| No common name | Pilea leptophylla | Species of Concern | Wherever found | |
| No common name | Pilea multicaulis | Species of Concern | Wherever found | |
| No common name | Pilea richardii | Species of Concern | Wherever found | |
| No common name | Pilea yunquensis | Resolved Taxon | Wherever found | |
| No common name | Pinckneya bracteata | Resolved Taxon | Wherever found | |
| No common name | Pisonia floridana | Resolved Taxon | Wherever found | |
| No common name | Pisonia wagneriana | Species of Concern | Wherever found | |
| No common name | Pittosporum acuminatum leptopodum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum acuminatum magnifolium | Resolved Taxon | Wherever found | |
| No common name | Pittosporum acuminatum waimeanum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum argentifolium argentifolium | Resolved Taxon | Wherever found | |
| No common name | Pittosporum argentifolium sessile | Resolved Taxon | Wherever found | |
| No common name | Pittosporum cauliflorum cauliflorum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum cauliflorum cladanthoides | Resolved Taxon | Wherever found | |
| No common name | Pittosporum cauliflorum pedicellatum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum cladanthum gracilipes | Resolved Taxon | Wherever found | |
| No common name | Pittosporum confertiflorum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum confertiflorum longipes | Resolved Taxon | Wherever found | |
| No common name | Pittosporum confertiflorum microphyllum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum glabrum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum glabrum glomeratum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum glabrum intermedium | Resolved Taxon | Wherever found | |
| No common name | Pittosporum glabrum tinifolium | Resolved Taxon | Wherever found | |
| No common name | Pittosporum hosmeri | Resolved Taxon | Wherever found | |
| No common name | Pittosporum insigne micranthum | Resolved Taxon | Wherever found | |
| No common name | Pittosporum kauaiense repens | Resolved Taxon | Wherever found | |
| No common name | Pittosporum terminalioides lanaiense | Resolved Taxon | Wherever found | |
| No common name | Pittosporum terminalioides macropus | Resolved Taxon | Wherever found | |
| No common name | Pittosporum terminalioides mauiense | Resolved Taxon | Wherever found | |
| No common name | Pityopsis flexuosa | Species of Concern | Wherever found | |
| No common name | Plagiobothrys distantiflorus | Resolved Taxon | Wherever found | |
| No common name | Plagiochila columbiana | Species of Concern | Wherever found | |
| No common name | Plagiochila echinata | Species of Concern | Wherever found | |
| No common name | Plagiochila virginica euryphylla | Species of Concern | Wherever found | |
| No common name | Platanthera holochila | Endangered | Wherever found | 10-10-1996 |
| No common name | Platanthera integra | Resolved Taxon | Wherever found | |
| No common name | Platanthera zothecina | Species of Concern | Wherever found | |
| No common name | Plummera ambigens | Resolved Taxon | Wherever found | |
| No common name | Poa curtifolia | Resolved Taxon | Wherever found | |
| No common name | Poa laxiflora | Resolved Taxon | Wherever found | |
| No common name | Poa macrocalyx | Resolved Taxon | Wherever found | |
| No common name | Poa marcida | Resolved Taxon | Wherever found | |
| No common name | Poa palustris | Resolved Taxon | Wherever found | |
| No common name | Poa paucispicula | Resolved Taxon | Wherever found | |
| No common name | Poa siphonoglossa | Endangered | Wherever found | 05-13-1992 |
| No common name | Pocillopora danae | Status Undefined | Wherever found | |
| No common name | Pocillopora elegans | Status Undefined | Wherever found | |
| No common name | Podistera yukonensis | Species of Concern | Wherever found | |
| No common name | Polemonium nevadense | Resolved Taxon | Wherever found | |
| No common name | Polemonium pectinatum | Resolved Taxon | Wherever found | |
| No common name | Polygala alba | Status Undefined | Wherever found | |
| No common name | Polygala boykinii sparsifolia | Species of Concern | Wherever found | |
| No common name | Polygala paucifolia | Status Undefined | Wherever found | |
| No common name | Polygala piliophora | Resolved Taxon | Wherever found | |
| No common name | Polygala rimulicola rimulicola | Resolved Taxon | Wherever found | |
| No common name | Polygala subspinosa heterorhynca | Resolved Taxon | Wherever found | |
| No common name | Polygala verticillata | Status Undefined | Wherever found | |
| No common name | Polygonum cascadense | Resolved Taxon | Wherever found | |
| No common name | Polygonum utahense | Resolved Taxon | Wherever found | |
| No common name | Polymnia laevigata | Resolved Taxon | Wherever found | |
| No common name | Polyscias bisattenuata | Endangered | Wherever found | 05-13-2010 |
| No common name | Polyscias flynnii | Endangered | Wherever found | 05-13-2010 |
| No common name | Polyscias lydgatei | Endangered | Wherever found | 10-18-2012 |
| No common name | Polyscias racemosa | Endangered | Wherever found | 02-25-1994 |
| No common name | Polystichum calderonense | Endangered | Wherever found | 06-09-1993 |
| No common name | Porella appalachiana | Species of Concern | Wherever found | |
| No common name | Porites horizontalata | Status Undefined | Wherever found | |
| No common name | Porites napopora | Threatened | Wherever found | 11-13-2014 |
| No common name | Porites nigrescens | Status Undefined | Wherever found | |
| No common name | Porophyllum greggii | Resolved Taxon | Wherever found | |
| No common name | Porophyllum pygmaeum | Species of Concern | Wherever found | |
| No common name | Portulaca caulerpoides | Resolved Taxon | Wherever found | |
| No common name | Portulaca molokiniensis | Species of Concern | Wherever found | |
| No common name | Portulaca smallii | Resolved Taxon | Wherever found | |
| No common name | Potamogeton lateralis | Resolved Taxon | Wherever found | |
| No common name | Potentilla angelliae | Resolved Taxon | Wherever found | |
| No common name | Potentilla cottamii | Resolved Taxon | Wherever found | |
| No common name | Potentilla sierrae-blancae | Resolved Taxon | Wherever found | |
| No common name | Priva portoricensis | Resolved Taxon | Wherever found | |
| No common name | Proatriplex pleiantha | Resolved Taxon | Wherever found | |
| No common name | Prunus alleghaniensis davisii | Species of Concern | Wherever found | |
| No common name | Prunus havardii | Resolved Taxon | Wherever found | |
| No common name | Prunus minutiflora | Resolved Taxon | Wherever found | |
| No common name | Prunus murrayana | Resolved Taxon | Wherever found | |
| No common name | Prunus texana | Resolved Taxon | Wherever found | |
| No common name | Pseudocopaeodes eunus alinea | Resolved Taxon | Wherever found | |
| No common name | Pseudocopaeodes eunus flavus | Resolved Taxon | Wherever found | |
| No common name | Pseudocopaeodes eunus ssp. | Resolved Taxon | Wherever found | |
| No common name | Pseudognaphalium macounii | Resolved Taxon | Wherever found | |
| No common name | Pseudosinella vita | Resolved Taxon | Wherever found | |
| No common name | Psorothamnus kingii | Resolved Taxon | Wherever found | |
| No common name | Psorothamnus polydenius var. jonesii | Species of Concern | Wherever found | |
| No common name | Psychilis krugii | Resolved Taxon | Wherever found | |
| No common name | Psychotria insularum paradisii | Resolved Taxon | Wherever found | |
| No common name | Pteris lidgatei | Endangered | Wherever found | 09-26-1994 |
| No common name | ptomaphagus cocytus | Resolved Taxon | Wherever found | |
| No common name | Pycnanthemum curvipes | Resolved Taxon | Wherever found | |
| No common name | Pycnanthemum floridanum | Resolved Taxon | Wherever found | |
| No common name | Pyrrocoma insecticruris | Resolved Taxon | Wherever found | |
| No common name | Pyrrocoma liatriformis | Species of Concern | Wherever found | |
| No common name | Quadrula cylindrica | Status Undefined | Wherever found | |
| No common name | Rallus obsoletus | Species of Concern | | |
| No common name | Randia portoricensis | Species of Concern | Wherever found | |
| No common name | Ranunculus austro-oreganus | Species of Concern | Wherever found | |
| No common name | Ranunculus occidentalis nelsonii | Resolved Taxon | Wherever found | |
| No common name | Ranunculus triternatus | Species of Concern | Wherever found | |
| No common name | Rauvolfia helleri | Resolved Taxon | Wherever found | |
| No common name | Rauvolfia mauiensis | Resolved Taxon | Wherever found | |
| No common name | Rauvolfia molokaiensis parvifolia | Resolved Taxon | Wherever found | |
| No common name | Rauvolfia sandwicensis subacuminata | Resolved Taxon | Wherever found | |
| No common name | Remya kauaiensis | Endangered | Wherever found | 01-14-1991 |
| No common name | Remya montgomeryi | Endangered | Wherever found | 01-14-1991 |
| No common name | rhadine austinica | Resolved Taxon | Wherever found | |
| No common name | rhadine insolita | Resolved Taxon | Wherever found | |
| No common name | rhadine noctivaga | Resolved Taxon | Wherever found | |
| No common name | rhadine russelli | Resolved Taxon | Wherever found | |
| No common name | Rhinanthus arcticus | Resolved Taxon | Wherever found | |
| No common name | Rhipsalis baccifera | Resolved Taxon | Wherever found | |
| No common name | Rhododon ciliatus | Resolved Taxon | Wherever found | |
| No common name | Rhynchosia cinerea | Resolved Taxon | Wherever found | |
| No common name | Riccia californica | Not Listed | | |
| No common name | Riccia ozarkiana | Resolved Taxon | Wherever found | |
| No common name | Rollandia angustifolia ochreata | Resolved Taxon | Wherever found | |
| No common name | Rollandia degenerana | Resolved Taxon | Wherever found | |
| No common name | Romanzoffia thompsonii | Resolved Taxon | Wherever found | |
| No common name | Rorippa aquatica | Resolved Taxon | Wherever found | |
| No common name | Rorippa calycina | Species of Concern | Wherever found | |
| No common name | Rosa stellata stellata | Resolved Taxon | Wherever found | |
| No common name | Rubus bartonianus | Species of Concern | Wherever found | |
| No common name | Rubus macraei | Species of Concern | Wherever found | |
| No common name | Rubus missouricus | Resolved Taxon | Wherever found | |
| No common name | Rubus nigerrimus | Species of Concern | Wherever found | |
| No common name | Ruellia drummondiana | Resolved Taxon | Wherever found | |
| No common name | Rumex spiralis | Resolved Taxon | Wherever found | |
| No common name | Sageretia minutiflora | Resolved Taxon | Wherever found | |
| No common name | Salvia dorrii clokeyi | Species of Concern | Wherever found | |
| No common name | Sanicula kauaiensis | Species of Concern | Wherever found | |
| No common name | Sanicula mariversa | Endangered | Wherever found | 10-29-1991 |
| No common name | Sanicula purpurea | Endangered | Wherever found | 10-10-1996 |
| No common name | Sanicula sandwicensis | Endangered | Wherever found | 10-31-2016 |
| No common name | Santalum ellipticum littorale | Resolved Taxon | Wherever found | |
| No common name | Santalum involutum | Endangered | Wherever found | 10-31-2016 |
| No common name | Santalum salicifolium | Resolved Taxon | Wherever found | |
| No common name | Saussurea weberi | Resolved Taxon | Wherever found | |
| No common name | Saxifraga bryophora tobiasiae | Species of Concern | Wherever found | |
| No common name | Scaevola gaudichaudiana | Resolved Taxon | Wherever found | |
| No common name | Schiedea attenuata | Endangered | Wherever found | 05-13-2010 |
| No common name | Schiedea diffusa ssp. macraei | Endangered | Wherever found | 11-29-2013 |
| No common name | Schiedea diffusa subsp. diffusa | Endangered | Wherever found | 10-31-2016 |
| No common name | Schiedea haleakalensis | Endangered | Wherever found | 05-15-1992 |
| No common name | Schiedea helleri | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea hookeri | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea implexa | Resolved Taxon | Wherever found | |
| No common name | Schiedea jacobii | Endangered | Wherever found | 06-27-2013 |
| No common name | Schiedea kaalae | Endangered | Wherever found | 10-29-1991 |
| No common name | Schiedea kauaiensis | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea laui | Endangered | Wherever found | 06-27-2013 |
| No common name | Schiedea lydgatei | Endangered | Wherever found | 10-08-1992 |
| No common name | Schiedea mannii | Resolved Taxon | Wherever found | |
| No common name | Schiedea membranacea | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea menziesii | Species of Concern | Wherever found | |
| No common name | Schiedea nuttallii | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea obovata | Endangered | Wherever found | 10-29-1991 |
| No common name | Schiedea salicaria | Endangered | Wherever found | 06-27-2013 |
| No common name | Schiedea sarmentosa | Endangered | Wherever found | 10-10-1996 |
| No common name | Schiedea spergulina var. leiopoda | Endangered | Wherever found | 02-25-1994 |
| No common name | Schiedea spergulina var. spergulina | Threatened | Wherever found | 02-25-1994 |
| No common name | Schiedea trinervis | Endangered | Wherever found | 10-29-1991 |
| No common name | Schiedea verticillata | Endangered | Wherever found | 08-21-1996 |
| No common name | Schiedea viscosa | Endangered | Wherever found | 10-10-1996 |
| No common name | Schisandra glabra | Resolved Taxon | Wherever found | |
| No common name | Schizachyrium niveum | Species of Concern | Wherever found | |
| No common name | Schizachyrium rhizomatum | Resolved Taxon | Wherever found | |
| No common name | Schoepfia arenaria | Threatened | Wherever found | 04-19-1991 |
| No common name | Scleria hirtella | Resolved Taxon | Wherever found | |
| No common name | Sclerocactus contortus | Resolved Taxon | Wherever found | |
| No common name | Sclerocactus spinosior | Resolved Taxon | Wherever found | |
| No common name | Sclerocactus warnockii | Resolved Taxon | Wherever found | |
| No common name | Sclerocactus whipplei heilii | Resolved Taxon | Wherever found | |
| No common name | Sclerocactus whipplei reevesii | Resolved Taxon | Wherever found | |
| No common name | Selaginella utahensis | Resolved Taxon | Wherever found | |
| No common name | Senecio hydrophilus | Resolved Taxon | Wherever found | |
| No common name | Senecio lynceus leucoreus | Resolved Taxon | Wherever found | |
| No common name | Senecio neowebsteri | Resolved Taxon | Wherever found | |
| No common name | Senecio spribillei | Resolved Taxon | Wherever found | |
| No common name | Senecio warnockii | Resolved Taxon | Wherever found | |
| No common name | Seriatopora aculeata | Threatened | Wherever found | 11-13-2014 |
| No common name | Setophaga adelaidae | Species of Concern | | |
| No common name | Seymeria bipinnatisecta | Resolved Taxon | Wherever found | |
| No common name | Shoshonea pulvinata | Species of Concern | Wherever found | |
| No common name | Sibara grisea | Resolved Taxon | Wherever found | |
| No common name | Sibara rosulata | Resolved Taxon | Wherever found | |
| No common name | Sibirionetta formosa | Species of Concern | | |
| No common name | Sicyos hillebrandii | Resolved Taxon | Wherever found | |
| No common name | Sicyos lanceoloideus | Endangered | Wherever found | 10-31-2016 |
| No common name | Sicyos maximowiczii | Resolved Taxon | Wherever found | |
| No common name | Sicyos pachycarpus | Resolved Taxon | Wherever found | |
| No common name | Sicyos semitonsus | Resolved Taxon | Wherever found | |
| No common name | Sida fallax | Resolved Taxon | Wherever found | |
| No common name | Sida inflexa | Species of Concern | Wherever found | |
| No common name | Sidalcea candida | Resolved Taxon | Wherever found | |
| No common name | Sidalcea cusickii | Resolved Taxon | Wherever found | |
| No common name | Sidalcea setosa | Resolved Taxon | Wherever found | |
| No common name | Sida rubromarginata | Resolved Taxon | Wherever found | |
| No common name | Siderastrea glynni | Endangered | | 11-06-2015 |
| No common name | Silene alexandri | Endangered | Wherever found | 10-08-1992 |
| No common name | Silene aperta | Resolved Taxon | Wherever found | |
| No common name | Silene clokeyi | Species of Concern | Wherever found | |
| No common name | Silene cryptopetala | Resolved Taxon | Wherever found | |
| No common name | Silene degeneri | Resolved Taxon | Wherever found | |
| No common name | Silene hawaiiensis | Threatened | Wherever found | 03-04-1994 |
| No common name | Silene lanceolata | Endangered | Wherever found | 10-08-1992 |
| No common name | Silene perlmanii | Endangered | Wherever found | 10-29-1991 |
| No common name | Silene scaposa lobata | Resolved Taxon | Wherever found | |
| No common name | Silene scaposa scaposa | Resolved Taxon | Wherever found | |
| No common name | Silene seelyi | Species of Concern | Wherever found | |
| No common name | Silene wrightii | Resolved Taxon | Wherever found | |
| No common name | Silphium confertifolium | Species of Concern | Wherever found | |
| No common name | Smelowskia borealis villosa | Resolved Taxon | Wherever found | |
| No common name | Smelowskia holmgrenii | Resolved Taxon | Wherever found | |
| No common name | Smelowskia pyriformis | Species of Concern | Wherever found | |
| No common name | Smilax melastomifolia melastomifolia | Resolved Taxon | Wherever found | |
| No common name | Smilax pseudochina | Species of Concern | Wherever found | |
| No common name | Solanum carolinense floridanum | Resolved Taxon | Wherever found | |
| No common name | Solanum mucronatum | Species of Concern | Wherever found | |
| No common name | Solanum woodburyi | Resolved Taxon | Wherever found | |
| No common name | Solidago arguta harrissii | Resolved Taxon | Wherever found | |
| No common name | Solidago mollis angustata | Resolved Taxon | Wherever found | |
| No common name | Solidago ouachitensis | Resolved Taxon | Wherever found | |
| No common name | Solidago petiolaris | Resolved Taxon | Wherever found | |
| No common name | Solidago sphathulata gillmanii | Species of Concern | Wherever found | |
| No common name | sonorarctia fervida | Resolved Taxon | Wherever found | |
| No common name | Sophora arizonica | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla circularis | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla elliptica | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla glabrata | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla grisea | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla kanaioensis | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla kauensis | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla makuaensis | Resolved Taxon | Wherever found | |
| No common name | Sophora chrysophylla unifoliata | Resolved Taxon | Wherever found | |
| No common name | Sophora leachiana | Species of Concern | Wherever found | |
| No common name | Spatula querquedula | Species of Concern | | |
| No common name | Spermolepis hawaiiensis | Endangered | Wherever found | 11-10-1994 |
| No common name | Sphaeralcea janeae | Resolved Taxon | Wherever found | |
| No common name | Sphaeralcea procera | Resolved Taxon | Wherever found | |
| No common name | Sphaeralcea psoraloides | Species of Concern | Wherever found | |
| No common name | sphingicampa raspa | Status Undefined | Wherever found | |
| No common name | Sphinx eremitoides | Status Undefined | Wherever found | |
| No common name | Spigelia texana | Resolved Taxon | Wherever found | |
| No common name | Spodiopsar cineraceus | Species of Concern | | |
| No common name | Sporophila morelleti | Species of Concern | | |
| No common name | Stanleya pinnata gibberosa | Resolved Taxon | Wherever found | |
| No common name | Stenandrium fascicularis | Resolved Taxon | Wherever found | |
| No common name | Stenogyne affinis degeneri | Resolved Taxon | Wherever found | |
| No common name | Stenogyne angustifolia var. angustifolia | Endangered | Wherever found | 11-29-1979 |
| No common name | Stenogyne bifida | Endangered | Wherever found | 10-08-1992 |
| No common name | Stenogyne campanulata | Endangered | Wherever found | 05-13-1992 |
| No common name | Stenogyne cinerea | Resolved Taxon | Wherever found | |
| No common name | Stenogyne cranwelliae | Endangered | Wherever found | 11-29-2013 |
| No common name | Stenogyne haliakalae | Species of Concern | Wherever found | |
| No common name | Stenogyne kaalae ssp. sherffii | Endangered | Wherever found | 10-31-2016 |
| No common name | Stenogyne kanehoana | Endangered | Wherever found | 05-13-1992 |
| No common name | Stenogyne kauaulaensis | Endangered | Wherever found | 06-27-2013 |
| No common name | Stenogyne kealiae | Endangered | Wherever found | 05-13-2010 |
| No common name | Stenogyne macrantha | Resolved Taxon | Wherever found | |
| No common name | Stenogyne microphylla | Resolved Taxon | Wherever found | |
| No common name | Stenogyne oxygona | Species of Concern | Wherever found | |
| No common name | Stenogyne purpurea forbesii | Resolved Taxon | Wherever found | |
| No common name | Stenogyne rotundifolia | Resolved Taxon | Wherever found | |
| No common name | Stenogyne rotundifolia oblonga | Resolved Taxon | Wherever found | |
| No common name | Stenogyne rugosa | Resolved Taxon | Wherever found | |
| No common name | Stenogyne rugosa mollis | Resolved Taxon | Wherever found | |
| No common name | Stenogyne salicifolia | Resolved Taxon | Wherever found | |
| No common name | Stenogyne scrophularioides | Resolved Taxon | Wherever found | |
| No common name | Stenogyne sessilis hexantha | Resolved Taxon | Wherever found | |
| No common name | Stenogyne sessilis laniensis | Resolved Taxon | Wherever found | |
| No common name | Stenogyne sessilis wilkesii | Resolved Taxon | Wherever found | |
| No common name | Stenogyne viridis | Resolved Taxon | Wherever found | |
| No common name | Stillingia sylvatica tenuis | Species of Concern | Wherever found | |
| No common name | Streptanthus carinatus | Resolved Taxon | Wherever found | |
| No common name | Stylocline citroleum | Species of Concern | Wherever found | |
| No common name | Stylocline masonii | Species of Concern | Wherever found | |
| No common name | Styphelia tameiameiae hexamera | Resolved Taxon | Wherever found | |
| No common name | Suaeda rolandii | Species of Concern | Wherever found | |
| No common name | Succinea pseudavara | Resolved Taxon | Wherever found | |
| No common name | Sullivantia hapemanii | Species of Concern | Wherever found | |
| No common name | Sullivantia oregana | Species of Concern | Wherever found | |
| No common name | Sullivantia purpusii | Resolved Taxon | Wherever found | |
| No common name | Suwallia salish | Resolved Taxon | Wherever found | |
| No common name | Synthyris canbyi | Resolved Taxon | Wherever found | |
| No common name | Synthyris missurica hirsuta | Resolved Taxon | Wherever found | |
| No common name | Synthyris missurica stellata | Resolved Taxon | Wherever found | |
| No common name | Synthyris pinnatifida canescens | Resolved Taxon | Wherever found | |
| No common name | Synthyris pinnatifida lanuginosa | Resolved Taxon | Wherever found | |
| No common name | Synthyris platycarpa | Resolved Taxon | Wherever found | |
| No common name | Synthyris schizantha | Resolved Taxon | Wherever found | |
| No common name | Syntrichia princeps | Not Listed | | |
| No common name | Tabernaemontana rotensis | Threatened | Wherever found | 11-02-2015 |
| No common name | Tagetes lemmonii | Resolved Taxon | Wherever found | |
| No common name | Taraxacum carneocoloratum | Species of Concern | Wherever found | |
| No common name | tartarocreagris intermedia | Resolved Taxon | Wherever found | |
| No common name | Tauschia stricklandii | Resolved Taxon | Wherever found | |
| No common name | Tauschia tenuissima | Resolved Taxon | Wherever found | |
| No common name | Tectaria amesiana | Species of Concern | Wherever found | |
| No common name | Tectaria estremerana | Endangered | Wherever found | 06-09-1993 |
| No common name | Teloschistes villosus | Species of Concern | Wherever found | |
| No common name | Tephrosia angustissima | Species of Concern | Wherever found | |
| No common name | Ternstroemia subsessilis | Endangered | Wherever found | 04-22-1992 |
| No common name | Tetramolopium arenarium | Endangered | Wherever found | 03-04-1994 |
| No common name | Tetramolopium consanguineum consanguineum | Resolved Taxon | Wherever found | |
| No common name | Tetramolopium consanguineum leptophyllum | Species of Concern | Wherever found | |
| No common name | Tetramolopium conyzoides | Resolved Taxon | Wherever found | |
| No common name | Tetramolopium filiforme | Endangered | Wherever found | 10-29-1991 |
| No common name | Tetramolopium humile sublaeve | Species of Concern | Wherever found | |
| No common name | Tetramolopium kavaiensis koloana | Resolved Taxon | Wherever found | |
| No common name | Tetramolopium lepidotum arbusculum | Resolved Taxon | Wherever found | |
| No common name | Tetramolopium lepidotum ssp. lepidotum | Endangered | Wherever found | 10-29-1991 |
| No common name | Tetramolopium remyi | Endangered | Wherever found | 09-20-1991 |
| No common name | Tetramolopium rockii | Threatened | Wherever found | 10-08-1992 |
| No common name | Tetramolopium tenerrimum | Resolved Taxon | Wherever found | |
| No common name | Tetramolopius kavaiensis koloana | Resolved Taxon | Wherever found | |
| No common name | Tetraneuris torreyana | Species of Concern | Wherever found | |
| No common name | Tetraneuris turneri | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra hawaiiensis hawaiiensis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra kahanana | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra kohalae | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra lanaiensis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra lihuensis gracilipes | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra bisobtusa | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra bryanii | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra degeneri | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra hillebrandii | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra hiloensis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra leptomera | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra makalehana | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra rhynchocarpoides | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra meiandra simulans | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra munroi | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra oahuensis eradiata | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra oahuensis fauriei | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra oahuensis hailiensis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra oahuensis longipes | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra oahuensis pseudorhachis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra pupukeensis nitida | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra pupukeensis pupukeensis | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra pupukeensis venosa | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra turbans | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra waialealae urceolata | Resolved Taxon | Wherever found | |
| No common name | Tetraplasandra waimeae angustior | Resolved Taxon | Wherever found | |
| No common name | texella brevidenta | Resolved Taxon | Wherever found | |
| No common name | texella brevistyla | Resolved Taxon | Wherever found | |
| No common name | texella diplospina | Resolved Taxon | Wherever found | |
| No common name | texella fendi | Resolved Taxon | Wherever found | |
| No common name | texella grubbsi | Resolved Taxon | Wherever found | |
| No common name | texella hardeni | Resolved Taxon | Wherever found | |
| No common name | texella renkesae | Resolved Taxon | Wherever found | |
| No common name | texella welbourni | Resolved Taxon | Wherever found | |
| No common name | texiweckelia relicta | Resolved Taxon | Wherever found | |
| No common name | Thalictrum arkansanum | Species of Concern | Wherever found | |
| No common name | Thalictrum heliophilum | Resolved Taxon | Wherever found | |
| No common name | Thalictrum mirabile | Species of Concern | Wherever found | |
| No common name | thalkethops grallatrix | Resolved Taxon | Wherever found | |
| No common name | Thelesperma caespitosum | Resolved Taxon | Wherever found | |
| No common name | Thelesperma pubescens | Resolved Taxon | Wherever found | |
| No common name | Thelesperma subnudum alpinum | Species of Concern | Wherever found | |
| No common name | Thelocactus bicolor flavidispinus | Species of Concern | Wherever found | |
| No common name | Thelypodiopsis purpusii | Resolved Taxon | Wherever found | |
| No common name | Thelypodium eucosmum | Species of Concern | Wherever found | |
| No common name | Thelypodium laxiflorum | Resolved Taxon | Wherever found | |
| No common name | Thelypodium sagittatum ovalifolium | Resolved Taxon | Wherever found | |
| No common name | Thelypteris hastata heterodoxa | Species of Concern | Wherever found | |
| No common name | Thelypteris inabonensis | Endangered | Wherever found | 07-02-1993 |
| No common name | Thelypteris verecunda | Endangered | Wherever found | 07-02-1993 |
| No common name | Thelypteris yaucoensis | Endangered | Wherever found | 07-02-1993 |
| No common name | Thismia americana | Species of Concern | Wherever found | |
| No common name | Thlaspi arcticum | Resolved Taxon | Wherever found | |
| No common name | Thlaspi montanum siskiyouense | Resolved Taxon | Wherever found | |
| No common name | Thryophilus sinaloa | Species of Concern | | |
| No common name | thymoites minero | Resolved Taxon | Wherever found | |
| No common name | Tinospora homosepala | Endangered | Wherever found | 11-02-2015 |
| No common name | Tithonia thurberi | Resolved Taxon | Wherever found | |
| No common name | Todiramphus sacer | Species of Concern | | |
| No common name | Tofieldia glutinosa absona | Species of Concern | Wherever found | |
| No common name | Toiyabea alpina | Species of Concern | Wherever found | |
| No common name | Tomocerus grahami | Resolved Taxon | Wherever found | |
| No common name | Tonestus graniticus | Species of Concern | Wherever found | |
| No common name | Townsendia alpigena minima | Resolved Taxon | Wherever found | |
| No common name | Townsendia jonesii tumulosa | Species of Concern | Wherever found | |
| No common name | Tradescantia edwardsiana | Resolved Taxon | Wherever found | |
| No common name | Tradescantia ozarkana | Species of Concern | Wherever found | |
| No common name | Tragia nigricans | Resolved Taxon | Wherever found | |
| No common name | Tragia saxicola | Species of Concern | Wherever found | |
| No common name | Trematolobelia grandifolia | Species of Concern | Wherever found | |
| No common name | Trematolobelia singularis | Endangered | Wherever found | 10-10-1996 |
| No common name | Trichomanes draytonianum | Resolved Taxon | Wherever found | |
| No common name | Trifolium andinum podocephalum | Species of Concern | Wherever found | |
| No common name | Trillium pusillum monticulum | Species of Concern | Wherever found | |
| No common name | Triniteurybia aberrans | Resolved Taxon | Wherever found | |
| No common name | Trisetum orthochaetum | Resolved Taxon | Wherever found | |
| No common name | Triteleia lemmonae | Resolved Taxon | Wherever found | |
| No common name | Triteleiopsis palmeri | Resolved Taxon | Wherever found | |
| No common name | Troglodytes pacificus | Species of Concern | | |
| No common name | Trollius laxus laxus | Resolved Taxon | Wherever found | |
| No common name | Tubastraea floreana | Endangered | | 11-06-2015 |
| No common name | tuberochernes ubicki | Resolved Taxon | Wherever found | |
| No common name | Tuberolabium guamense | Threatened | Wherever found | 11-02-2015 |
| No common name | Urera glabra | Resolved Taxon | Wherever found | |
| No common name | ursia furtiva | Under Review | Wherever found | |
| No common name | Urtica chamaedryoides | Resolved Taxon | Wherever found | |
| No common name | Usnea longissima | Resolved Taxon | Wherever found | |
| No common name | Vaccinium vacillans missouriense | Resolved Taxon | Wherever found | |
| No common name | Valeriana columbiana | Resolved Taxon | Wherever found | |
| No common name | Varronia rupicola | Threatened | Wherever found | 10-09-2014 |
| No common name | Verbesina heterophylla | Species of Concern | Wherever found | |
| No common name | Vernonia borinquensis | Species of Concern | Wherever found | |
| No common name | Vernonia proctorii | Endangered | Wherever found | 04-27-1993 |
| No common name | Vernonia pulchella | Resolved Taxon | Wherever found | |
| No common name | Veronica peregrina | Resolved Taxon | Wherever found | |
| No common name | Verrucaria kootenaica | Resolved Taxon | Wherever found | |
| No common name | Vigna o-wahuensis | Endangered | Wherever found | 11-10-1994 |
| No common name | Viola adunca cascadensis | Resolved Taxon | Wherever found | |
| No common name | Viola egglestonii | Resolved Taxon | Wherever found | |
| No common name | Viola helenae | Endangered | Wherever found | 09-20-1991 |
| No common name | Viola lanaiensis | Endangered | Wherever found | 09-20-1991 |
| No common name | Viola lithion | Resolved Taxon | Wherever found | |
| No common name | Viola oahuensis | Endangered | Wherever found | 10-10-1996 |
| No common name | Viola robusta | Resolved Taxon | Wherever found | |
| No common name | Waldsteinia idahoensis | Resolved Taxon | Wherever found | |
| No common name | Waltheria pyrolaefolia | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia basicorda | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia hanalei | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia isae | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia leptantha | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia monticola occidentalis | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia sandwicensis | Resolved Taxon | Wherever found | |
| No common name | Wikstroemia skottsbergiana | Endangered | | 10-31-2016 |
| No common name | Wikstroemia villosa | Endangered | Wherever found | 06-27-2013 |
| No common name | Wilkstroemia bicornuta | Species of Concern | Wherever found | |
| No common name | Willkommia texana | Resolved Taxon | Wherever found | |
| No common name | Woodsia abbeae | Resolved Taxon | Wherever found | |
| No common name | xanthoparmelia dissensa | Resolved Taxon | Wherever found | |
| No common name | Xanthoparmelia idahoensis | Resolved Taxon | Wherever found | |
| No common name | Xanthoparmelia neowyomingica | Resolved Taxon | Wherever found | |
| No common name | xanthoparmelia planilobata | Resolved Taxon | Wherever found | |
| No common name | Xylorhiza confertifolia | Resolved Taxon | Wherever found | |
| No common name | Xylorhiza cronquistii | Resolved Taxon | Wherever found | |
| No common name | Xylosma crenatum | Endangered | Wherever found | 05-13-1992 |
| No common name | Xyris isoetifolia | Species of Concern | Wherever found | |
| No common name | Xyris scabrifolia | Species of Concern | Wherever found | |
| No common name | Yucca angustissima toftiae | Resolved Taxon | Wherever found | |
| No common name | yucca cernua | Resolved Taxon | Wherever found | |
| No common name | Zanthoxylum glandulosum | Resolved Taxon | Wherever found | |
| No common name | Zanthoxylum kauaense kohuana | Resolved Taxon | Wherever found | |
| No common name | Zanthoxylum maviense | Resolved Taxon | Wherever found | |
| No common name | Zephyranthes simpsonii | Resolved Taxon | Wherever found | |
| No common name | Zephyranthes treatiae | Resolved Taxon | Wherever found | |
| No common name | Zizia trifoliata | Species of Concern | Wherever found | |
| No Common name | Caecidotea adenta | Resolved Taxon | Wherever found | |
| No Common Name | Coccyzus americanus ssp. occidentalis | Species of Concern | Wherever found | |
| No Common Name | Holsingerius samacos | Resolved Taxon | Wherever found | |
| No Common Name | Holsingerius smaragdinus | Resolved Taxon | Wherever found | |
| No Common Name | Leucohya texana | Resolved Taxon | Wherever found | |
| No Common Name | Pseudogarypus hypogeus | Resolved Taxon | Wherever found | |
| No Common Name | Speodesmus aquiliensis | Resolved Taxon | Wherever found | |
| [no common name] Beetle | Rhadine exilis | Endangered | Wherever found | 12-26-2000 |
| [no common name] Beetle | Rhadine infernalis | Endangered | Wherever found | 12-26-2000 |
| Nodding needlegrass | Nassella cernua | Resolved Taxon | Wherever found | |
| Nodding rock-daisy | Perityle cernua | Species of Concern | Wherever found | |
| Noel's Amphipod | Gammarus desperatus | Endangered | Wherever found | 08-09-2005 |
| Nohoanu | Geranium arboreum | Endangered | Wherever found | 05-13-1992 |
| Nohoanu | Geranium hanaense | Endangered | Wherever found | 06-27-2013 |
| Nohoanu | Geranium hillebrandii | Endangered | Wherever found | 06-27-2013 |
| Nohoanu | Geranium kauaiense | Endangered | Wherever found | 05-13-2010 |
| Nohoanu | Geranium multiflorum | Endangered | Wherever found | 05-15-1992 |
| Noisy scrub-bird | Atrichornis clamosus | Endangered | Wherever found | 06-02-1970 |
| None | Esenbeckia berlandieri | Resolved Taxon | Wherever found | |
| Noni kuahiwi | Morinda trimera | Resolved Taxon | Wherever found | |
| noonday snail | Mesodon clarki nantahala | Threatened | Wherever found | 08-02-1978 |
| Nordmann's greenshank | Tringa guttifer | Endangered | Wherever found | 06-14-1976 |
| Norfolk Island parakeet | Cyanoramphus cookii (=novaezelandiae c.) | Endangered | Wherever found | 09-28-1990 |
| Norfolk Island white-eye | Zosterops albogularis | Endangered | Wherever found | 06-14-1976 |
| North American wolverine | Gulo gulo luscus | Resolved Taxon | Nonessential Experimental Population of the North American Wolverine in Colorado, Wyoming, and New Mexico | |
| North American wolverine | Gulo gulo luscus | Threatened | Wherever found | 01-02-2024 |
| North Andean huemul | Hippocamelus antisensis | Endangered | Wherever found | 06-14-1976 |
| North Atlantic Right Whale | Eubalaena glacialis | Endangered | Wherever found | 06-02-1970 |
| North China sika deer | Cervus nippon mandarinus | Endangered | Wherever found | 07-27-1979 |
| Northcoast birds-beak | Cordylanthus maritimus palustris | Species of Concern | Wherever found | |
| Northcoast phacelia | Phacelia insularis continentis | Species of Concern | Wherever found | |
| Northcoast semaphore grass | Pleuropogon hooverianus | Species of Concern | Wherever found | |
| Northeastern beach tiger beetle | Habroscelimorpha dorsalis dorsalis | Threatened | Wherever found | 08-07-1990 |
| Northeastern bulrush | Scirpus ancistrochaetus | Endangered | | 05-07-1991 |
| Northeastern pygmy shrew | Microsorex hoyi thompsoni | Resolved Taxon | Wherever found | |
| Northern Alaska Dunlin | Calidris alpina arcticola | Species of Concern | Wherever found | |
| Northern Aplomado Falcon | Falco femoralis septentrionalis | Endangered | Wherever found, except where listed as an experimental population | 02-25-1986 |
| Northern Aplomado Falcon | Falco femoralis septentrionalis | Experimental Population, Non-Essential | U.S.A (AZ, NM) | 07-26-2006 |
| Northern bald ibis | Geronticus eremita | Endangered | Wherever found | 09-28-1990 |
| Northern Beardless-Tyrannulet | Camptostoma imberbe | Species of Concern | Wherever found | |
| northern bog lemming | Synaptomys borealis | Under Review | | |
| Northern bog lemming | Synaptomys borealis sphagnicola | Not Listed | Wherever found | |
| Northern Brook Lamprey | Ichthyomyzon fossor | Not Listed | | |
| Northern California black walnut | Juglans californica hindsii | Species of Concern | Wherever found | |
| Northern cavefish | Amblyopsis spelaea | Resolved Taxon | Wherever found | |
| Northern Cricket Frog | Acris crepitans | Not Listed | | |
| Northern diamondback terrapin | Malaclemys terrapin terrapin | Species of Concern | Wherever found | |
| Northern Flicker | Colaptes auratus | Status Undefined | Wherever found | |
| Northern Fulmar | Fulmarus glacialis | Species of Concern | Wherever found | |
| Northern Gannet | Morus bassanus | Species of Concern | Wherever found | |
| Northern goshawk | Accipiter gentilis | Resolved Taxon | Wherever found | |
| Northern gray hawk | Buteo nitidus maximus | Species of Concern | Wherever found | |
| Northern Harrier | Circus hudsonius | Species of Concern | Wherever found | |
| Northern Hog Sucker | Hypentelium nigricans | Not Listed | | |
| Northern Idaho Ground Squirrel | Urocitellus brunneus | Threatened | Wherever found | 04-05-2000 |
| Northern Lance | Elliptio fisheriana | Not Listed | | |
| Northern leatherside Chub | Lepidomeda copei | Resolved Taxon | Wherever found | |
| northern leopard frog | Rana pipiens | Resolved Taxon | western United States | |
| Northern Leopard Frog | Lithobates pipiens | Not Listed | | |
| Northern Long-Eared Bat | Myotis septentrionalis | Endangered | Wherever found | 05-04-2015 |
| Northern Madtom | Noturus stigmosus | Not Listed | | |
| Northern Mexican gartersnake | Thamnophis eques megalops | Threatened | Wherever found | 07-08-2014 |
| Northern (=New England) reedgrass | Calamagrostis inexpansa novae-angliae | Resolved Taxon | Wherever found | |
| Northern Oconee Bells | Shortia galacifolia var. brevistyla | Species of Concern | Wherever found | |
| Northern Pike | Esox lucius | Not Listed | | |
| Northern Pikeminnow | Ptychocheilus oregonensis | Not Listed | | |
| Northern pine snake | Pituophis melanoleucus melanoleucus | Species of Concern | Wherever found | |
| Northern pygmy-owl | Glaucidium gnoma | Not Listed | | |
| Northern Redbelly Dace | Chrosomus eos | Not Listed | | |
| Northern red diamond rattlesnake | Crotalus ruber ruber | Species of Concern | Wherever found | |
| Northern red-legged frog | Rana aurora aurora | Species of Concern | Wherever found | |
| Northern riffleshell | Epioblasma rangiana | Endangered | Wherever found | 01-22-1993 |
| Northern Roach | Hesperoleucus mitrulus | Not Listed | | |
| northern rockhopper penguin | Eudyptes moseleyi | Resolved Taxon | Wherever found | |
| Northern Rough winged Swallow | Stelgidopteryx serripennis | Status Undefined | Wherever found | |
| Northern sagebrush lizard | Sceloporus graciosus graciosus | Species of Concern | Wherever found | |
| Northern Saw-whet Owl | Aegolius acadicus | Species of Concern | Wherever found | |
| Northern Sea Otter | Enhydra lutris kenyoni | Not Listed | Wherever found | |
| Northern Sea Otter | Enhydra lutris kenyoni | Status Undefined | Northern Sea Otter Stock in Washington State | |
| Northern Sea Otter | Enhydra lutris kenyoni | Status Undefined | Southcentral Alaska Northern Sea Otter Stock | |
| Northern Sea Otter | Enhydra lutris kenyoni | Status Undefined | Southeast Alaska Northern Sea Otter Stock | |
| Northern Sea Otter | Enhydra lutris kenyoni | Threatened | Southwest Alaska, from Attu Island to Western Cook Inlet, including Bristol Bay, the Kodiak Archipelago, and the Barren Islands | 08-09-2005 |
| northern snakehead | Channa argus | Resolved Taxon | Wherever found | |
| Northern spotted owl | Strix occidentalis caurina | Threatened | Wherever found | 06-26-1990 |
| Northern Steptoe pyrg | Pyrgulopsis serrata | Under Review | Wherever found | |
| Northern Studfish | Fundulus catenatus | Not Listed | | |
| Northern swift fox | Vulpes velox hebes | Endangered | Canada | 06-02-1970 |
| Northern Virginia well amphipod | Stygobromus phreaticus | Resolved Taxon | Wherever found | |
| Northern water snake | Nerodia sipedon | Resolved Taxon | Upper Tidal Potomac River population | |
| Northern white rhinoceros | Ceratotherium simum cottoni | Endangered | Zaire, Uganda, Sudan, Central African Republic | 06-02-1970 |
| Northern wild monkshood | Aconitum noveboracense | Threatened | Wherever found | 05-27-1978 |
| Northern Wormwood | Artemisia campestris var. wormskioldii | Resolved Taxon | Wherever found | |
| North Pacific Right Whale | Eubalaena japonica | Endangered | Wherever found | 06-02-1970 |
| North Park phacelia | Phacelia formosula | Endangered | Wherever found | 09-01-1982 |
| North Rim primrose | Primula specuicola | Species of Concern | Wherever found | |
| Northwestern larkspur | Delphinium xantholeucum | Resolved Taxon | Wherever found | |
| Northwestern Moose | Alces alces andersoni | Resolved Taxon | Wherever found | |
| Northwestern Pond Turtle | Actinemys marmorata | Proposed Threatened | Wherever found | |
| Northwestern salamander | ambystoma gracile | Species of Concern | Wherever found | |
| Northwestern San Diego pocket mouse | chaetodipus fallax | Species of Concern | Wherever found | |
| Northwestern San Diego pocket mouse | Perognathus fallax fallax | Species of Concern | Wherever found | |
| Norton's cave amphipod | Stygobromus nortoni | Species of Concern | Wherever found | |
| Norton's cave beetle | Pseudanophthalmus nortoni | Species of Concern | Wherever found | |
| Notched Rainbow | Villosa constricta | Not Listed | | |
| notodontid moth | afilia species | Resolved Taxon | Wherever found | |
| Nudulose Coosa river snail | Elimia lachryma | Under Review | Wherever found | |
| Nueces Crayfish | Procambarus nueces | Resolved Taxon | Wherever found | |
| Nueces River shiner | Cyprinella sp. | Resolved Taxon | Wherever found | |
| Nueces Roundnose Minnow | Dionda serena | Not Listed | | |
| Nugget pebblesnail | Fluminicola seminalis | Resolved Taxon | Wherever found | |
| Numbat | Myrmecobius fasciatus | Endangered | Wherever found | 12-02-1970 |
| Nutriosa milk-vetch | Astragalus nutriosensis | Species of Concern | Wherever found | |
| Nuttall's Cornsalad | Valerianella nuttallii | Not Listed | | |
| Nuttall's micranthemum | Micranthemum micranthemoides | Species of Concern | Wherever found | |
| Nuttall's scrub oak | Quercus dumosa | Species of Concern | Wherever found | |
| Nuttall's Woodpecker | Dryobates nuttallii | Species of Concern | Wherever found | |
| Nymph elimia | Elimia porrecta | Species of Concern | Wherever found | |
| Nymph Trumpet | Phreatoceras taylori | Resolved Taxon | Wherever found | |
| Oachita pebblesnail | Somatogyrus amnicoloides | Species of Concern | Wherever found | |
| Oahu abutilon clavicoccus mealybug | Clavicoccus erinaceus | Species of Concern | Wherever found | |
| O`ahu `alauahio | Paroreomyza maculata | Endangered | Wherever found | 10-13-1970 |
| O'ahu 'Amakihi | Chlorodrepanis flava | Species of Concern | Wherever found | |
| Oahu aulu thyrocopa moth | Thyrocopa sapindiella | Species of Concern | Wherever found | |
| Oahu blackburnia ground beetle | Blackburnia insignis | Species of Concern | Wherever found | |
| Oahu capper moth | Plutella capparidis | Species of Concern | Wherever found | |
| Oahu deceptor bush cricket | Leptogryllus deceptor | Species of Concern | Wherever found | |
| Oahu elepaio | Chasiempis ibidis | Endangered | Wherever found | 04-18-2000 |
| Oahu hesperonmannia philodoria moth | Philodoria sp. | Species of Concern | Wherever found | |
| Oahu heteramphus fern weevil | Heteramphus filicum | Species of Concern | Wherever found | |
| Oahu holio gall psyllid | Paurotriozana adaptata | Species of Concern | Wherever found | |
| Oahu iliahi gall mealybug | Phyllococcus antricolens | Species of Concern | Wherever found | |
| Oahu kalanian leaf bug | Kalania sp. | Species of Concern | Wherever found | |
| Oahu ke`oke`o clavicoccus mealybug | Clavicoccus tribulus | Species of Concern | Wherever found | |
| Oahu megalagrion damselfly | Megalagrion oahuense | Species of Concern | Wherever found | |
| Oahu nesiotes weevil | Deinocossonus nesiotes | Species of Concern | Wherever found | |
| Oahu opuhe leaf mining moth | Philodoria ureraella | Species of Concern | Wherever found | |
| Oahu super long-horned beetle | Plagithmysus superstes | Species of Concern | Wherever found | |
| Oahu swamp hedyleptan moth | Hedylepta epicentra | Resolved Taxon | Wherever found | |
| Oahu tree snails | Achatinella spp. | Endangered | Wherever found | 02-12-1981 |
| Oak Creek Talussnail | Sonorella compar | Resolved Taxon | Wherever found | |
| Oak Titmouse | Baeolophus inornatus | Species of Concern | Wherever found | |
| Oasis Valley speckled dace | Rhinichthys osculus ssp. | Resolved Taxon | Oasis Valley | |
| Oasis Valley springsnail | Pyrgulopsis micrococcus | Resolved Taxon | Wherever found | |
| Obey crayfish | Cambarus obeyensis | Status Undefined | Wherever found | |
| Oblivious tiger beetle | Cicindela latesignata obliviosa | Species of Concern | Wherever found | |
| Oblong rocksnail | Leptoxis compacta | Proposed Endangered | Wherever found | |
| Obrien rhyacophilan caddisfly | Rhyacophila colonus | Species of Concern | Wherever found | |
| Obscuratan yellow-faced bee | Hylaeus obscurata | Species of Concern | Wherever found | |
| Obscure Indian paintbrush | Castilleja cryptantha | Species of Concern | Wherever found | |
| Obscure pentarthrum weevil | Pentarthrum obscura | Species of Concern | Wherever found | |
| Obsolete rhyncogonus weevil | Rhyncogonus obsoletus | Species of Concern | Wherever found | |
| Obsolete viceroy butterfly | Limenitis archippus obsoletus | Resolved Taxon | Wherever found | |
| Ocala burrowing scarab | Peltotrupes youngi | Species of Concern | Wherever found | |
| Ocala vetch | Vicia ocalensis | Resolved Taxon | Wherever found | |
| Occult little brown bat | Myotis lucifugus occultus | Species of Concern | Wherever found | |
| Occult vertigo | Vertigo occulta | Species of Concern | Wherever found | |
| Oceanic Hawaiian damselfly | Megalagrion oceanicum | Endangered | Wherever found | 10-18-2012 |
| Oceanic metromenus ground beetle | Metromenus oceanicus | Species of Concern | Wherever found | |
| Oceanic whitetip shark | Carcharhinus longimanus | Threatened | | |
| Ocelot | Leopardus (=Felis) pardalis | Endangered | wherever found | 03-28-1972 |
| Ochlockonee moccasinshell | Medionidus simpsonianus | Endangered | Wherever found | 03-16-1998 |
| Ochoco lomatium | Lomatium ochocense | Status Undefined | | |
| Ocmulgee marstonia | Marstonia agarhecta | Not Listed | Wherever found | |
| Ocmulgee marstonia | Pyrgulopsis agarhecta | Status Undefined | Wherever found | |
| Ocmulgee shiner | Cyprinella callisema | Species of Concern | Wherever found | |
| Ocmulgee skullcap | Scutellaria ocmulgee | Endangered | Wherever found | 11-29-2024 |
| Oconee crayfish ostracod | Cymocythere clavata | Species of Concern | Wherever found | |
| Ofer Hollow reedgrass | Calamagrostis porteri insperata | Species of Concern | Wherever found | |
| Ofu tree snail | Samoana thurstoni | Species of Concern | Wherever found | |
| Ogden Mountainsnail | Oreohelix peripherica wasatchensis | Resolved Taxon | Wherever found | |
| Oglethorpe oak | Quercus oglethorpensis | Resolved Taxon | Wherever found | |
| Oha | Delissea subcordata | Endangered | Wherever found | 10-10-1996 |
| Ohai | Sesbania tomentosa | Endangered | Wherever found | 11-10-1994 |
| `Oha wai | Clermontia drepanomorpha | Endangered | Wherever found | 10-10-1996 |
| `Oha wai | Clermontia lindseyana | Endangered | Wherever found | 03-04-1994 |
| `Oha wai | Clermontia oblongifolia ssp. brevipes | Endangered | Wherever found | 10-08-1992 |
| `Oha wai | Clermontia oblongifolia ssp. mauiensis | Endangered | Wherever found | 05-15-1992 |
| `Oha wai | Clermontia peleana | Endangered | Wherever found | 03-04-1994 |
| `Oha wai | Clermontia pyrularia | Endangered | Wherever found | 03-04-1994 |
| `Oha wai | Clermontia samuelii | Endangered | Wherever found | 09-03-1999 |
| `Ohe | Joinvillea ascendens ascendens | Endangered | Wherever found | 10-31-2016 |
| `Ohe | Reynoldsia sandwicensis | Resolved Taxon | Wherever found | |
| `Ohe | Tetraplasandra hawaiiensis microcarpa | Resolved Taxon | Wherever found | |
| `Ohe | Tetraplasandra kaalae multiplex | Resolved Taxon | Wherever found | |
| `Ohenaupaka oeobian moth | Oeobia dryadopa | Species of Concern | Wherever found | |
| `Ohe`ohe | Polyscias gymnocarpa | Endangered | Wherever found | 03-28-1994 |
| `Ohe`ohe | Tetraplasandra kavaiensis grandis | Resolved Taxon | Wherever found | |
| `Ohe`ohe | Tetraplasandra kavaiensis koloana | Resolved Taxon | Wherever found | |
| `Ohe`ohe | Tetraplasandra kavaiensis occidua | Resolved Taxon | Wherever found | |
| `Ohe`ohe ) | Tetraplasandra kavaiensis dipyrena | Resolved Taxon | Wherever found | |
| `Ohe`ohe e | Tetraplasandra kavaiensis intercedens | Resolved Taxon | Wherever found | |
| `Ohe`ohe leafroller | Spheterista oheoheana | Species of Concern | Wherever found | |
| `Ohe`ohe s | Tetraplasandra kavaiensis nahikuensis | Resolved Taxon | Wherever found | |
| `Ohe omoides moth | Omoides asaphombra | Species of Concern | Wherever found | |
| Ohi`a long-horned beetle | Plagithmysus pulvillatus | Species of Concern | Wherever found | |
| Ohio cave beetle | Pseudanophthalmus ohioensis | Species of Concern | Wherever found | |
| Ohio Lamprey | Ichthyomyzon bdellium | Not Listed | | |
| Ohio Pigtoe | Pleurobema cordatum | Not Listed | | |
| Ohlone tiger beetle | Cicindela ohlone | Endangered | Wherever found | 10-03-2001 |
| Ojai frtillary | Fritillaria ojaiensis | Species of Concern | Wherever found | |
| Okaloosa darter | Etheostoma okaloosae | Recovery | Wherever found | 06-04-1973 |
| Okeechobee gourd | Cucurbita okeechobeensis ssp. okeechobeensis | Endangered | | 07-12-1993 |
| Okefenokee zale moth | Zale perculta | Species of Concern | Wherever found | |
| Okinawa woodpecker | Dendrocopos noguchii | Candidate | Wherever found | |
| Oklahoma cave amphipod | Allocrangonyx pellucidus | Species of Concern | Wherever found | |
| Oklahoma cave crayfish | Cambarus tartarus | Under Review | Wherever found | |
| Oklahoma grasspink | Calopogon oklahomensis | Resolved Taxon | Wherever found | |
| Oklahoma phlox | Phlox oklahomensis | Resolved Taxon | Wherever found | |
| Oklahoma salamander | Eurycea tynerensis | Status Undefined | Wherever found | |
| Oklawaha sponge | Dosilia palmeri | Species of Concern | Wherever found | |
| Oktibbeha rivulet crayfish | Hobbseus orconectoides | Under Review | Wherever found | |
| Ola`a banana omoides moth | Omoides euryprora | Species of Concern | Wherever found | |
| `Ola`a pepppered looper | Tritocleis microphylla | Resolved Taxon | Wherever found | |
| Olaga | Opuntia borinquensis | Resolved Taxon | Wherever found | |
| Olanche Peak buckwheat | Eriogonum wrightii olanchense | Resolved Taxon | Wherever found | |
| Old birch spots | Arthopyrenia betulicola | Species of Concern | | |
| Old Blue mock pennyroyal | Hedeoma pilosum | Species of Concern | Wherever found | |
| Old gray cross-lobes | Santessoniella crossophylla | Species of Concern | | |
| Old man's beard | Clematis catesbyana | Resolved Taxon | Wherever found | |
| Old Switch Panic Grass | Panicum virgatum | Not Listed | | |
| Oliarus wild cotton planthopper | Oliarus discrepans | Species of Concern | Wherever found | |
| Olive darter | Percina squamata | Species of Concern | Wherever found | |
| Olive marstonia | Pyrgulopsis olivacea | Species of Concern | Wherever found | |
| Olive ridley sea turtle | Lepidochelys olivacea | Endangered | Breeding colony populations on Pacific coast of Mexico | 07-28-1978 |
| Olive ridley sea turtle | Lepidochelys olivacea | Threatened | Wherever found, except when listed as endangered under 50 CFR 224.101 | 07-28-1978 |
| Olive-sided Flycatcher | Contopus cooperi | Species of Concern | Wherever found | |
| Olive Warbler | Peucedramus taeniatus | Species of Concern | Wherever found | |
| Olopua rhyncogonus weevil | Rhyncogonus oleae | Species of Concern | Wherever found | |
| olua | Hypolepis hawaiiensis var. mauiensis | Endangered | Wherever found | 10-31-2016 |
| Olulu | Brighamia insignis | Endangered | Wherever found | 02-25-1994 |
| Olympia pocket gopher | Thomomys mazama pugetensis | Threatened | Wherever found | 05-09-2014 |
| Olympic harebell | Campanula piperi | Resolved Taxon | Wherever found | |
| Olympic marmot | Marmota olympus | Status Undefined | | |
| Olympic mudminnow | Novumbra hubbsi | Resolved Taxon | Wherever found | |
| Olympic pocket gopher | Thomomys mazama melanops | Resolved Taxon | Wherever found | |
| Olympic torrent salamander | Rhyacotriton olympicus | Resolved Taxon | Wherever found | |
| 'Oma'o | Myadestes obscurus | Species of Concern | Wherever found | |
| Ombrias yellow-faced bee | Hylaeus ombrias | Species of Concern | Wherever found | |
| (Omus dejeanii) ground beetle | omus dejeanii | Species of Concern | Wherever found | |
| One-awned spineflower | Chorizanthe rectispina | Species of Concern | Wherever found | |
| Oneida sponge | Spongilla heteroslerifa | Resolved Taxon | Wherever found | |
| One-spot rhyacophilan caddisfly | Rhyacophila unipunctata | Species of Concern | Wherever found | |
| One-toed Amphiuma | Amphiuma pholeter | Status Undefined | Wherever found | |
| Onondaga Cave amphipod | Stygobromus onondagaensis | Resolved Taxon | Wherever found | |
| Onthophagus tortoise commensal scarab | Onthophagus polyphemi | Species of Concern | Wherever found | |
| Onyx rocksnail | Leptoxis praerosa | Species of Concern | Wherever found | |
| O`opu alamo`o | Lentipes concolor | Species of Concern | Wherever found | |
| `Opae Kala`Ole (Hawaiian Spineless Shrimp) | Atyoida bisulcata | Not Listed | | |
| Opaque pebblesnail | Somatogyrus tennesseensis | Species of Concern | Wherever found | |
| Opler's longhorn moth | Adella oplerella | Resolved Taxon | Wherever found | |
| Opossum Pipefish | Microphis brachyurus | Not Listed | | |
| Opposite-leaved lewisia | Lewisia oppositifolia | Resolved Taxon | Wherever found | |
| Opuhe | Urera kaalae | Endangered | Wherever found | 10-29-1991 |
| Opuhe gall mealybug | Phyllococcus oahuensis | Species of Concern | Wherever found | |
| Orange-bellied parakeet | Neophema chrysogaster | Endangered | Wherever found | 12-02-1970 |
| Orangebelly Darter | Etheostoma radiosum | Not Listed | | |
| Orangeblack Hawaiian damselfly | Megalagrion xanthomelas | Endangered | Wherever found | 10-31-2016 |
| Orangefin madtom | Noturus gilberti | Under Review | Wherever found | |
| Orangefoot pimpleback (pearlymussel) | Plethobasus cooperianus | Endangered | Wherever found | 06-14-1976 |
| Orangefoot pimpleback (pearlymussel) | Plethobasus cooperianus | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Orange-fronted parakeet | Cyanoramphus malherbi | Candidate | Wherever found | |
| Orange Lake Cave crayfish | Procambarus franzi | Under Review | Wherever found | |
| Orange lupine | Lupinus citrinus | Species of Concern | Wherever found | |
| Orangenacre mucket | Hamiota perovalis | Threatened | Wherever found | 03-17-1993 |
| Orangespotted sunfish | Lepomis humilis | Not Listed | | |
| Orangetail Shiner | Pteronotropis merlini | Not Listed | | |
| Orange-throated whiptail | Cnemidophorus hyperythrus | Species of Concern | Wherever found | |
| Orangutan | Pongo pygmaeus | Endangered | Wherever found | 06-02-1970 |
| Orchard Oriole | Icterus spurius | Species of Concern | Wherever found | |
| Orcutt's bird's-beak | Cordylanthus orcuttianus | Species of Concern | Wherever found | |
| Orcutt's brodiaea | Brodiaea orcuttii | Species of Concern | Wherever found | |
| Orcutt's dudleya | Dudleya attentuata orcuttii | Species of Concern | Wherever found | |
| Orcutt's hazardia | Hazardia orcuttii | Resolved Taxon | Wherever found | |
| Orcutt's linanthus | Linanthus orcuttii | Species of Concern | Wherever found | |
| Orcutt's quillwort | Isoetes orcuttii | Resolved Taxon | Wherever found | |
| Orcutt's spineflower | Chorizanthe orcuttiana | Endangered | Wherever found | 10-07-1996 |
| Oreganillo | Koanophyllon droserolepis | Species of Concern | Wherever found | |
| Oregon cave amphipod | Stygobromus oregonensis | Resolved Taxon | Wherever found | |
| Oregon chub | Oregonichthys crameri | Recovery | Wherever found | 10-18-1993 |
| Oregon dolophilodes caddisfly | Dolophilodes oregonus | Resolved Taxon | Wherever found | |
| Oregon fireweed | Epilobium oreganum | Species of Concern | Wherever found | |
| Oregon Floater | Anodonta oregonensis | Not Listed | | |
| Oregon giant earthworm | Megascolides macelfreshi | Species of Concern | Wherever found | |
| Oregon megomphix | megomphix hemphilli | Species of Concern | Wherever found | |
| Oregon rock-cress | Arabis oregana | Resolved Taxon | Wherever found | |
| Oregon semaphore grass | Pleuropogon oregonus | Species of Concern | Wherever found | |
| Oregon silverspot butterfly | Speyeria zerene hippolyta | Experimental Population, Non-Essential | | 06-23-2017 |
| Oregon silverspot butterfly | Speyeria zerene hippolyta | Threatened | Wherever found | 07-02-1980 |
| Oregon slender salamander | Batrachoseps wrighti | Status Undefined | Wherever found | |
| Oregon spotted frog | Rana pretiosa | Threatened | Wherever found | 09-29-2014 |
| Oregon Vesper Sparrow | Pooecetes gramineus affinis | Under Review | Wherever found | |
| Oregon woodsia | Woodsia oregana cathcartiana | Species of Concern | Wherever found | |
| Organ Cave pseudoscorpion | Kleptochthonius hetricki | Species of Concern | Wherever found | |
| Organ Mountain evening-primrose | Oenothera organensis | Species of Concern | Wherever found | |
| Organ Mountain figwort | Scrophularia laevis | Species of Concern | Wherever found | |
| Organ Mountains Colorado chipmunk | Eutamias quadrivittatus australis | Species of Concern | Wherever found | |
| Oriental white stork | Ciconia boyciana (=ciconia b.) | Endangered | Wherever found | 06-02-1970 |
| Orinoco crocodile | Crocodylus intermedius | Endangered | Wherever found | 06-02-1970 |
| Orlando Cave crayfish | Procambarus acherontis | Under Review | Wherever found | |
| Ornate rocksnail | Lithasia geniculata | Species of Concern | Wherever found | |
| Orocopia sage | Salvia greatai | Species of Concern | Wherever found | |
| Orpheus cave pseudoscorpion | Kleptochthonius orpheus | Species of Concern | Wherever found | |
| Osgood Mountains milk-vetch | Astragalus yoder-williamsii | Resolved Taxon | Wherever found | 08-13-1980 |
| Oso Flaco flightless moth | Areniscythris brachypteris | Species of Concern | Wherever found | |
| Oso Flaco patch butterfly | Chlosyne leanira osoflaco | Species of Concern | Wherever found | |
| Oso Flaco robber fly | Ablautus schlingeri | Species of Concern | Wherever found | |
| Oso manzanita | Arctostaphylos osoensis | Species of Concern | Wherever found | |
| osprey | Pandion haliaetus | Species of Concern | Wherever found | |
| Osterhout milkvetch | Astragalus osterhoutii | Endangered | Wherever found | 07-13-1989 |
| Ostler's peppergrass | Lepidium ostleri | Resolved Taxon | Wherever found | |
| Ostlund wild-buckwheat | Eriogonum ostlundii | Resolved Taxon | Wherever found | |
| Otay lotus | Lotus crassifolius otayensis | Species of Concern | Wherever found | |
| Otay manzanita | Arctostaphylos otayensis | Species of Concern | Wherever found | |
| Otay mesa-mint | Pogogyne nudiuscula | Endangered | Wherever found | 08-03-1993 |
| Otay tarplant | Deinandra (=Hemizonia) conjugens | Threatened | Wherever found | 10-13-1998 |
| Otter Creek Pyrg | Pyrgulopsis fusca | Resolved Taxon | Wherever found | |
| Ouachita burrowing crayfish | Fallicambarus harpi | Status Undefined | Wherever found | |
| Ouachita creekshell | Villosa arkansasensis | Resolved Taxon | Wherever found | |
| Ouachita dusky salamander | Desmognathus brimleyorum | Species of Concern | Wherever found | |
| Ouachita fanshell | Cyprogenia sp. cf. aberti | Threatened | | 07-27-2023 |
| Ouachita kidneyshell | Ptychobranchus occidentalis | Species of Concern | Wherever found | |
| Ouachita madtom | Noturus lachneri | Status Undefined | Wherever found | |
| Ouachita Mantleslug | Pallifera tournescalis | Resolved Taxon | Wherever found | |
| Ouachita Mountain shiner | Lythrurus snelsoni | Species of Concern | Wherever found | |
| Ouachita rock pocketbook | Arcidens wheeleri | Endangered | Wherever found | 10-23-1991 |
| `O`u (honeycreeper) | Psittirostra psittacea | Endangered | Wherever found | 03-11-1967 |
| Oval-leaved snapdragon | Howelliella ovata | Resolved Taxon | Wherever found | |
| Oval pigtoe | Pleurobema pyriforme | Endangered | Wherever found | 03-16-1998 |
| Ovate clubshell | Pleurobema perovatum | Endangered | Wherever found | 03-17-1993 |
| Ovate pebblesnail | Somatogyrus excavatus | Species of Concern | Wherever found | |
| Ovate vertigo | Vertigo ovata | Species of Concern | Wherever found | |
| Overlooked cave beetle | Pseudanophthalmus praetermissus | Resolved Taxon | Wherever found | |
| Owens Or Lahontan Speckled Dace | Rhinichthys osculus robustus | Not Listed | | |
| Owens Peak lomatium | Lomatium shevockii | Species of Concern | Wherever found | |
| Owens pupfish | Cyprinodon radiosus | Endangered | Wherever found | 03-11-1967 |
| Owens speckled dace | Rhinichthys osculus ssp. | Species of Concern | Owens | |
| Owens springsnail | Pyrgulopsis owensensis | Species of Concern | Wherever found | |
| Owens Sucker | Catostomus fumeiventris | Not Listed | | |
| Owens Tui Chub | Gila bicolor ssp. snyderi | Endangered | Wherever found | 08-05-1985 |
| Owens Valley California vole | Microtus californicus vallicola | Species of Concern | Wherever found | |
| Owens Valley checkermallow | Sidalcea covillei | Resolved Taxon | Wherever found | |
| Owens Valley web-toes salamander | Hydromantes sp. | Species of Concern | Wherever found | |
| Ownbey's thistle | Cirsium ownbeyi | Species of Concern | Wherever found | |
| Owyhee clover | Trifolium owyheense | Species of Concern | Wherever found | |
| Owyhee hot springsnail | Pyrgulopsis fresti | Status Undefined | | |
| Owyhee upland pyrg | Pyrgulopsis owyheensis | Status Undefined | | |
| Oyster mussel | Epioblasma capsaeformis | Endangered | Wherever found; Except where listed as Experimental Populations | 01-10-1997 |
| Oyster mussel | Epioblasma capsaeformis | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Oyster mussel | Epioblasma capsaeformis | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Ozark big-eared bat | Corynorhinus (=Plecotus) townsendii ingens | Endangered | Wherever found | 11-30-1979 |
| Ozark cave amphipod | Stygobromus ozarkensis | Resolved Taxon | Wherever found | |
| Ozark cavefish | Amblyopsis rosae | Threatened | Wherever found | 11-01-1984 |
| Ozark chinquapin | Castanea pumila ozarkensis | Resolved Taxon | Wherever found | |
| Ozark chub | Erimystax harryi | Resolved Taxon | Wherever found | |
| Ozark emerald | Somatochlora ozarkensis | Status Undefined | Wherever found | |
| Ozark Hellbender | Cryptobranchus alleganiensis bishopi | Endangered | Wherever found | 11-07-2011 |
| Ozark Minnow | Notropis nubilus | Not Listed | | |
| Ozark Pigtoe | Fusconaia ozarkensis | Not Listed | | |
| Ozark pyrg | Pyrgulopsis ozarkensis | Resolved Taxon | Wherever found | |
| Ozark shiner | Notropis ozarcanus | Under Review | Wherever found | |
| Ozark snaketail | Ophiogomphus westfalli | Species of Concern | Wherever found | |
| Pacific Black Duck | Anas superciliosa | Species of Concern | | |
| Pacific Black Duck | Anas superciliosa pelewensis | Species of Concern | | |
| Pacific bleeding-heart | Dicentra formosa oregana | Resolved Taxon | Wherever found | |
| Pacific giant salamander | dicamptodon tenebrosus | Species of Concern | Wherever found | |
| Pacific Golden-Plover | Pluvialis fulva | Species of Concern | | |
| Pacific Grove clover | Trifolium variegatum | Resolved Taxon | Wherever found | |
| Pacific Hawaiian damselfly | Megalagrion pacificum | Endangered | Wherever found | 07-26-2010 |
| Pacific Herring | Clupea pallasii | Not Listed | | |
| Pacific Imperial Pigeon | Ducula pacifica pacifica | Species of Concern | | |
| Pacific lamprey | lampetra tridentata | Species of Concern | Wherever found | |
| Pacific lamprey | Lampetra tridentata ssp. | Resolved Taxon | Pacific | |
| Pacific Lamprey | Entosphenus tridentatus | Not Listed | | |
| Pacific manzanita | Arctostaphylos pacifica | Resolved Taxon | Wherever found | |
| Pacific Marten, Coastal Distinct Population Segment | Martes caurina | Threatened | Wherever found | 11-09-2020 |
| Pacific pocket mouse | Perognathus longimembris pacificus | Endangered | Wherever found | 02-03-1994 |
| Pacific Red Snapper | Lutjanus peru | Not Listed | | |
| Pacific River Goby, `O`Opu Nakea | Awaous guamensis | Not Listed | | |
| Pacific sheath-tailed Bat | Emballonura semicaudata rotensis | Endangered | Wherever found | 11-02-2015 |
| Pacific sheath-tailed Bat | Emballonura semicaudata semicaudata | Endangered | American Samoa | 10-24-2016 |
| Pacific Sideband | Monadenia fidelis | Not Listed | | |
| Pacific slope Flycatcher | Empidonax difficilis | Species of Concern | Wherever found | |
| Pacific Staghorn Sculpin | Leptocottus armatus | Not Listed | | |
| Pacific Townsend's big-eared bat | Plecotus townsendii townsendii | Species of Concern | Wherever found | |
| Pacific walrus | Odobenus rosmarus ssp. divergens | Resolved Taxon | Wherever found | |
| Pacific yew | Taxus brevifolia | Resolved Taxon | Wherever found | |
| Packard's cave amphipod | Crangonyx packardi | Resolved Taxon | Wherever found | |
| Packard's milkvetch | Astragalus cusickii var. packardiae | Resolved Taxon | Wherever found | |
| Packard's stickleaf | Mentzelia packardiae | Resolved Taxon | Wherever found | |
| Paddlefish | Polyodon spathula | Resolved Taxon | Wherever found | |
| Pagan Mariana flying fox bat | Pteropus mariannus paganensis | Species of Concern | Wherever found | |
| Page Spring micro caddisfly | Metrichia volada | Species of Concern | Wherever found | |
| Page springsnail | Pyrgulopsis morrisoni | Resolved Taxon | Wherever found | |
| Pagi Island langur | Nasalis concolor | Endangered | Wherever found | 06-02-1970 |
| Pagoda slitshell | Gyrotoma pagoda | Resolved Taxon | Wherever found | |
| Pagosa skyrocket | Ipomopsis polyantha | Endangered | Wherever found | 08-26-2011 |
| Pahasapa mountainsnail | Oreohelix strigosa ssp. | Species of Concern | Wherever found | |
| Pahranagat pebblesnail | Pyrgulopsis merriami | Resolved Taxon | Wherever found | |
| Pahranagat roundtail chub | Gila robusta jordani | Endangered | Wherever found | 10-13-1970 |
| Pahranagat speckled dace | Rhinichthys osculus velifer | Resolved Taxon | Wherever found | |
| Pahranagat spinedace | Lepidomeda altivelis | Resolved Taxon | Wherever found | |
| Pahranagat Valley montane vole | Microtus montanus fucosus | Species of Concern | Wherever found | |
| Pahrump Killifish | Empetrichthys latos latos | Not Listed | | |
| Pahrump poolfish | Empetrichthys latos | Endangered | Wherever found | 03-11-1967 |
| Pa`iniu | Astelia veratroides gracilis | Resolved Taxon | Wherever found | |
| Pa`iniu | Astelia veratroides macrosperma | Resolved Taxon | Wherever found | |
| Pa`iniu | Astelia veratroides veratroides | Resolved Taxon | Wherever found | |
| Pa`iniu | Astelia waialealae | Endangered | Wherever found | 05-13-2010 |
| Painted Bunting | Passerina ciris | Species of Concern | Wherever found | |
| Painted clubshell | Pleurobema chattanoogaense | Resolved Taxon | Wherever found | |
| Painted Creekshell | Villosa taeniata | Not Listed | | |
| Painted rocksnail | Leptoxis taeniata | Threatened | Wherever found | 10-28-1998 |
| Painted snake coiled forest snail | Anguispira picta | Threatened | Wherever found | 08-02-1978 |
| Painted woolly bat | Kerivoula picta | Status Undefined | | |
| Paiute cutthroat trout | Oncorhynchus clarkii seleniris | Threatened | Wherever found | 03-11-1967 |
| Paiute cypress | Callitropsis nevadensis | Resolved Taxon | Wherever found | |
| Paiute sculpin | Cottus beldingii | Status Undefined | Wherever found | |
| Pajarito southern pocket gopher | Thomomys umbrinus quercinus | Species of Concern | Wherever found | |
| Pajaroensis manzanita | Arctostaphylos pajaroensis | Species of Concern | Wherever found | |
| Pakistan sand cat | Felis margarita scheffeli | Endangered | Wherever found | 01-23-1984 |
| Palai la`au | Adenophorus periens | Endangered | Wherever found | 11-10-1994 |
| Palapalai aumakua | Dryopteris crinalis var. podosorus | Endangered | Wherever found | 05-13-2010 |
| Palatka skipper | Euphyes pilatka klotsi | Under Review | Wherever found | |
| Palau blue-faced parrotfinch | Erythrura trichroa pelewensis | Resolved Taxon | Wherever found | |
| Palau fantail flycatcher | Rhipidura lepida | Recovery | Wherever found | 06-02-1970 |
| Palau ground dove | Gallicolumba canifrons | Recovery | Wherever found | 06-02-1970 |
| Palau Nicobar pigeon | Caloenas nicobarica pelewensis | Resolved Taxon | Wherever found | |
| Palau Owl | Pyrroglaux podargina | Recovery | Wherever found | 06-02-1970 |
| Palau white-breasted wood-swallow | Artamus leucorhynchus pelewensis | Pre-Act Delisted Taxon | Wherever found | |
| Palawan peacock pheasant | Polyplectron emphanum | Endangered | Wherever found | 06-02-1970 |
| Paleback darter | Etheostoma pallididorsum | Not Listed | Wherever found | |
| Pale blue-eyed grass | Sisyrinchium pallidum | Species of Concern | Wherever found | |
| Pale cave beetle | Pseudanophthalmus pallidus | Species of Concern | Wherever found | |
| Pale lilliput (pearlymussel) | Toxolasma cylindrellus | Endangered | Wherever found | 06-14-1976 |
| Pale phacelia | Phacelia pallida | Species of Concern | Wherever found | |
| Pale poppy | Papaver alboroseum | Resolved Taxon | Wherever found | |
| Pale Townsend's big-eared bat | Plecotus townsendii pallescens | Species of Concern | Wherever found | |
| Pale-yellow layia | Layia heterotricha | Species of Concern | Wherever found | |
| Pale yellow lupine | Lupinus luteolus | Species of Concern | Wherever found | |
| Pale yellow stonecrop | Sedum laxum flavidum | Resolved Taxon | Wherever found | |
| Palezone shiner | Notropis albizonatus | Endangered | Wherever found | 04-27-1993 |
| Palila (honeycreeper) | Loxioides bailleui | Endangered | Wherever found | 03-11-1967 |
| Pallid bat | antrozous pallidus | Species of Concern | Wherever found | |
| Pallid birds-beak | Cordylanthus tenuis pallescens | Species of Concern | Wherever found | |
| Pallid Cave crayfish | Procambarus pallidus | Under Review | Wherever found | |
| Pallid manzanita | Arctostaphylos pallida | Threatened | Wherever found | 04-22-1998 |
| Pallid Mountainsnail | Oreohelix hendersoni | Resolved Taxon | Wherever found | |
| Pallid oldfield beach mouse | Peromyscus polionotus decoloratus | Resolved Taxon | Wherever found | |
| Pallid San Diego pocket mouse | Perognathus fallax pallidus | Species of Concern | Wherever found | |
| Pallid Shiner | Hybopsis amnis | Not Listed | | |
| Pallid sturgeon | Scaphirhynchus albus | Endangered | Wherever found | 09-06-1990 |
| Pallipes eopenthes click beetle | Eopenthes pallipes | Species of Concern | Wherever found | |
| Palma de manaca | Calyptronoma rivalis | Threatened | Wherever found | 02-06-1990 |
| Palmate-bracted bird's beak | Cordylanthus palmatus | Endangered | Wherever found | 07-01-1986 |
| Palmer's bush-mallow | Malacothamnus palmeri palmeri | Resolved Taxon | Wherever found | |
| Palmer's chipmunk | Tamias palmeri | Species of Concern | Wherever found | |
| Palmer's Curve-billed Thrasher | Toxostoma curvirostre palmeri | Species of Concern | | |
| Palmer's goldenbush | Ericameria palmeri ssp. palmeri | Status Undefined | Wherever found | |
| Palmer's grapplinghook | Harpagonella palmeri | Species of Concern | Wherever found | |
| Palmer's grapplinghook | Harpagonella palmeri palmeri | Species of Concern | Wherever found | |
| Palmer's haplopappus | Haplopappus palmeri palmeri | Species of Concern | Wherever found | |
| Palmer's mariposa lily | Calochortus palmeri palmeri | Species of Concern | Wherever found | |
| Palmer's monardella | Monardella palmeri | Resolved Taxon | Wherever found | |
| Palmetto pillsnail | Euchemotrema cheatumi | Species of Concern | Wherever found | |
| Palm Springs little pocket mouse | Perognathus longimembris bangsi | Not Listed | Wherever found | |
| Palm Springs round-tailed ground (=Coachella Valley) Squirrel | Spermophilus tereticaudus chlorus | Resolved Taxon | Wherever found | |
| Palo colorado | Ternstroemia luquillensis | Endangered | Wherever found | 04-22-1992 |
| Palo de jazmin | Styrax portoricensis | Endangered | Wherever found | 04-22-1992 |
| Palo de nigua | Cornutia obovata | Endangered | Wherever found | 04-07-1988 |
| Palo de ramon | Banara vanderbiltii | Endangered | Wherever found | 01-14-1987 |
| Palo de rosa | Ottoschulzia rhodoxylon | Threatened | Wherever found | 04-10-1990 |
| Palo de violeta | Polygala cowellii | Resolved Taxon | Wherever found | |
| Palo Duro mouse | Peromyscus truei comanche | Species of Concern | Wherever found | |
| Palomar monkeyflower | mimulus diffusus | Species of Concern | Wherever found | |
| Palomas pupfish | Cyprinodon | Species of Concern | Wherever found | |
| Palos Verdes blue butterfly | Glaucopsyche lygdamus palosverdesensis | Endangered | Wherever found | 07-02-1980 |
| Pamakani | Tetramolopium capillare | Endangered | Wherever found | 09-30-1994 |
| Pamakani | Viola chamissoniana ssp. chamissoniana | Endangered | Wherever found | 10-29-1991 |
| Pampas deer | Ozotoceros bezoarticus | Endangered | Wherever found | 06-14-1976 |
| Panama City crayfish | Procambarus econfinae | Threatened | Wherever found | 02-04-2022 |
| Panamanian golden frog | Atelopus varius zeteki | Endangered | Wherever found | 06-14-1976 |
| Panamanian jaguarundi | Herpailurus (=Felis) yagouaroundi panamensis | Endangered | Wherever found | 06-14-1976 |
| Panamint alligator lizard | Elgaria panamintina | Resolved Taxon | Wherever found | |
| Panamint daisy | Enceliopsis covillei | Species of Concern | Wherever found | |
| Panamint dudleya | Dudleya saxosa saxosa | Species of Concern | Wherever found | |
| Panamint Mountains buckwheat | Eriogonum microthecum panamintense | Species of Concern | Wherever found | |
| Panamint Mountains lupine | Lupinus magnificus magnificus | Species of Concern | Wherever found | |
| panaunau | lobelia yuccoides | Species of Concern | Wherever found | |
| Pandanus skink | Aulacoplax leptosoma | Resolved Taxon | Wherever found | |
| Panguitch wild-buckwheat | Eriogonum panguicense alpestre | Resolved Taxon | Wherever found | |
| Panhandle lily | Lilium iridollae | Not Listed | | |
| Panhandle meadowbeauty | Rhexia salicifolia | Not Listed | | |
| Panhandle pebblesnail | Somatogyrus virginicus | Species of Concern | Wherever found | |
| Panoche peppergrass | Lepidium jaredii album | Species of Concern | Wherever found | |
| Papala | Charpentiera densiflora | Endangered | Wherever found | 05-13-2010 |
| Paper-spined cactus | Sclerocactus papyracanthus | Species of Concern | Wherever found | |
| Papery whitlow-wort | Paronychia chartacea | Threatened | | 01-21-1987 |
| Papillose taildropper | prophysaon dubium | Species of Concern | Wherever found | |
| Pappose spikeweed | Hemizonia parryi congdonii | Species of Concern | Wherever found | |
| Parachute beardtongue | Penstemon debilis | Threatened | Wherever found | 08-26-2011 |
| Paradise parakeet | Psephotus pulcherrimus | Endangered | Wherever found | 12-02-1970 |
| Paraguana Mustached Bat | Pteronotus paraguanensis | Under Review | Wherever found | |
| Parasitic Jaeger | Stercorarius parasiticus | Species of Concern | | |
| Parasol clover | Trifolium bolanderi | Species of Concern | Wherever found | |
| Paria spurge | Euphorbia nephradenia | Resolved Taxon | Wherever found | |
| Paria sunflower | Heliomeris soliceps | Resolved Taxon | Wherever found | |
| Pariette cactus | Sclerocactus brevispinus | Threatened | Wherever found | 09-15-2009 |
| Parish's alkali grass | Puccinellia parishii | Resolved Taxon | Wherever found | |
| Parish's bush-mallow | Malacothamnus parishii | Species of Concern | Wherever found | |
| Parish's chaenactis | Chaenactis parishii | Resolved Taxon | Wherever found | |
| Parish's checkerbloom | Sidalcea hickmanii parishii | Resolved Taxon | Wherever found | |
| Parish's daisy | Erigeron parishii | Threatened | Wherever found | 08-24-1994 |
| Parish's gooseberry | Ribes divaricatum parishii | Species of Concern | Wherever found | |
| Parish's meadowfoam | Limnanthes gracilis parishii | Resolved Taxon | Wherever found | |
| Parish's phacelia | Phacelia parishii | Species of Concern | Wherever found | |
| Parish's rock-cress | Arabis parishii | Species of Concern | Wherever found | |
| Parker's pipewort | Eriocaulon parkeri | Resolved Taxon | Wherever found | |
| Parker's riffle beetle | Cylloepus parkeri | Resolved Taxon | Wherever found | |
| Parkhill Prairie Crayfish | Procambarus steigmani | Resolved Taxon | Wherever found | |
| Parkinson's black petrel | Procellaria parkinsoni | Resolved Taxon | Wherever found | |
| Park rock-cress | Arabis vivariensis | Species of Concern | Wherever found | |
| Parks' jointweed | Polygonella parksii | Resolved Taxon | Wherever found | |
| Parma wallaby | Macropus parma | Endangered | Wherever found | 12-02-1970 |
| Parrish crayfish | Cambarus parrishi | Status Undefined | Wherever found | |
| Parrish's brittlescale | Atriplex parishii | Species of Concern | Wherever found | |
| Parrot pitcher-plant | Sarracenia psittacina | Resolved Taxon | Wherever found | |
| Parry's horkelia | Horkelia parryi | Species of Concern | Wherever found | |
| Parry's spineflower | Chorizanthe parryi parryi | Species of Concern | Wherever found | |
| Parry's tetracoccus | Tetracoccus dioicus | Species of Concern | Wherever found | |
| Pascagoula map turtle | Graptemys gibbonsi | Similarity of Appearance (Threatened) | Wherever found | |
| Passey's onion | Allium passeyi | Resolved Taxon | Wherever found | |
| patagonia eyed silkmoth | Automeris patagoniensis | Resolved Taxon | Wherever found | |
| Patch-nosed salamander | Urspelerpes brucei | Status Undefined | Wherever found | |
| Patruelis oechalia stink bug | Oechalia patruelis | Species of Concern | Wherever found | |
| Paudedo | Hedyotis megalantha | Endangered | Wherever found | 11-02-2015 |
| Pauoa | Ctenitis squamigera | Endangered | Wherever found | 09-26-1994 |
| Pauper milk-vetch | Astragalus misellus pauper | Resolved Taxon | Wherever found | |
| Pawnee montane skipper | Hesperia leonardus montana | Threatened | Wherever found | 09-25-1987 |
| Payne's cave beetle | Pseudanophthalmus paynei | Species of Concern | Wherever found | |
| Payson beardtongue | Penstemon paysoniorum | Resolved Taxon | Wherever found | |
| Payson's jewelflower | Caulanthus simulans | Species of Concern | Wherever found | |
| Peach-leaved willow | Salix amygdaloides | Status Undefined | Wherever found | |
| Peacock larkspur | Delphinium pavonaceum | Resolved Taxon | Wherever found | |
| Peacock softshell turtle | Trionyx hurum | Endangered | Wherever found | 06-14-1976 |
| Peaks of Otter salamander | Plethodon hubrichti | Resolved Taxon | Wherever found | |
| Peamouth | Mylocheilus caurinus | Not Listed | | |
| Peanut sandwort | Minuartia rosei | Resolved Taxon | Wherever found | |
| Pearl Dace | Margariscus margarita | Not Listed | | |
| Pearl darter | Percina aurora | Threatened | Wherever found | 10-20-2017 |
| Pearl River Map Turtle | Graptemys pearlensis | Threatened | | 08-12-2024 |
| Peary caribou | Rangifer tarandus pearyi | Resolved Taxon | Wherever found | |
| Pecatonica River mayfly | Acanthometropus pecatonica | Species of Concern | Wherever found | |
| Pecho manzanita | Arctostaphylos pechoensis | Species of Concern | Wherever found | |
| Peck's cave amphipod | Stygobromus (=Stygonectes) pecki | Endangered | Wherever found | 12-18-1997 |
| Peck's lomatium | Lomatium peckianum | Resolved Taxon | Wherever found | |
| Peck's sanicle | Sanicula peckiana | Resolved Taxon | Wherever found | |
| Pecos amphipod | Gammarus pecos | Endangered | Wherever found | 07-09-2013 |
| Pecos assiminea snail | Assiminea pecos | Endangered | Wherever found | 08-09-2005 |
| Pecos bluntnose shiner | Notropis simus pecosensis | Threatened | Wherever found | 02-20-1987 |
| Pecos gambusia | Gambusia nobilis | Endangered | Wherever found | 10-13-1970 |
| Pecos pupfish | Cyprinodon pecosensis | Proposed Threatened | Wherever found | |
| Pecos (=puzzle, =paradox) sunflower | Helianthus paradoxus | Threatened | Wherever found | 10-20-1999 |
| Pecos River muskrat | Ondatra zibethicus ripensis | Species of Concern | Wherever found | |
| Pecos springsnail | Pyrgulopsis pecosensis | Under Review | Wherever found | |
| Pectoral Sandpiper | Calidris melanotos | Species of Concern | Wherever found | |
| Pedate checker-mallow | Sidalcea pedata | Endangered | Wherever found | 08-31-1984 |
| Pedernales Oval | Patera leatherwoodi | Resolved Taxon | Wherever found | |
| Pedernales River Springs salamander | Eurycea species | Under Review | Wherever found | |
| Pederseni''s Tiger Spider | Poecilotheria vittata | Endangered | Wherever found | 08-30-2018 |
| Peebles Navajo cactus | Pediocactus peeblesianus ssp. peeblesianus | Endangered | Wherever found | 11-28-1979 |
| Pee Dee crayfish ostracod | Dactylocythere peedeensis | Species of Concern | Wherever found | |
| Pee Dee lotic crayfish | Procambarus lepidodactylus | Species of Concern | Wherever found | |
| Peirson's aster | Oreostemma peirsonii | Resolved Taxon | Wherever found | |
| Peirson's lupine | Lupinus peirsonii | Resolved Taxon | Wherever found | |
| Peirson's milk-vetch | Astragalus magdalenae var. peirsonii | Threatened | Wherever found | 10-06-1998 |
| Peirson's morning-glory | Calystegia peirsonii | Species of Concern | Wherever found | |
| Peirson's spring beauty | Claytonia lanceolata peirsonii | Species of Concern | Wherever found | |
| Pelagic Cormorant | Phalacrocorax pelagicus pelagicus | Species of Concern | Wherever found | |
| Pele megalagrion damselfly | Megalagrion amaurodytum peles | Species of Concern | Wherever found | |
| Pele yellow-faced bee | Nesoprosopis pele | Resolved Taxon | Wherever found | |
| Pelos del diablo | Aristida portoricensis | Endangered | Wherever found | 08-08-1990 |
| Pelzeln's gazelle | Gazella dorcas pelzelni | Endangered | Wherever found | 07-27-1979 |
| Penasco least chipmunk | Tamias minimus atristriatus | Endangered | Wherever found | 01-09-2025 |
| Pendleton button-clery | Eryngium pendletonensis | Status Undefined | Wherever found | |
| Peninsula Coast Range shoulderband | Helminthoglypta nickliniana awania | Species of Concern | Wherever found | |
| Peninsular beargrass | Nolina cismontana | Species of Concern | Wherever found | |
| Peninsular bighorn sheep | Ovis canadensis nelsoni | Endangered | U.S.A. (CA) Peninsular Ranges | 03-18-1998 |
| Peninsular pronghorn | Antilocapra americana peninsularis | Endangered | Mexico (Baja California) | 10-28-1975 |
| Peninsular Range shoulderband | Helminthoglypta traski coelata | Species of Concern | Wherever found | |
| Penland alpine fen mustard | Eutrema penlandii | Threatened | | 07-28-1993 |
| Penland beardtongue | Penstemon penlandii | Endangered | Wherever found | 07-13-1989 |
| Pennell's bird's-beak | Cordylanthus tenuis ssp. capillaris | Endangered | Wherever found | 02-03-1995 |
| Pennsylvania sponge | Heteromeyenia longistylis | Resolved Taxon | Wherever found | |
| Penobscot meadow vole | Microtus pennsylvanicus shattucki | Species of Concern | Wherever found | |
| Peppered chub | Macrhybopsis tetranema | Endangered | Wherever found | 03-30-2022 |
| Peppered shiner | Notropis perpallidus | Under Review | Wherever found | |
| Perdido Key beach mouse | Peromyscus polionotus trissyllepsis | Endangered | Wherever found | 06-06-1985 |
| Peregrine Falcon | Falco peregrinus | Species of Concern | Wherever found | |
| Perennial caltrop | Kallstroemia perennans | Resolved Taxon | Wherever found | |
| Perennial spurge | Chamaesyce perennans | Resolved Taxon | Wherever found | |
| Perkin's club-palp bristletail | Machiloides perkinsi | Species of Concern | Wherever found | |
| Perkins' nesomimesan sphecid wasp | Nesomimesa perkinsi | Species of Concern | Wherever found | |
| Perkins' oceanides seed bug | Oceanides perkinsi | Species of Concern | Wherever found | |
| Perkin's yellow-faced bee | Hylaeus perkinsianus | Species of Concern | Wherever found | |
| Persian fallow deer | Dama mesopotamica (=dama m.) | Endangered | Wherever found | 06-02-1970 |
| Persian Sturgeon | Acipenser persicus | Proposed Endangered | Wherever found | |
| Persistent trillium | Trillium persistens | Endangered | Wherever found | 05-27-1978 |
| Perspicuan yellow-faced bee | Hylaeus perspicuus | Resolved Taxon | Wherever found | |
| Peruvian plantcutter | Phytotoma raimondii | Endangered | Wherever found | 07-24-2012 |
| Petaluma popcornflower | Plagiobothrys mollis vestitus | Species of Concern | Wherever found | |
| Peter's Mountain mallow | Iliamna corei | Endangered | Wherever found | 05-12-1986 |
| Petites Graines camasey | Graffenrieda ottoschulzii | Species of Concern | Wherever found | |
| Petrunkevitch's cave beetle | Pseudanophthalmus petrunkevitchi | Species of Concern | Wherever found | |
| Phainopepla | Phainopepla nitens | Species of Concern | Wherever found | |
| Phainopepla | Phainopepla nitens lepida | Species of Concern | | |
| Phantom shiner | Notropis orca | Resolved Taxon | Wherever found | |
| Phantom Springsnail | Pyrgulopsis texana | Endangered | Wherever found | 08-08-2013 |
| Phantom Tryonia | Tryonia cheatumi | Endangered | Wherever found | 07-09-2013 |
| pheasantshell | Ortmanniana pectorosa | Status Undefined | | |
| Pheres blue | Icaricia icarioides pheres | Resolved Taxon | Wherever found | |
| Philadelphia panic grass | Panicum philadelphicum | Resolved Taxon | Wherever found | |
| Philippine cockatoo | Cacatua haematuropygia | Endangered | Wherever found | 06-24-2014 |
| Philippine crocodile | Crocodylus novaeguineae mindorensis | Endangered | Wherever found | 06-14-1976 |
| Philippine eagle | Pithecophaga jefferyi | Endangered | Wherever found | 06-02-1970 |
| Philippine pangolin | Manis culionensis | Under Review | Wherever found | |
| Philippine tarsier | Tarsius syrichta | Threatened | Wherever found | 10-19-1976 |
| Phleophagan chestnut nepticulid moth | Ectodemia phleophaga | Species of Concern | Wherever found | |
| Phoenix Petrel | Pterodroma alba | Species of Concern | Wherever found | |
| Phoenix talussnail | Maricopella allynsmithi | Under Review | Wherever found | |
| Phyllostegian leaf bug | Cyrtopeltis phyllostegiae | Resolved Taxon | Wherever found | |
| Pickerel Frog | Lithobates palustris | Not Listed | | |
| Pickerel Frog | Lithobates palustris | Not Listed | | |
| Pickering ivesia | Ivesia pickeringii | Species of Concern | Wherever found | |
| Pickering's morning-glory | Stylisma pickeringii | Species of Concern | Wherever found | |
| Pickle Springs amphipod | Stygobromus heteropodus | Resolved Taxon | Wherever found | |
| Piebald Madtom | Noturus gladiator | Under Review | Wherever found | |
| Pied-billed Grebe | Podilymbus podiceps | Species of Concern | Wherever found | |
| Piedmont Aster | Eurybia mirabilis | Species of Concern | Wherever found | |
| Piedmont barren strawberry | Waldsteinia lobata | Status Undefined | | |
| Piedmont Blue burrower | Cambarus harti | Status Undefined | Wherever found | |
| Piedmont Blue Burrower | Cambarus hartii | Not Listed | | |
| piedmont false pimpernel | Lindernia monticola | Resolved Taxon | Wherever found | |
| Piedmont meadow-rue | Thalictrum macrostylum | Species of Concern | Wherever found | |
| Piedmont ragwort | Packera millefolia | Species of Concern | Wherever found | |
| Pied tamarin | Saguinus bicolor | Endangered | Wherever found | 10-19-1976 |
| Pierpoint Springs liveforever | Dudleya cymosa costifolia | Species of Concern | Wherever found | |
| Pigeon Mountain salamander | Plethodon petraeus | Resolved Taxon | Wherever found | |
| Pigeon wings | Clitoria fragrans | Threatened | | 04-27-1993 |
| Pig-footed bandicoot | Chaeropus ecaudatus | Endangered | Wherever found | 12-02-1970 |
| Pikes Peak Spring parsley | Oreoxis humilis | Resolved Taxon | Wherever found | |
| Piko anobiid beetle | Holcobius pikoensis | Species of Concern | Wherever found | |
| Pileated woodpecker | dryocopus pileatus | Species of Concern | Wherever found | |
| Pillar Coral | Dendrogyra cylindrus | Threatened | Wherever found | 11-13-2014 |
| pilo | Kadua laxiflora | Endangered | Wherever found | 10-08-1992 |
| Pilo kea lau li`i | Melicope rostrata | Endangered | Wherever found | 05-13-2010 |
| Pilo kea long-horned beetle | Plagithmysus platydesmae | Species of Concern | Wherever found | |
| Pima pineapple cactus | Coryphantha scheeri var. robustispina | Endangered | Wherever found | 09-23-1993 |
| Pimpleback | Cyclonaias pustulosa | Not Listed | | |
| Pinacate cactus mouse | Peromyscus eremicus papagensis | Species of Concern | Wherever found | |
| Pinaleno monkey grasshopper | Eumorsea pinaleno | Species of Concern | Wherever found | |
| Pinaleno mountainsnail | Oreohelix grahamensis | Resolved Taxon | Wherever found | |
| Pinalenos fleabane | Erigeron heligraphicus | Species of Concern | Wherever found | |
| Pinaleno talussnail | Sonorella grahamensis | Resolved Taxon | Wherever found | |
| Pine barren gentian | Gentiana autumnalis | Resolved Taxon | Wherever found | |
| Pine barrens boneset | Eupatorium resinosum | Species of Concern | Wherever found | |
| Pine barrens treefrog | Hyla andersonii | Original Data in Error - New Information Discovered | Florida | 12-18-1977 |
| Pine City stonecrop | Sedum pinetorum | Species of Concern | Wherever found | |
| Pinecone Holospira | Holospira pityis | Resolved Taxon | Wherever found | |
| Pine Hill ceanothus | Ceanothus roderickii | Endangered | Wherever found | 10-18-1996 |
| Pine Hill flannelbush | Fremontodendron californicum ssp. decumbens | Endangered | Wherever found | 10-18-1996 |
| Pine Island rice rat | Oryzomys palustris planirostris | Not Listed | Wherever found | |
| Pineland hoary-pea | Tephrosia mohrii | Species of Concern | Wherever found | |
| Pineland jacquemontia | Jacquemontia curtissii | Species of Concern | Wherever found | |
| Pineland plantain | Plantago sparsiflora | Species of Concern | Wherever found | |
| Pineland sandmat | Chamaesyce deltoidea pinetorum | Threatened | | 10-06-2017 |
| Pine Nut Mountains ivesia | Ivesia pityocharis | Species of Concern | Wherever found | |
| Pine Siskin | Carduelis pinus | Species of Concern | Wherever found | |
| Pinewoods darter | Etheostoma mariae | Resolved Taxon | Wherever found | |
| pinewoods shiner | Lythrurus matutinus | Species of Concern | Wherever found | |
| Pink fairy armadillo | Chlamyphorus truncatus | Endangered | Wherever found | 06-02-1970 |
| Pink-footed Shearwater | Ardenna creatopus | Species of Concern | Wherever found | |
| Pink-headed duck | Rhodonessa caryophyllacea | Endangered | Wherever found | 06-14-1976 |
| Pink Heelsplitter | Potamilus alatus | Not Listed | | |
| Pink mucket (pearlymussel) | Lampsilis abrupta | Endangered | Wherever found | 06-14-1976 |
| Pink Papershell | Potamilus ohiensis | Not Listed | | |
| Pink pigeon | Columba mayeri | Endangered | Wherever found | 01-12-1995 |
| Pink Salmon | Oncorhynchus gorbuscha | Not Listed | | |
| Pink sand-verbena | Abronia umbellata breviflora | Species of Concern | Wherever found | |
| Pink-shell azalea | Rhododendron vaseyi | Resolved Taxon | Wherever found | |
| Pinnacles buckwheat | Eriogonum nortonii | Resolved Taxon | Wherever found | |
| Pinnacles optioservus riffle beetle | Optioservus canus | Species of Concern | Wherever found | |
| Pinnacles shield-back katydid | Idiostatus kathleenae | Species of Concern | Wherever found | |
| pinnately-lobed brown-eyed susan | Rudbeckia triloba var. pinnatiloba | Species of Concern | Wherever found | |
| Pinnate spring-parsley | Cymopterus beckii | Resolved Taxon | Wherever found | |
| Pinninerve peperomia | Peperomia macraeana | Resolved Taxon | Wherever found | |
| Pinon | Tillandsia lineatispica | Species of Concern | Wherever found | |
| Pinon espinoso or cockspur | Erythrina eggersii | Species of Concern | Wherever found | |
| Pinos Altos fameflower | Talinum humile | Species of Concern | Wherever found | |
| Pinos Altos Mountainsnail | Oreohelix confragosa | Resolved Taxon | Wherever found | |
| Pinyon Jay | Gymnorhinus cyanocephalus | Under Review | Wherever found | |
| Piper's bluegrass | Poa piperi | Resolved Taxon | Wherever found | |
| Piping Plover | Charadrius melodus | Endangered | [Great Lakes watershed DPS] - Great Lakes, watershed in States of IL, IN, MI, MN, NY, OH, PA, and WI and Canada (Ont.) | 12-11-1985 |
| Piping Plover | Charadrius melodus | Threatened | [Atlantic Coast and Northern Great Plains populations] - Wherever found, except those areas where listed as endangered. | 12-11-1985 |
| Pipistrelles (Bats) | Pipistrellus sp. | Not Listed | | |
| Piratebush | Buckleya distichophylla | Species of Concern | Wherever found | |
| Pirate Perch | Aphredoderus sayanus | Not Listed | | |
| Pismo clarkia | Clarkia speciosa ssp. immaculata | Endangered | Wherever found | 12-15-1994 |
| Pistolgrip | Quadrula verrucosa | Not Listed | | |
| Pistol River pocket gopher | Thomomys umbrinus detumidus | Species of Concern | Wherever found | |
| Pitcher's thistle | Cirsium pitcheri | Threatened | Wherever found | 07-18-1988 |
| Pitkin Marsh lily | Lilium pardalinum ssp. pitkinense | Endangered | Wherever found | 10-22-1997 |
| Pitkin Marsh paintbrush | Castilleja uliginosa | Species of Concern | Wherever found | |
| Pit-Klamath Brook Lamprey | Entosphenus lethophagus | Not Listed | | |
| Pit roach | Lavinia symmetricus mitrulus | Species of Concern | Wherever found | |
| Pit Sculpin | Cottus perplexus | Not Listed | | |
| Pit Sculpin | Cottus pitensis | Not Listed | | |
| Pitted quillwort | Isoetes foveolata | Resolved Taxon | Wherever found | |
| Piute buckwheat | Eriogonum breedlovei breedlovei | Species of Concern | Wherever found | |
| Piute Mountains jewelflower | Streptanthus cordatus piutensis | Species of Concern | Wherever found | |
| Piute Mountains navarretia | Navarretia setiloba | Resolved Taxon | Wherever found | |
| Pizzini's amphipod | Stygobromus pizzinii | Species of Concern | Wherever found | |
| Plain Pocketbook | Lampsilis cardium | Not Listed | | |
| Plains bison | Bison bison bison | Under Review | Wherever found | |
| Plains gumweed | Grindelia oolepis | Resolved Taxon | Wherever found | |
| Plains Killifish | Fundulus zebrinus | Not Listed | | |
| Plains minnow | Hybognathus placitus | Species of Concern | Wherever found | |
| Plains Orangethroat Darter | Etheostoma spectabile | Not Listed | | |
| Plains Spadefoot | Spea bombifrons | Not Listed | | |
| Plains Spotted Skunk | Spilogale interrupta | Resolved Taxon | Wherever found | |
| Plains topminnow | Fundulus sciadicus | Resolved Taxon | Wherever found | |
| Plains wanderer (=collared-hemipode) | Pedionomus torquatus | Endangered | Wherever found | 06-04-1973 |
| Plank's catchfly | Silene plankii | Resolved Taxon | Wherever found | |
| Plaskett Meadows linanthus | Linanthus harknessii condensatus | Species of Concern | Wherever found | |
| Plateau catchfly | Silene petersonii | Species of Concern | Wherever found | |
| Plateau milkvine | Matelea edwardsensis | Resolved Taxon | Wherever found | |
| Plateau shiner | Cyprinella lepida | Resolved Taxon | Wherever found | |
| Plateau spot-tailed earless lizard | Holbrookia lacerata | Resolved Taxon | Wherever found | |
| Platte River caddisfly | Ironoquia plattensis | Resolved Taxon | Wherever found | |
| Pleasant Valley mariposa lily | Calochortus clavatus avius | Species of Concern | Wherever found | |
| Pleasant Valley tui chub | Siphateles bicolor ssp. | Species of Concern | Pleasant Valley | |
| Plicate rocksnail | Leptoxis plicata | Endangered | Wherever found | 10-28-1998 |
| Plumas ivesia | Ivesia sericoleuca | Species of Concern | Wherever found | |
| Plumas lupine | Lupinus onustus | Resolved Taxon | Wherever found | |
| Plumbeous Vireo | Vireo plumbeus | Species of Concern | | |
| Plumleaf azalea | Rhododendron prunifolium | Resolved Taxon | Wherever found | |
| Plummer's mariposa lily | Calochortus plummerae | Species of Concern | Wherever found | |
| Plymouth Redbelly Turtle = Plymouth Redbelly Cooter | Pseudemys rubriventris bangsi | Endangered | Wherever found | 04-02-1980 |
| Pocahontas cave amphipod | Stygobromus nanus | Species of Concern | Wherever found | |
| Pocketbook | Lampsilis ovata | Not Listed | | |
| Pocketed free-tailed bat | nyctinomops femorosaccus | Species of Concern | Wherever found | |
| Pocket-Pouch Fairy Shrimp | Branchinecta campestris | Not Listed | | |
| Podunk Groundsel | Packera malmstenii | Resolved Taxon | Wherever found | |
| Po`e | Portulaca sclerocarpa | Endangered | Wherever found | 03-04-1994 |
| Point Arena mountain beaver | Aplodontia rufa nigra | Endangered | Wherever found | 12-12-1991 |
| Point Conception jerusalem cricket | Ammopelmatus muwu | Species of Concern | Wherever found | |
| Point Lobos buckwheat | Eriogonum parvifolium lucidum | Resolved Taxon | Wherever found | |
| Point of Rocks tryonia | Tryonia elata | Resolved Taxon | Wherever found | |
| Point Reyes bentgrass | Agrostis clivicola punta-reyesensis | Resolved Taxon | Wherever found | |
| Point Reyes blue | Icaricia icariodes ssp. | Species of Concern | Wherever found | |
| Point Reyes horkelia | Horkelia marinensis | Species of Concern | Wherever found | |
| Point Reyes jumping mouse | Zapus trinotatus orarius | Species of Concern | Wherever found | |
| Point Reyes manzanita | Arctostaphylos uva-ursi marinensis | Resolved Taxon | Wherever found | |
| Point Reyes meadowfoam | Limnanthes douglasii sulphurea | Species of Concern | Wherever found | |
| Point Reyes mountain beaver | Aplodontia rufa phaea | Species of Concern | Wherever found | |
| Point Reyes paintbrush | Castilleja chrymactis | Resolved Taxon | Wherever found | |
| Point Reyes stickyseed | Blennosperma nanum robustum | Species of Concern | Wherever found | |
| Poison Canyon stickseed | Hackelia brevicula | Species of Concern | Wherever found | |
| 'Poko' noctuid moth | Agrotis crinigera | Resolved Taxon | Wherever found | |
| Polar bear | Ursus maritimus | Threatened | Wherever found | 05-15-2008 |
| Politus eopenthes click beetle | Eopenthes politus | Species of Concern | Wherever found | |
| Pollen's vanga | Xenopirostris polleni | Threatened | Wherever found | 01-12-1995 |
| Polynesian Starling | Aplonis tabuensis | Species of Concern | Wherever found | |
| Polynesian Storm Petrel | Nesofregetta fuliginosa | Species of Concern | Wherever found | |
| Pomarine Jaeger | Stercorarius pomarinus | Species of Concern | Wherever found | |
| Pomo bronze shoulderband | Helminthoglypta arrosa pomoensis | Species of Concern | Wherever found | |
| Ponape greater white-eye | Rukia longirostra | Endangered | Wherever found | 06-02-1970 |
| Ponape mountain starling | Aplonis pelzelni | Endangered | Wherever found | 06-02-1970 |
| Ponape short-eared owl | Asio flammeus ponapensis | Pre-Act Delisted Taxon | Wherever found | |
| Pondberry | Lindera melissifolia | Endangered | Wherever found | 07-31-1986 |
| Ponderosa Pine | Pinus ponderosa | Resolved Taxon | Wherever found | |
| Ponderous siltsnail | Cincinnatia ponderosa | Under Review | Wherever found | |
| Pondspice | Litsea aestivalis | Species of Concern | Wherever found | |
| Po`ola | Claoxylon sandwicense sandwicense | Resolved Taxon | Wherever found | |
| Po'olanui gall fly | Phaeogramma sp. | Resolved Taxon | Wherever found | |
| Po`ouli (honeycreeper) | Melamprosops phaeosoma | Extinction | Wherever found | 10-28-1975 |
| Popeye shiner | Notropis ariommus | Not Listed | Wherever found | |
| Poplar-leaved bidens | Bidens populifolia | Resolved Taxon | Wherever found | |
| Popolo | Cyanea solanacea | Endangered | Wherever found | 06-27-2013 |
| Popolo | Solanum nelsonii | Endangered | Wherever found | 10-31-2016 |
| Popolo ku mai | Solanum incompletum | Endangered | Wherever found | 11-10-1994 |
| Porsild's Starwort | Stellaria porsildii | Resolved Taxon | Wherever found | |
| Portal Talussnail | Sonorella neglecta | Resolved Taxon | Wherever found | |
| Porter sagebrush | Artemisia porteri | Resolved Taxon | Wherever found | |
| Porter's Feathergrass | Ptilagrostis porteri | Resolved Taxon | Wherever found | |
| Porter's goldenrod | Solidago porteri | Species of Concern | Wherever found | |
| Porter's groundsel | Packera porteri | Resolved Taxon | Wherever found | |
| Porter's, Key spurge | Chamaesyce porteriana keyensis | Species of Concern | Wherever found | |
| Porter's reedgrass | Calamagrostis porteri | Resolved Taxon | Wherever found | |
| Porter's, spurge | Chamaesyce porteriana scoparia | Species of Concern | Wherever found | |
| Potem Creek pebblesnail | Fluminicola potemicus | Resolved Taxon | Wherever found | |
| Potholes meadow vole | Microtus pennsylvanicus kincaidi | Species of Concern | Wherever found | |
| Potomac groundwater amphipod | Stygobromus tenuis potomacus | Resolved Taxon | Wherever found | |
| Potophila agrotis noctuid moth | Agrotis potophila | Species of Concern | Wherever found | |
| Poweshiek skipperling | Oarisma poweshiek | Endangered | Wherever found | 11-24-2014 |
| Prairie bush-clover | Lespedeza leptostachya | Threatened | Wherever found | 01-09-1987 |
| prairie chub | Macrhybopsis australis | Under Review | Wherever found | |
| Prairie Falcon | Falco mexicanus | Species of Concern | Wherever found | |
| Prairie gray fox | Urocyon cinereoargenteus ssp. ocythous | Under Review | Wherever found | |
| Prairie Loggerhead Shrike | Lanius ludovicianus excubitorides | Species of Concern | Wherever found | |
| Prairie mole cricket | Gryllotalpa major | Species of Concern | Wherever found | |
| Prairie moonwort | Botrychium gallicomontanum | Species of Concern | Wherever found | 06-09-1993 |
| Prairie Warbler | Setophaga discolor | Species of Concern | Wherever found | |
| Preble's meadow jumping mouse | Zapus hudsonius preblei | Threatened | wherever found | 05-13-1998 |
| Preble's shrew | Sorex preblei | Species of Concern | Wherever found | |
| Precious underwing | Catocala pretiosa pretiosa | Species of Concern | Wherever found | |
| Presidio clarkia | Clarkia franciscana | Endangered | Wherever found | 02-03-1995 |
| Presidio County springsnail | Fontelicella metcalfi | Species of Concern | Wherever found | |
| Presidio Manzanita | Arctostaphylos hookeri var. ravenii | Endangered | Wherever found | 11-29-1979 |
| Presidio mole | Scalopus aquaticus texanus | Species of Concern | Wherever found | |
| Preston Peak rock-cress | Arabis macdonaldiana | Species of Concern | Wherever found | |
| Preston White River springfish | Crenichthys baileyi albivallis | Resolved Taxon | Wherever found | |
| Preuss' red colobus monkey | Procolobus (=Colobus) preussi (=badius p.) | Endangered | Wherever found | 01-23-1984 |
| Pribilof Islands shrew | Sorex hydrodromus | Species of Concern | Wherever found | |
| Price''s potato-bean | Apios priceana | Threatened | | 01-05-1990 |
| Pricklypear islandsnail | Micrarionta opuntia | Species of Concern | Wherever found | |
| Prickly Sculpin | Cottus asper | Not Listed | | |
| Prieto tortugo | Ravenia urbanii | Resolved Taxon | Wherever found | |
| Prince of Wales flying squirrel | Glaucomys sabrinus griseifrons | Resolved Taxon | Wherever found | |
| Princess elimia | Elimia bellacrenata | Under Review | Wherever found | |
| Pringle hawkweed | Hieracium pringlei | Species of Concern | Wherever found | |
| Pringle lip fern | Cheilanthes pringlei insulare | Resolved Taxon | Wherever found | |
| Pringle monardella | Monardella pringlei | Species of Concern | Wherever found | |
| Priolan oliarus planthopper | Oliarus priola | Species of Concern | Wherever found | |
| Pristine crayfish | Cambarus pristinus | Resolved Taxon | Wherever found | |
| Proboscis monkey | Nasalis larvatus | Endangered | Wherever found | 06-14-1976 |
| Procellaris agrotis noctuid moth | Agrotis procellaris | Resolved Taxon | Wherever found | |
| Pronghorn | Antilocapra americana | Not Listed | | |
| Proserpina cave pseudoscorpion | Kleptochthonius proserpinae | Species of Concern | Wherever found | |
| Proserpine shiner | Cyprinella proserpina | Species of Concern | Wherever found | |
| Prospect Valley pocket gopher | Thomomys umbrinus muralis | Species of Concern | Wherever found | |
| Prostrate buckwheat | Eriogonum prociduum | Species of Concern | Wherever found | |
| Prostrate hosackia | Lotus nuttallianus | Species of Concern | Wherever found | |
| Prostrate milkweed | Asclepias prostrata | Endangered | | 03-30-2023 |
| prostrate pincushionplant | Navarretia prostrata | Species of Concern | Wherever found | |
| Prostrate spineflower | chorizanthe procumbens | Species of Concern | Wherever found | |
| Prothonotary Warbler | Protonotaria citrea | Species of Concern | Wherever found | |
| Provost's ochrotrichian micro caddisfly | Ochrotrichia provosti | Species of Concern | Wherever found | |
| Prune elimia | Elimia chiltonensis | Status Undefined | Wherever found | |
| Pryor Mountains Bladderpod | Lesquerella lesicii | Resolved Taxon | Wherever found | |
| Przewalski's horse | Equus przewalskii | Endangered | Wherever found | 06-14-1976 |
| Psammobian yellow-faced bee | Hylaeus psammobia | Resolved Taxon | Wherever found | |
| Pseudoscorpion | Kleptochthonius magnus | Status Undefined | Wherever found | |
| Pseudoscorpion | Kleptochthonius tantalus | Status Undefined | Wherever found | |
| (Pterostichus johnsoni) ground beetle | pterostichus johnsoni | Species of Concern | Wherever found | |
| Pua `ala | Brighamia rockii | Endangered | Wherever found | 10-08-1992 |
| Pua-hekili | Lysimachia hillebrandii | Resolved Taxon | Wherever found | |
| Puaiohi | Myadestes palmeri | Endangered | Wherever found | 03-11-1967 |
| Puakauhi | Canavalia hawaiiensis | Resolved Taxon | Wherever found | |
| Pualoalo | Hibiscus kokio | Species of Concern | Wherever found | |
| Pua pilo | Capparis sandwichiana | Species of Concern | Wherever found | |
| Pudu | Pudu pudu | Endangered | Wherever found | 06-14-1976 |
| Puerto Rican boa | Chilabothrus inornatus | Endangered | Wherever found | 10-13-1970 |
| Puerto Rican broad-winged hawk | Buteo platypterus brunnescens | Endangered | Wherever found | 09-09-1994 |
| Puerto Rican crested toad | Peltophryne lemur | Threatened | Wherever found | 08-04-1987 |
| Puerto Rican harlequin butterfly | Atlantea tulita | Threatened | Wherever found | 01-03-2023 |
| Puerto Rican nightjar | Antrostomus noctitherus | Endangered | Wherever found | 06-04-1973 |
| Puerto Rican Oriole | Icterus portoricensis | Species of Concern | Wherever found | |
| Puerto Rican parrot | Amazona vittata | Endangered | Wherever found | 03-11-1967 |
| Puerto Rican plain Pigeon | Patagioenas inornata wetmorei | Endangered | Wherever found | 10-13-1970 |
| Puerto Rican pygmy anole | Anolis occultus | Species of Concern | Wherever found | |
| Puerto Rican Screech-Owl | Megascops nudipes newtoni | Species of Concern | | |
| Puerto Rican sharp-shinned hawk | Accipiter striatus venator | Endangered | Wherever found | 09-09-1994 |
| Puerto Rican Skink | Spondylurus nitidus | Proposed Endangered | Wherever found | |
| Puerto Rican Vireo | Vireo latimeri | Species of Concern | Wherever found | |
| Puget oregonian | Cryptomastix devia | Resolved Taxon | Wherever found | |
| Pugnose minnow | Opsopoeodus emiliae | Status Undefined | Wherever found | |
| Pugnose Shiner | Notropis anogenus | Not Listed | | |
| Pulchrus thread bug | Empicoris pulchrus | Species of Concern | Wherever found | |
| Puma (=mountain lion) | Puma (=Felis) concolor (all subsp. except coryi) | Similarity of Appearance (Threatened) | U.S.A. (FL) | 08-14-1991 |
| Puna deinomimesan sphecid wasp | Deinomimesa punae | Species of Concern | Wherever found | |
| Pungent dwarf greasebush | Glossopetalon pungens var. pungens | Not Listed | | |
| Pungo white-footed mouse | Peromyscus leucopus easti | Resolved Taxon | Wherever found | |
| Pupa elimia | Elimia pupaeformis | Resolved Taxon | Wherever found | |
| Purgatory cave shrimp | Palaemonetes holthuisi | Resolved Taxon | Wherever found | |
| Puritan tiger beetle | Ellipsoptera puritana | Threatened | Wherever found | 08-07-1990 |
| Purple amole | Chlorogalum purpureum | Threatened | Wherever found | 03-20-2000 |
| Purple bankclimber (mussel) | Elliptoideus sloatianus | Threatened | Wherever found | 03-16-1998 |
| Purple bean | Villosa perpurpurea | Endangered | Wherever found | 01-10-1997 |
| Purple Cat's paw (=Purple Cat's paw pearlymussel) | Epioblasma obliquata | Endangered | Wherever found; Except where listed as Experimental Populations | 07-10-1990 |
| Purple Cat's paw (=Purple Cat's paw pearlymussel) | Epioblasma obliquata | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Purpledisk honeycombhead | Balduina atropurpurea | Resolved Taxon | Wherever found | |
| Purple-faced langur | Presbytis senex | Threatened | Wherever found | 10-19-1976 |
| Purple false-foxglove | Tomanthera skinneriana | Species of Concern | Wherever found | |
| Purple Finch | Carpodacus purpureus | Species of Concern | Wherever found | |
| Purple fringeless orchid | Platanthera peramoena | Resolved Taxon | Wherever found | |
| Purple gay-mallow | Batesimalva violacea | Resolved Taxon | Wherever found | |
| purple lilliput | Toxolasma lividum | Resolved Taxon | Wherever found | 09-29-2020 |
| Purple martin | progne subis | Species of Concern | Wherever found | |
| Purple monkey-flower | Mimulus purpureus purpureus | Species of Concern | Wherever found | |
| Purple mountain parsley | Oreonana purpurascens | Resolved Taxon | Wherever found | |
| Purple Sandpiper | Calidris maritima | Species of Concern | Wherever found | |
| Purple skimmer | Libellula jesseana | Under Review | Wherever found | |
| Purple-spined Hedgehog cactus | Echinocereus engelmannii var. purpureus | Original Data in Error - Taxonomic Revision | | 10-11-1979 |
| Purple Swamphen | Porphyrio porphyrio | Species of Concern | Wherever found | |
| Purple, Texas spike | Hexalectris warnockii | Species of Concern | Wherever found | |
| Purple Wartyback | Cyclonaias tuberculata | Not Listed | | |
| Pussytoes ragwort | Packera antennariifolia | Resolved Taxon | Wherever found | |
| Putnam County Cave crayfish | Procambarus morrisi | Under Review | Wherever found | |
| Putnam minute moss beetle | Ochthebius putnamensis | Species of Concern | Wherever found | |
| Pu`uka`a | Cyperus trachysanthos | Endangered | Wherever found | 10-10-1996 |
| Puzzle elimia | Elimia varians | Species of Concern | Wherever found | |
| Pygmy chimpanzee | Pan paniscus | Endangered | Wherever found | 10-19-1976 |
| Pygmy elimia | Elimia pygmaea | Resolved Taxon | Wherever found | |
| Pygmy fringe-tree | Chionanthus pygmaeus | Endangered | | 01-21-1987 |
| Pygmy hog | Sus salvanius | Endangered | Wherever found | 06-02-1970 |
| Pygmy madtom | Noturus stanauli | Endangered | Wherever found | 04-27-1993 |
| Pygmy madtom | Noturus stanauli | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.84(t)(1)(i)) | 10-15-2007 |
| Pygmy Mountainsnail | Oreohelix pygmaea | Resolved Taxon | Wherever found | |
| Pygmy pebblesnail | Somatogyrus pygmaeus | Species of Concern | Wherever found | |
| Pygmypipes | Monotropsis odorata | Species of Concern | Wherever found | |
| Pygmy quillwort | Isoetes bolanderi pygmaea | Resolved Taxon | Wherever found | |
| Pygmy Rabbit | Brachylagus idahoensis | Endangered | Columbia Basin DPS (WA-Douglas, Grant, Lincoln, Adams, Benton Counties) | 11-30-2001 |
| Pygmy Rabbit | Brachylagus idahoensis | Under Review | Wherever found | |
| Pygmy rock-cress | Arabis pygmaea | Resolved Taxon | Wherever found | |
| Pygmy salamander | Desmognathus wrighti | Species of Concern | Wherever found | |
| Pygmy Sculpin | Cottus paulus (=pygmaeus) | Threatened | Wherever found | 09-28-1989 |
| Pygmy siltsnail | Cincinnatia parva | Under Review | Wherever found | |
| Pygmy siltsnail | Floridobia parva | Under Review | Wherever found | |
| Pygmy Talussnail | Sonorella micra | Resolved Taxon | Wherever found | |
| Pygmy Three-toed Sloth | Bradypus pygmaeus | Proposed Threatened | Wherever found | |
| Pygmy whitefish | prosopium coulterii | Species of Concern | Wherever found | |
| Pymatuning red-backed vole | Clethrionomys gapperi paludicola | Resolved Taxon | Wherever found | |
| pyramid pigtoe | Pleurobema rubrum | Resolved Taxon | Wherever found | |
| Pyramid slitshell | Gyrotoma pyramidata | Resolved Taxon | Wherever found | |
| Pyrenean ibex | Capra pyrenaica pyrenaica | Endangered | Wherever found | 06-02-1970 |
| Pyrrhuloxia | Cardinalis sinuatus | Species of Concern | | |
| Quadrate pebblesnail | Somatogyrus quadratus | Species of Concern | Wherever found | |
| Quartzite Hill Talussnail | Sonorella bowiensis | Resolved Taxon | Wherever found | |
| quayle's ragwort | senecio quaylei | Resolved Taxon | Wherever found | |
| Queen Alexandra's birdwing butterfly | Troides alexandrae | Endangered | Wherever found | 09-21-1989 |
| Queen Charlotte goshawk | Accipiter gentilis laingi | Resolved Taxon | Wherever found | |
| Queen Charlotte goshawk | Accipiter gentilis laingi | Threatened | British Columbia, Canada | 08-31-2012 |
| Queen Conch | Aliger gigas | Threatened | | |
| Queen-of-the-forest | Filipendula occidentalis | Species of Concern | Wherever found | |
| Queensland hairy-nosed wombat (incl. Barnard's) | Lasiorhinus krefftii (formerly L. barnardi and L. gillespiei) | Endangered | Wherever found | 12-02-1970 |
| Queensland rat-kangaroo | Bettongia tropica | Endangered | Wherever found | 12-02-1970 |
| Queen snake | Regina septemvittata | Species of Concern | Wherever found | |
| Quina | Antirhea portoricensis | Resolved Taxon | Wherever found | |
| Quincy lupine | Lupinus dalesiae | Resolved Taxon | Wherever found | |
| Quino checkerspot butterfly | Euphydryas editha quino (=E. e. wrighti) | Endangered | Wherever found | 01-16-1997 |
| Quitobaquito tryonia | Tryonia quitobaquitae | Proposed Endangered | Wherever found | |
| Quokka | Setonix brachyurus | Endangered | Wherever found | 06-04-1973 |
| Rabbit bandicoot | Macrotis lagotis | Endangered | Wherever found | 12-02-1970 |
| Rabbitsfoot | Quadrula cylindrica cylindrica | Threatened | Wherever found | 10-17-2013 |
| Radak Micronesian pigeon | Ducula oceanica ratakensis | Status Undefined | Wherever found | |
| Radford's sedge | Carex radfordii | Species of Concern | Wherever found | |
| Radford's St. John's Wort | Hypericum radfordiorum | Species of Concern | | |
| Radford's St. John's Wort | Hypericum sp. 1 | Resolved Taxon | Wherever found | |
| Radulan odynerus vespid wasp | Odynerus radula | Species of Concern | Wherever found | |
| Rafinesque's big-eared bat | Plecotus rafinesquii | Species of Concern | Wherever found | |
| Raiches manzanita | Arctostaphylos stanfordiana raichei | Species of Concern | Wherever found | |
| Railroad Valley skipper | Hesperia uncas fulvapalla | Resolved Taxon | Wherever found | |
| Railroad Valley Skipper | Hesperia uncas reeseorum | Resolved Taxon | Wherever found | |
| Railroad Valley springfish | Crenichthys nevadae | Threatened | Wherever found | 03-31-1986 |
| Railroad Valley toad | Anaxyrus nevadensis | Under Review | | |
| Railroad Valley tui chub | Siphateles bicolor ssp. 7 | Resolved Taxon | Railroad Valley | |
| Rainbow | Cambarunio iris | Not Listed | | |
| Rainbow manzanita | arctostaphylos rainbowensis | Species of Concern | Wherever found | |
| Rainbow smelt | Osmerus mordax | Species of Concern | Wherever found | |
| Rameshwaram Parachute Spider | Poecilotheria hanumavilasumica | Under Review | Wherever found | |
| Ramona cinquuefoil | Horkelia truncata | Resolved Taxon | Wherever found | |
| Ramona grasshopper mouse | Onychomys torridus | Not Listed | | |
| Ramona spineflower | Chorizanthe leptotheca | Species of Concern | Wherever found | |
| Rampart Talussnail | Sonorella reederi | Resolved Taxon | Wherever found | |
| Ramsey Canyon leopard frog | Rana subaquavocalis | Resolved Taxon | Wherever found | |
| Ramshaw Meadows sand-verbena | Abronia alpina | Resolved Taxon | Wherever found | |
| Ram's-head lady's-slipper | Cypripedium arietinum | Resolved Taxon | Wherever found | |
| Rapids Clubtail Dragonfly | Gomphus quadricolor | Not Listed | | |
| Rare skipper | Problema bulenta | Not Listed | Wherever found | |
| Raso lark | Alauda razae | Endangered | Wherever found | 01-12-1995 |
| Rattlesnake-master borer moth | Papaipema eryngii | Resolved Taxon | Wherever found | |
| Ravendale skullcap | Scutellaria nana | Resolved Taxon | Wherever found | |
| Raven's milk-vetch | Astragalus monoensis ravenii | Species of Concern | Wherever found | |
| Raven's seedbox | Ludwigia ravenii | Under Review | Wherever found | |
| Ravine sedge | Carex impressinervia | Under Review | Wherever found | |
| Rawhide Hill onion | Allium tuolumnense | Resolved Taxon | Wherever found | |
| Rawson's flaming trumpet | Collomia rawsoniana | Resolved Taxon | Wherever found | |
| Rayed Bean | Villosa fabalis | Endangered | Wherever found | 03-15-2012 |
| Rayed creekshell | Anodontoides radiatus | Not Listed | Wherever found | |
| Rayless layia | Layia discoidea | Species of Concern | Wherever found | |
| Raynor's huckleberry | Vaccinium crassifolium | Species of Concern | Wherever found | |
| Razorback sucker | Xyrauchen texanus | Endangered | Wherever found | 10-23-1991 |
| Razorbill | Alca torda | Species of Concern | Wherever found | |
| Razor-billed curassow | Mitu mitu mitu | Endangered | Wherever found | 06-14-1976 |
| Reakirt's blue butterfly | Echinargus isola | Resolved Taxon | Wherever found | |
| Reclining bulrush | Scirpus flaccidifolius | Species of Concern | Wherever found | |
| Recurved larkspur | calochortus pulchellus | Species of Concern | Wherever found | |
| Recurved larkspur | Delphinium recurvatum | Species of Concern | Wherever found | |
| Redacted cave amphipod | Stygobromus redactus | Species of Concern | Wherever found | |
| Red anomis noctuid moth | Anomis vulpicolor | Species of Concern | Wherever found | |
| Red-backed squirrel monkey | Saimiri oerstedii | Endangered | Wherever found | 06-02-1970 |
| Red-bellied monkey | Cercopithecus erythrogaster | Endangered | Wherever found | 10-19-1976 |
| Red-billed curassow | Crax blumenbachii | Endangered | Wherever found | 12-02-1970 |
| Red-billed Pigeon | Patagioenas flavirostris | Species of Concern | Wherever found | |
| Red-billed Tropicbird | Phaethon aethereus mesonauta | Species of Concern | | |
| Red Bluff rush | Juncus leiospermus leiospermus | Resolved Taxon | Wherever found | |
| Red-breasted Merganser | Mergus serrator | Species of Concern | | |
| red-breasted sapsucker | Sphyrapicus ruber | Status Undefined | Wherever found | |
| Redbreast Sunfish | Lepomis auritus | Not Listed | | |
| Red-browed parrot | Amazona rhodocorytha | Endangered | Wherever found | 06-02-1970 |
| Red Canyon beardtongue | Penstemon bracteatus | Species of Concern | Wherever found | |
| Red Canyon catchfly | Silene petersonii minor | Resolved Taxon | Wherever found | |
| Red Canyon phlox | Phlox gladiformis | Resolved Taxon | Wherever found | |
| Red-capped parrot | Pionopsitta pileata | Endangered | Wherever found | 06-14-1976 |
| Red coachwhip | masticophis flagellum ssp. piceus | Species of Concern | Wherever found | |
| Red-cockaded woodpecker | Dryobates borealis | Threatened | Wherever found | 10-13-1970 |
| Red crossbill | Loxia curvirostra | Species of Concern | Wherever found | |
| Red-crowned parrot | Amazona viridigenalis | Resolved Taxon | Wherever found | |
| Reddish Egret | Egretta rufescens | Species of Concern | Wherever found | |
| Red Drum | Sciaenops ocellatus | Not Listed | | |
| Red-eared nose-spotted monkey | Cercopithecus erythrotis | Endangered | Wherever found | 10-19-1976 |
| Red-Eared Slider | Trachemys scripta elegans | Not Listed | | |
| Redear Sunfish | Lepomis microlophus | Not Listed | | |
| Redell's cave amphipod | Stygobromus reddelli | Resolved Taxon | Wherever found | |
| Redeye Bass | Micropterus coosae | Not Listed | | |
| Red-faced Cormorant | Urile urile | Species of Concern | Wherever found | |
| Red-faced malkoha (cuckoo) | Phaenicophaeus pyrrhocephalus | Endangered | Wherever found | 06-02-1970 |
| Red-faced Warbler | Cardellina rubrifrons | Species of Concern | Wherever found | |
| Redfin Darter | Etheostoma whipplei | Not Listed | | |
| Red fir catchfly | Silene invisa | Resolved Taxon | Wherever found | |
| Red-flowered lotus | Lotus rubriflorus | Species of Concern | Wherever found | |
| Red-footed Booby | Sula sula | Species of Concern | Wherever found | |
| Red-footed Booby | Sula sula sula | Species of Concern | | |
| Red-fruited desert-parsley | Lomatium erythrocarpum | Species of Concern | Wherever found | |
| Redheaded sphecid wasp | Eucerceris ruficeps | Species of Concern | Wherever found | |
| Red-headed Woodpecker | Melanerpes erythrocephalus | Species of Concern | Wherever found | |
| Red Hills butterweed | Senecio clevelandii heterophyllus | Resolved Taxon | Wherever found | |
| Red Hills roach | Lavinia symmetricus ssp. | Species of Concern | Wherever found | |
| Red Hills salamander | Phaeognathus hubrichti | Threatened | Wherever found | 01-03-1977 |
| Red Hills soaproot | Chlorogalum grandiflorum | Species of Concern | Wherever found | |
| Red Hills unique whirligig | Spanglerogyrus albiventris | Species of Concern | Wherever found | |
| Red Hills vervain | Verbena californica | Threatened | Wherever found | 10-14-1998 |
| Red kangaroo | Macropus rufus | Recovery | Wherever found | 12-30-1974 |
| Red Knot | Calidris canutus roselaari | Resolved Taxon | Wherever found | |
| Red lechwe | Kobus leche | Threatened | Wherever found | 06-02-1970 |
| Red-legged Kittiwake | Rissa brevirostris | Species of Concern | Wherever found | |
| Redline Darter | Nothonotus rufilineatus | Not Listed | | |
| redlips darter | Etheostoma maydeni | Resolved Taxon | | |
| Red Mountain buckwheat | Eriogonum kelloggii | Resolved Taxon | Wherever found | |
| Red Mountain catchfly | Silene campanulata campanulata | Resolved Taxon | Wherever found | |
| Red Mountain stonecrop | Sedum eastwoodiae | Resolved Taxon | Wherever found | |
| Red-necked parrot | Amazona arausiaca | Endangered | Wherever found | 07-27-1979 |
| Red-necked Phalarope | Phalaropus lobatus | Species of Concern | Wherever found | |
| Red Parachute Spider | Poecilotheria miranda | Under Review | Wherever found | |
| Red Phalarope | Phalaropus fulicarius | Species of Concern | Wherever found | |
| Red River Pupfish | Cyprinodon rubrofluviatilis | Not Listed | | |
| Red Rock Canyon aster | ionactis caelestis | Species of Concern | Wherever found | |
| Redrock stonefly | Anacroneuria wipukupa | Under Review | Wherever found | |
| Red Rock tarweed | Hemizonia arida | Species of Concern | Wherever found | |
| Red-root yampah | Perideridia erythrorhiza | Species of Concern | Wherever found | |
| Red Shiner | Cyprinella lutrensis | Not Listed | | |
| Red-shouldered hawk | buteo lineatus | Species of Concern | Wherever found | |
| Redside Dace | Clinostomus elongatus | Not Listed | | |
| Redside Shiner | Richardsonius balteatus | Not Listed | | |
| Red siskin | Carduelis cucullata | Endangered | Wherever found | 06-14-1976 |
| Redslate Ornamental Tarantula | Poecilotheria rufilata | Under Review | Wherever found | |
| Red-spectacled parrot | Amazona pretrei pretrei | Endangered | Wherever found | 06-14-1976 |
| Redspot Chub | Nocomis asper | Not Listed | | |
| Redspotted Sunfish | Lepomis miniatus | Not Listed | | |
| Red Swamp Crayfish | Procambarus clarkii | Not Listed | | |
| Red-tailed Hawk | Buteo jamaicensis | Not Listed | | |
| Red-tailed parrot | Amazona brasiliensis | Endangered | Wherever found | 09-28-1990 |
| Red-tailed Tropicbird | Phaethon rubricauda | Species of Concern | | |
| Red-tailed Tropicbird | Phaethon rubricauda melanorhynchos | Species of Concern | | |
| Redtail sphecid wasp | Ectemnius rubrocaudatus | Species of Concern | Wherever found | |
| Red-throated Loon | Gavia stellata | Species of Concern | Wherever found | |
| red tree vole | Arborimus longicaudus | Resolved Taxon | North Oregon Coast population | |
| Redveined prairie leafhopper | Aflexia rubranura | Species of Concern | Wherever found | |
| Red wolf | Canis rufus | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Red wolf | Canis rufus | Experimental Population, Non-Essential | U.S.A. (portions of NC and TN see 17.84(c)(9)) | 11-19-1986 |
| Redwood shoulderband | Helminthoglypta sequoicola consors | Species of Concern | Wherever found | |
| Reed's Mountain woodlandsnail | Ashmunella ferrissi | Resolved Taxon | Wherever found | |
| Refton Cave planarian | Sphalloplana pricei | Species of Concern | Wherever found | |
| Refugio manzanita | Arctostaphylos refugioensis | Species of Concern | Wherever found | |
| Regal Burrowing crayfish | Procambarus regalis | Status Undefined | Wherever found | |
| Regal fritillary | Speyeria idalia | Resolved Taxon | Wherever found | |
| Reid's stonecrop | Sedum moranii | Species of Concern | Wherever found | |
| Reisen's hydropsyche caddisfly | Hydropsyche reiseni | Species of Concern | Wherever found | |
| Relict dace | Relictus solitarius | Under Review | Wherever found | |
| Relict darter | Etheostoma chienense | Threatened | Wherever found | 12-27-1993 |
| Relict gull | Larus relictus | Endangered | Wherever found | 06-14-1976 |
| Relict leopard Frog | Lithobates onca | Resolved Taxon | Wherever found | |
| Relict trillium | Trillium reliquum | Endangered | Wherever found | 04-04-1988 |
| Relictual slender salamander | Batrachoseps relictus | Proposed Endangered | Wherever found | |
| Remote conehead katydid | Conocephaloides remotus | Resolved Taxon | Wherever found | |
| Remy's `anaunau | Lepidium bidentatum remyi | Species of Concern | Wherever found | |
| Remy's nehe | Lipochaeta remyi | Resolved Taxon | Wherever found | |
| Repand Twinpod | Physaria repanda | Resolved Taxon | Wherever found | |
| Resplendent quetzel | Pharomachrus mocinno ssp. mocinno | Endangered | Wherever found | 06-14-1976 |
| Reticulate collared lizard | Crotaphytus reticulatus | Resolved Taxon | Wherever found | |
| Reticulated flatwoods salamander | Ambystoma bishopi | Endangered | Wherever found | 02-10-2009 |
| Reticulated gecko | Coleonyx reticulatus | Resolved Taxon | Wherever found | |
| Reunion cuckoo-shrike | Coquus newtoni | Endangered | Wherever found | 06-02-1970 |
| Reveal indian paintbrush | Castilleja revealii | Species of Concern | Wherever found | |
| Reveal's buckwheat | Eriogonum contiguum | Resolved Taxon | Wherever found | |
| Reverse pepplesnail | Somatogyrus alcoviensis | Under Review | Wherever found | |
| Ribbed elimia | Elimia laeta | Resolved Taxon | Wherever found | |
| Ribbed slitshell | Gyrotoma pumila | Resolved Taxon | Wherever found | |
| Richardson's ground squirrel | Spermophilus richardsoni nevadensis | Resolved Taxon | Wherever found | |
| Rich Mountain cave beetle | Pseudanophthalmus krekeleri | Species of Concern | Wherever found | |
| Rich Mountain salamander | Plethodon ouachitae | Resolved Taxon | Wherever found | |
| Rich Mt. slitmouth | Stenotrema pilsbryi | Species of Concern | Wherever found | |
| Ricksecker's water scavenger beetle | Hydrochara rickseckeri | Species of Concern | Wherever found | |
| Ricord's rock iguana | Cyclura ricordi | Resolved Taxon | | |
| Ridgeway's hawk | Buteo ridgwayi | Under Review | Wherever found | |
| Riffle beetle | Microcylloepus sp | Status Undefined | Wherever found | |
| rim rock crowned snake | Tantilla oolitica | Proposed Endangered | Wherever found | |
| Rincon ceanothus | Ceanothus confusus | Species of Concern | Wherever found | |
| Rincon Mountain Rockcress | Pennellia tricornuta | Resolved Taxon | Wherever found | |
| Rincon Talussnail | Sonorella bagnarai | Resolved Taxon | Wherever found | |
| Ring-billed Gull | Larus delawarensis | Species of Concern | Wherever found | |
| Ringed hornsnail | Pleurocera annulifera | Species of Concern | Wherever found | |
| Ringed map turtle | Graptemys oculifera | Threatened | Wherever found | 12-23-1986 |
| Ringed seal | Phoca (=Pusa) hispida ladogensis | Endangered | Ladoga subspecies | 02-26-2013 |
| Ringed Seal | Phoca (=Pusa) hispida botnica | Threatened | Wherever found | 02-26-2013 |
| Ringed Seal | Phoca (=Pusa) hispida hispida | Threatened | Wherever found | 02-26-2013 |
| Ringed Seal | Phoca (=Pusa) hispida ochotensis | Threatened | Okhotsk subspecies | 02-26-2013 |
| Ringneck snake | diadophis punctatus | Species of Concern | Wherever found | |
| Ring Pink | Obovaria retusa | Endangered | Wherever found | 09-29-1989 |
| Ring Pink | Obovaria retusa | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Ringtail | bassariscus astutus | Species of Concern | Wherever found | |
| Rio de Oro Dama gazelle | Gazella dama lozanoi | Endangered | Wherever found | 06-02-1970 |
| Rio Grande bluntnose shiner | Notropis simus simus | Resolved Taxon | Wherever found | |
| Rio Grande chub | Gila pandora | Resolved Taxon | Wherever found | |
| Rio Grande cooter | Pseudemys gorzugi | Resolved Taxon | Wherever found | |
| Rio Grande cutthroat trout | Oncorhynchus clarkii virginalis | Not Listed | Wherever found | |
| Rio Grande darter | Etheostoma grahami | Species of Concern | Wherever found | |
| Rio Grande lesser siren | Siren intermedia texana | Species of Concern | Wherever found | |
| Rio Grande shiner | Notropis jemezanus | Under Review | Wherever found | |
| Rio Grande Silvery Minnow | Hybognathus amarus | Endangered | Wherever found, except where listed as an experimental population | 07-20-1994 |
| Rio Grande Silvery Minnow | Hybognathus amarus | Experimental Population, Non-Essential | Rio Grande, from Little Box Canyon (approximately 10.4 river miles downstream of Fort Quitman, TX) to Amistad Dam; and on the Pecos River, from its confluence with Independence Creek to its confluence with the Rio Grande | 12-08-2008 |
| Rio Grande Sucker | Catostomus plebeius | Resolved Taxon | Wherever found | |
| Rio Grand Holospira | Holospira riograndensis | Under Review | Wherever found | |
| Riparian brush rabbit | Sylvilagus bachmani riparius | Endangered | Wherever found | 02-23-2000 |
| Riparian woodrat (=San Joaquin Valley) | Neotoma fuscipes riparia | Endangered | Wherever found | 02-23-2000 |
| Ripley milk-vetch | Astragalus ripleyi | Species of Concern | Wherever found | |
| Ripley's senna | Senna ripleyana | Resolved Taxon | Wherever found | |
| Ripley wild-buckwheat | Eriogonum ripleyi | Species of Concern | Wherever found | |
| Riverbank vervain | Verbena riparia | Species of Concern | Wherever found | |
| River Carpsucker | Carpiodes carpio | Not Listed | | |
| River Chub | Nocomis micropogon | Not Listed | | |
| River Darter | Percina shumardi | Not Listed | | |
| River Goby | Awaous banana | Not Listed | | |
| Riverine Clingfish | Gobiesox nudus | Not Listed | | |
| Riverine Clubtail | Stylurus amnicola | Not Listed | | |
| River lamprey | Lampetra ayresii | Resolved Taxon | Wherever found | |
| River otter | Lontra canadensis | Resolved Taxon | Wherever found | |
| River Redhorse | Moxostoma carinatum | Status Undefined | Wherever found | |
| River rock-daisy | Perityle warnockii | Resolved Taxon | Wherever found | |
| River Shiner | Notropis blennius | Not Listed | | |
| Riverside cuckoo bee | Holcopasites ruthae | Resolved Taxon | Wherever found | |
| Riverside fairy shrimp | Streptocephalus woottoni | Endangered | Wherever found | 08-03-1993 |
| River terrapin | Batagur baska | Endangered | Wherever found | 06-02-1970 |
| Roan Mountain bluet | Hedyotis purpurea var. montana | Endangered | Wherever found | 04-05-1990 |
| Roan Mountain false goats beard | Astilbe crenatiloba | Species of Concern | Wherever found | |
| Roanoke Bass | Ambloplites cavifrons | Not Listed | | |
| Roanoke logperch | Percina rex | Endangered | Wherever found | 08-18-1989 |
| Roanoke Slabshell | Elliptio roanokensis | Not Listed | | |
| Roan supercoil | Paravitrea varidens | Species of Concern | Wherever found | |
| Robber Baron Cave Meshweaver | Cicurina baronia | Endangered | Wherever found | 12-26-2000 |
| Robber fly | Proctacanthus species | Under Review | Wherever found | |
| Robbins' cinquefoil | Potentilla robbinsiana | Recovery | Wherever found | 09-17-1980 |
| Robbins, milk-vetch | Astragalus robbinsii alpiniformis | Resolved Taxon | Wherever found | |
| Robbins, milk-vetch | Astragalus robbinsii robbinsii | Resolved Taxon | Wherever found | |
| Robbins, western ssp. milk-vetch | Astragalus robbinsii occidentalis | Species of Concern | Wherever found | |
| Robert's alloperlan stonefly | Alloperla roberti | Resolved Taxon | Wherever found | |
| Robert's stonecrop | Sedum robertsianum | Species of Concern | Wherever found | |
| Robert's wingless thread bug | Nesidiolestes roberti | Species of Concern | Wherever found | |
| Robinson's pepper-grass | lepidium virginicum var. robinsonii | Species of Concern | Wherever found | |
| Robinson's rain scarab beetle | Phoebetus robinsoni | Resolved Taxon | Wherever found | |
| Robison's monardella | Monardella robisonii | Species of Concern | Wherever found | |
| Robust bidens | Bidens valida | Resolved Taxon | Wherever found | |
| Robust dubiraphian riffle beetle | Dubiraphia robusta | Species of Concern | Wherever found | |
| Robust Hoffmann's buckwheat | Eriogonum hoffmannii robustius | Resolved Taxon | Wherever found | |
| Robust Holospira | Holospira pasonis | Resolved Taxon | Wherever found | |
| Robust monardella | monardella villosa ssp. globosa | Species of Concern | Wherever found | |
| Robust Oak | Quercus robusta | Resolved Taxon | Wherever found | |
| Robust pentagenian burrowing mayfly | Pentagenia robusta | Resolved Taxon | Wherever found | |
| Robust prickly-poppy | Argemone munita robusta | Resolved Taxon | Wherever found | |
| Robust redhorse | Moxostoma robustum | Under Review | Wherever found | |
| Robust spineflower | Chorizanthe robusta var. robusta | Endangered | Wherever found | 02-04-1994 |
| Robust tryonia | Tryonia robusta | Species of Concern | Wherever found | |
| Rock Bass | Ambloplites rupestris | Not Listed | | |
| Rockcastle aster | Eurybia saxicastellii | Not Listed | | |
| Rock Creek broomrape | Orobanche valida valida | Species of Concern | Wherever found | |
| Rock darter | Etheostoma rupestre | Resolved Taxon | Wherever found | |
| Rock gnome lichen | Gymnoderma lineare | Endangered | Wherever found | 01-18-1995 |
| Rock lady | Holmgrenanthe petrophila | Species of Concern | Wherever found | |
| Rock monardella | Monardella viridis saxicola | Resolved Taxon | Wherever found | |
| Rock Pocketbook | Arcidens confragosus | Not Listed | | |
| Rock quillwort | Isoetes lithophila | Species of Concern | Wherever found | |
| Rock Sandpiper | Calidris ptilocnemis ptilocnemis | Species of Concern | Wherever found | |
| Rock sanicle | Sanicula saxatilis | Species of Concern | Wherever found | |
| Rock's nehe | Lipochaeta rockii | Resolved Taxon | Wherever found | |
| Rocky coast Pacific sideband | Monadenia fidelis pronotis | Resolved Taxon | Wherever found | |
| Rocky Mountain capshell | Acroloxus coloradensis | Resolved Taxon | Wherever found | |
| Rocky Mountain monkeyflower | Mimulus gemmiparus | Resolved Taxon | Wherever found | |
| Rocky Mountain Tailed Frog | Ascaphus montanus | Not Listed | | |
| Rocky shiner | Notropis suttkusi | Under Review | Wherever found | |
| Roderick's fritillary | Fritillaria grayana | Resolved Taxon | Wherever found | |
| Rodrigues fody | Foudia flavicans | Endangered | Wherever found | 01-12-1995 |
| Rodrigues fruit bat (=flying fox) | Pteropus rodricensis | Endangered | Wherever found | 01-23-1984 |
| Rodrigues warbler (old world warbler) | Bebrornis rodericanus | Endangered | Wherever found | 06-02-1970 |
| Rogers' cave beetle | Pseudanophthalmus rogersae | Species of Concern | Wherever found | |
| Rogue Creek hydroptila caddisfly | Hydroptila okaloosa | Resolved Taxon | Wherever found | |
| Rolling pebblesnail | Somatogyrus strengi | Species of Concern | Wherever found | |
| Roseate Spoonbill | Platalea ajaja | Species of Concern | Wherever found | |
| Roseate tern | Sterna dougallii dougallii | Endangered | U.S.A. (Atlantic Coast south to NC), Canada (Newf., N.S, Que.), Bermuda | 11-02-1987 |
| Roseate tern | Sterna dougallii dougallii | Threatened | Western Hemisphere and adjacent oceans, incl. U.S.A. (FL, PR, VI), where not listed as endangered | 11-02-1987 |
| Roseate Tern | Sterna dougallii | Species of Concern | | |
| Rose-breasted Grosbeak | Pheucticus ludovicianus | Species of Concern | | |
| Rose-flowered foxtail cactus | Escobaria vivipara rosea | Resolved Taxon | Wherever found | |
| Rosemary-mint | Poliomintha glabrescens | Resolved Taxon | Wherever found | |
| Rosemary wolf spider | Lycosa ericeticola | Resolved Taxon | Wherever found | |
| Rosemont talussnail | Sonorella rosemontensis | Resolved Taxon | Wherever found | |
| Rose-purple sand-verbena | Abronia umbellata acutalata | Species of Concern | Wherever found | |
| Rose-throated Becard | Pachyramphus aglaiae | Species of Concern | Wherever found | |
| Ross bentgrass | Agrostis rossiae | Resolved Taxon | Wherever found | |
| Ross micro-blind harvestman | Microcina sp | Resolved Taxon | Wherever found | |
| Ross's apatalestes tabanid fly | Apatalestes rossi | Resolved Taxon | Wherever found | |
| Ross's Gull | Rhodostethia rosea | Species of Concern | | |
| Ross' Woodfern | Dryopteris rossii | Resolved Taxon | Wherever found | |
| Roswell springsnail | Pyrgulopsis roswellensis | Endangered | Wherever found | 08-09-2005 |
| Rosy boa | Charina trivirgata | Species of Concern | Wherever found | |
| Rosy-pink spurge | Euphorbia rosescens | Status Undefined | Wherever found | |
| Rosyside Dace | Clinostomus funduloides | Not Listed | | |
| Rota blue damselfly | Ischnura luta | Endangered | Wherever found | 11-02-2015 |
| Rota bridled white-eye | Zosterops rotensis | Endangered | Wherever found | 01-22-2004 |
| Roth's blind ground beetle | Pterostichus rothi | Species of Concern | Wherever found | |
| Rothschild's starling (myna) | Leucopsar rothschildi | Endangered | Wherever found | 06-02-1970 |
| Roth's dune weevil | Trigonoscuta rothi algodones | Resolved Taxon | Wherever found | |
| Roth's dune weevil | Trigonoscuta rothi imperialis | Resolved Taxon | Wherever found | |
| Roth's dune weevil | Trigonoscuta rothi punctata | Resolved Taxon | Wherever found | |
| Roth's dune weevil | Trigonoscuta rothi rothi | Resolved Taxon | Wherever found | |
| Rotund rocksnail | Leptoxis ligata | Resolved Taxon | Wherever found | |
| Rotund Vertigo | Vertigo berryi | Resolved Taxon | Wherever found | |
| Rough Cactus Coral | Mycetophyllia ferox | Threatened | Wherever found | 11-13-2014 |
| Rough Fatmucket | Lampsilis straminea | Not Listed | | |
| Rough-headed oceanides seed bug | Oceanides rugosiceps | Species of Concern | Wherever found | |
| Roughhead shiner | Notropis semperasper | Under Review | Wherever found | |
| Rough hornsnail | Pleurocera foremani | Endangered | Wherever found | 12-02-2010 |
| Rough-leaved loosestrife | Lysimachia asperulaefolia | Endangered | Wherever found | 06-12-1987 |
| Rough-legged hawk | buteo lagopus | Species of Concern | Wherever found | |
| Rough-lined elimia | Elimia pilsbryi | Resolved Taxon | Wherever found | |
| Rough pigtoe | Pleurobema plenum | Endangered | Wherever found | 06-14-1976 |
| Rough pigtoe | Pleurobema plenum | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| rough popcornflower | Plagiobothrys hirtus | Endangered | Wherever found | 01-25-2000 |
| Rough rabbitsfoot | Quadrula cylindrica strigillata | Endangered | Wherever found | 01-10-1997 |
| Rough sculpin | Cottus asperrimus | Species of Concern | Wherever found | |
| Rough-seeded fameflower | Talinum rugospermum | Species of Concern | Wherever found | |
| Roughseed sea-purslane | Sesuvium trianthemoides | Species of Concern | Wherever found | |
| Rough-skinned newt | taricha granulosa | Species of Concern | Wherever found | |
| rough-stemmed aster | Symphyotrichum puniceum var. scabricaule | Not Listed | | |
| Round combshell | Epioblasma personata | Resolved Taxon | Wherever found | |
| Round Ebonyshell | Reginaia rotulata | Endangered | Wherever found | 10-10-2012 |
| Round hickorynut | Obovaria subrotunda | Threatened | Wherever found | 04-10-2023 |
| Round Island bolyeria boa | Bolyeria multocarinata | Endangered | Wherever found | 03-20-1980 |
| Round Island casarea boa | Casarea dussumieri | Endangered | Wherever found | 03-20-1980 |
| Round Island day gecko | Phelsuma guentheri | Endangered | Wherever found | 06-02-1970 |
| Round Island skink | Leiolopisma telfairi | Threatened | Wherever found | 06-22-1983 |
| Round leaf, Death Valley phacelia | Phacelia mustelina | Resolved Taxon | Wherever found | |
| Roundleaf four-o'clock | Mirabilis rotundifolia | Species of Concern | Wherever found | |
| Roundleaf Liverwort | Cephaloziella obtusilobula | Species of Concern | Wherever found | |
| Round-leaf willow | Salix ovalifolia glacialis | Resolved Taxon | Wherever found | |
| Round-leaved chaff-flower | Achyranthes splendens var. rotundata | Endangered | Wherever found | 03-26-1986 |
| Roundnose Minnow | Dionda episcopa | Not Listed | | |
| Round Pigtoe | Pleurobema sintoxia | Not Listed | | |
| Round-rib elimia | Elimia nassula | Under Review | Wherever found | |
| Round rocksnail | Leptoxis ampla | Threatened | Wherever found | 10-28-1998 |
| Round slitshell | Gyrotoma walkeri | Resolved Taxon | Wherever found | |
| Roundtail chub | Gila robusta | Not Listed | Wherever Found | |
| Roundtail chub | Gila robusta | Resolved Taxon | Lower Colorado River Basin DPS | |
| Round-tailed muskrat | Neofiber alleni | Species of Concern | Wherever found | |
| Round Whitefish | Prosopium cylindraceum | Not Listed | | |
| Royal catchfly | Silene regia | Resolved Taxon | Wherever found | |
| Royal cinclodes | Cinclodes aricomae | Endangered | Wherever found | 07-24-2012 |
| Royal, Florida palm | Roystonea elata | Resolved Taxon | Wherever found | |
| Royal Gorge stickleaf | Mentzelia densa | Resolved Taxon | Wherever found | |
| Royal marstonia (snail) | Marstonia ogmorhaphe | Endangered | Wherever found | 04-15-1994 |
| Royal Moth | sphingicampa blanchardi | Resolved Taxon | Wherever found | |
| royal penguin | Eudyptes schlegeli | Resolved Taxon | Wherever found | |
| Royal syarinid pseudoscorpion | Chitrella regina | Species of Concern | Wherever found | |
| Royal Tern | Thalasseus maximus | Species of Concern | Wherever found | |
| Roy Prairie pocket gopher | Thomomys mazama glacialis | Threatened | Wherever found | 05-09-2014 |
| Rubious Cave amphipod | Stygobromus lucifugus | Resolved Taxon | Wherever found | |
| Ruby bundleflower | Desmanthus bicornutus | Resolved Taxon | Wherever found | |
| Ruddy Duck | Oxyura jamaicensis | Species of Concern | | |
| Ruddy Duck | Oxyura jamaicensis jamaicensis | Species of Concern | Puerto Rico | |
| Ruddy Turnstone | Arenaria interpres morinella | Species of Concern | | |
| Rude's long-horned beetle | Necydalis rudei | Species of Concern | Wherever found | |
| rufa red knot | Calidris canutus rufa | Threatened | Wherever found | 01-12-2015 |
| Ruffed Grouse | Bonasa umbellus | Species of Concern | Wherever found | |
| Ruffo's Cave Amphipod | Paramexiweckelia ruffoi | Resolved Taxon | Wherever found | |
| Rufous-crowned Sparrow | Aimophila ruficeps | Species of Concern | Wherever found | |
| Rufous-crowned Sparrow | Aimophila ruficeps eremoeca | Species of Concern | | |
| Rufous Fantail | Rhipidura rufifrons mariae | Species of Concern | Wherever found | |
| Rufous Fantail | Rhipidura rufifrons saipanensis | Species of Concern | Wherever found | |
| Rufous Hummingbird | Selasphorus rufus | Species of Concern | Wherever found | |
| Rugel's pawpaw | Deeringothamnus rugelii | Endangered | | 09-26-1986 |
| Rugel''s Ragwort | Rugelia nudicaulis | Species of Concern | Wherever found | |
| Rugged hornsnail | Pleurocera alveare | Species of Concern | Wherever found | |
| Rugose rocksnail | Lithasia jayana | Species of Concern | Wherever found | |
| Rugulose yellow-faced bee | Nesoprosopis rugulosa | Resolved Taxon | Wherever found | |
| Ruidoso Snaggletooth | Gastrocopta ruidosensis | Resolved Taxon | Wherever found | |
| Rulien's miloderes weevil | Miloderes rulieni | Species of Concern | Wherever found | |
| Running buffalo clover | Trifolium stoloniferum | Recovery | | 06-05-1987 |
| Runyon huaco | Manfreda longiflora | Species of Concern | Wherever found | |
| Runyon's water-willow | Justicia runyonii | Species of Concern | Wherever found | |
| Rusby's desert-mallow | Sphaeralcea rusbyi eremicola | Species of Concern | Wherever found | |
| Rusby's fetid-marigold | Pectis rusbyi | Resolved Taxon | Wherever found | |
| Rusby's Thistle | Cirsium rusbyi | Resolved Taxon | Wherever found | |
| Rush Darter | Etheostoma phytophilum | Endangered | Wherever found | 09-08-2011 |
| Russian River tule perch | Hysterocarpus traskii pomo | Species of Concern | Wherever found | |
| Russian Sturgeon | Acipenser gueldenstaedtii | Proposed Endangered | Wherever found | |
| Rusty Blackbird | Euphagus carolinus | Species of Concern | Wherever found | |
| Rusty hedgehog cactus | Echinocereus russanthus | Resolved Taxon | Wherever found | |
| Rusty patched bumble bee | Bombus affinis | Endangered | Wherever found | 03-21-2017 |
| Rustyside sucker | Thoburnia hamiltoni | Resolved Taxon | Wherever found | |
| Ruth milkweed | Asclepias ruthiae | Resolved Taxon | Wherever found | |
| Ruth's golden aster | Pityopsis ruthii | Endangered | Wherever found | 07-18-1985 |
| Rydberg milk-vetch | Astragalus perianus | Original Data in Error - New Information Discovered | | 05-27-1978 |
| Rydberg parrya | Parrya rydbergii | Resolved Taxon | Wherever found | |
| Rydberg's scurf-pea | Pediomelum humile | Resolved Taxon | Wherever found | |
| Rye Cove Cave isopod | Lirceus culveri | Resolved Taxon | Wherever found | |
| Ryukyu rabbit | Pentalagus furnessi | Endangered | Japan (Ryukyu Islands) | 07-27-1979 |
| Ryukyu sika deer | Cervus nippon keramae | Endangered | Wherever found | 07-27-1979 |
| Sabinal prairie-clover | Dalea sabinalis | Species of Concern | Wherever found | |
| Sabine Map Turtle | Graptemys ouachitensis sabinensis | Resolved Taxon | Wherever found | |
| Sabine Shiner | Notropis sabinae | Not Listed | | |
| Sabino Canyon damselfly | Argia sabino | Under Review | Sabino Canyon | |
| Sablefish | Anoplopoma fimbria | Not Listed | | |
| Sacramento anthicid | Anthicus sacramento | Species of Concern | Wherever found | |
| Sacramento mountain salamander | Aneides hardii | Species of Concern | Wherever found | |
| Sacramento Mountains checkerspot Butterfly | Euphydryas anicia cloudcrofti | Endangered | Wherever found | 03-02-2023 |
| Sacramento Mountains thistle | Cirsium vinaceum | Threatened | Wherever found | 06-16-1987 |
| Sacramento Orcutt grass | Orcuttia viscida | Endangered | Wherever found | 03-26-1997 |
| Sacramento perch | Archoplites interruptus | Species of Concern | Wherever found | |
| Sacramento Pikeminnow | Ptychocheilus grandis | Not Listed | | |
| Sacramento prickly poppy | Argemone pleiacantha ssp. pinnatisecta | Endangered | Wherever found | 08-24-1989 |
| Sacramento saltbush | Atriplex persistens | Status Undefined | Wherever found | |
| Sacramento splittail | Pogonichthys macrolepidotus | Resolved Taxon | Wherever found | |
| Sacramento Sucker | Catostomus occidentalis | Not Listed | | |
| Sacramento Valley tiger beetle | Cicindela hirticollis abrupta | Resolved Taxon | Wherever found | |
| Saddleback Darter | Percina vigil | Not Listed | | |
| Saddled madtom | Noturus fasciatus | Not Listed | saddled | |
| Saddle Mountain bittercress | Cardamine pattersonii | Species of Concern | Wherever found | |
| Saddle Mountain saxifrage | Micranthes hitchcockiana | Species of Concern | Wherever found | |
| Sagebrush Sparrow | Artemisiospiza nevadensis | Species of Concern | | |
| Sagehen Creek goeracean caddisfly | Goeracea oregona | Species of Concern | Wherever found | |
| Sage-like loeflingia | Loeflingia squarrosa artemisiarum | Resolved Taxon | Wherever found | |
| Sage Thrasher | Oreoscoptes montanus | Species of Concern | Wherever found | |
| Saimaa seal | Phoca hispida saimensis | Endangered | Wherever found | 05-06-1993 |
| Saint Francis' satyr butterfly | Neonympha mitchellii francisci | Endangered | Wherever found | 04-18-1994 |
| Saint Paul cave beetle | Pseudanophthalmus sanctipauli | Not Listed | Wherever found | |
| Saiya | Amoreuxia gonzalezii | Under Review | Wherever found | |
| Sakhalin sturgeon | Acipenser mikadoi | Endangered | Wherever found | 09-04-2014 |
| Salado Salamander | Eurycea chisholmensis | Threatened | Wherever found | 03-26-2014 |
| Salamander mussel | Simpsonaias ambigua | Proposed Endangered | Wherever found | |
| salina mucket | Potamilus metnecktayi | Proposed Endangered | Wherever found | |
| Salinas Peak Woodlandsnail | Ashmunella salinasensis | Resolved Taxon | Wherever found | |
| Salinas pocket mouse | Perognathus inornatus psammophilus | Species of Concern | Wherever found | |
| Salinas Valley baeria | Lasthenia leptalea | Resolved Taxon | Wherever found | |
| Salinas Valley popcornflower | Plagiobothrys uncinatus | Species of Concern | Wherever found | |
| Saline Burrowing crayfish | Fallicambarus strawni | Status Undefined | Wherever found | |
| Saline Valley phacelia | Phacelia amabilis | Species of Concern | Wherever found | |
| Saline Valley snow-front june beetle | Polyphylla anteronivea | Species of Concern | Wherever found | |
| Salmon-crested cockatoo | Cacatua moluccensis | Threatened | Wherever found | 06-27-2011 |
| Salmon Mountains wake robin | Trillium ovatum oettingeri | Resolved Taxon | Wherever found | |
| Salt Creek Pupfish | Cyprinodon salinus | Not Listed | | |
| Salt Creek Tiger beetle | Cicindela nevadica lincolniana | Endangered | Wherever found | 10-06-2005 |
| Salt Gulch pocket gopher | Thomomys umbrinus powelli | Species of Concern | Wherever found | |
| Salt marsh bird's-beak | Cordylanthus maritimus ssp. maritimus | Endangered | Wherever found | 10-29-1978 |
| Saltmarsh Cordgrass | Spartina alterniflora | Not Listed | | |
| Salt marsh harvest mouse | Reithrodontomys raviventris | Endangered | wherever found | 10-13-1970 |
| Salt marsh ornate shrew | Sorex ornatus salicornicus | Species of Concern | Wherever found | |
| Saltmarsh Sparrow | Ammospiza caudacuta | Species of Concern | Wherever found | |
| Saltmarsh topminnow | Fundulus jenkinsi | Not Listed | Wherever found | |
| Salt marsh vagrant shrew | Sorex vagrans halicoetes | Species of Concern | Wherever found | |
| Saltwater crocodile | Crocodylus porosus | Endangered | Wherever found, except Papua New Guinea and Australia | 12-18-1979 |
| Saltwater crocodile | Crocodylus porosus | Threatened | Australia | 06-24-1996 |
| Saluda crayfish | Distocambarus youngineri | Under Review | Wherever found | |
| Samoana tree snail | Samoana conica | Species of Concern | Wherever found | |
| Samoan fruit bat | Pteropus samoensis samoensis | Resolved Taxon | Wherever found | |
| Sampson's pearlymussel | Epioblasma sampsoni | Extinction | Wherever found | 06-14-1976 |
| Samwell Cave cricket | Pristoceuthophilus sp. | Species of Concern | Wherever found | |
| San Agustin Mountainsnail | Oreohelix litoralis | Resolved Taxon | Wherever found | |
| san andreas woodlandsnail | Ashmunella kochii | Under Review | Wherever found | |
| San Antonio Hills monardella | Monardella antonina | Resolved Taxon | Wherever found | |
| San Antonio pocket gopher | Thomomys umbrinus curtatus | Species of Concern | Wherever found | |
| San Benito evening-primrose | Camissonia benitensis | Recovery | Wherever found | 02-12-1985 |
| San Benito fritillary | Fritillaria viridea | Species of Concern | Wherever found | |
| San Benito monardella | Monardella antonina ssp. benitensis | Resolved Taxon | Wherever found | |
| San Benito spineflower | Chorizanthe biloba immemora | Species of Concern | Wherever found | |
| San Benito thornmint | Acanthomintha obovata obovata | Species of Concern | Wherever found | |
| San Bernardino birds-beak | Cordylanthus eremicus bernardinus | Resolved Taxon | Wherever found | |
| San Bernardino bluegrass | Poa atropurpurea | Endangered | Wherever found | 10-14-1998 |
| San Bernardino butterweed | Packera bernardina | Species of Concern | Wherever found | |
| San Bernardino dusky shrew | Sorex monticolus parvidens | Resolved Taxon | Wherever found | |
| San Bernardino Merriam's kangaroo rat | Dipodomys merriami parvus | Endangered | Wherever found | 01-27-1998 |
| San Bernardino mountain king snake | Lampropeltis zonata parvirubra | Species of Concern | Wherever found | |
| San Bernardino Mountains bladderpod | Lesquerella kingii ssp. bernardina | Endangered | Wherever found | 08-24-1994 |
| San Bernardino Mountains dudleya | Dudleya abramsii affinis | Species of Concern | Wherever found | |
| San Bernardino Mountains grasshopper | Trimerotropis bernardi | Resolved Taxon | Wherever found | |
| San Bernardino Mountains monkey-flower | Mimulus exiguus | Species of Concern | Wherever found | |
| San Bernardino Mountains orthocarpus | Castilleja lasiorhyncha | Species of Concern | Wherever found | |
| San Bernardino northern flying squirrel | Glaucomys sabrinus californicus | Resolved Taxon | Wherever found | |
| San Bernardino ringneck snake | Diadophis punctatus modestus | Species of Concern | Wherever found | |
| San Bernardino rock-cress | Arabis breweri pecuniaria | Species of Concern | Wherever found | |
| San Bernardino springsnail | Pyrgulopsis bernardina | Threatened | Wherever found | 05-17-2012 |
| San Bruno elfin butterfly | Callophrys mossii bayensis | Endangered | Wherever found | 06-08-1976 |
| San Bruno Mountain manzanita | Arctostaphylos imbricata | Resolved Taxon | Wherever found | |
| San Carlos wild-buckwheat | Eriogonum capillare | Species of Concern | Wherever found | |
| San Clemente Bewick's wren | Thryomanes bewickii leucophrys | Resolved Taxon | Wherever found | |
| San Clemente deer mouse | Peromyscus maniculatus clementis | Species of Concern | Wherever found | |
| San Clemente island bedstraw | Galium catalinense acrispum | Species of Concern | Wherever found | |
| San Clemente Island blunt-top snail | Sterkia clementina | Resolved Taxon | Wherever found | |
| San Clemente Island brodiaea | Brodiaea kinkiensis | Species of Concern | Wherever found | |
| San Clemente Island brodiaea | Triteleia clementina | Species of Concern | Wherever found | |
| San Clemente Island buckwheat | Eriogonum giganteum formosum | Species of Concern | Wherever found | |
| San Clemente Island bush-mallow | Malacothamnus clementinus | Recovery | Wherever found | 09-12-1977 |
| San Clemente Island coenonycha beetle | Coenonycha clementina | Species of Concern | Wherever found | |
| San Clemente Island evening-primrose | Camissonia guadalupensis clementina | Species of Concern | Wherever found | |
| San Clemente Island fox | Urocyon littoralis clementae | Species of Concern | Wherever found | |
| San Clemente Island larkspur | Delphinium variegatum ssp. kinkiense | Recovery | Wherever found | 09-12-1977 |
| San Clemente Island lotus (=broom) | Acmispon dendroideus var. traskiae | Recovery | Wherever found | 09-12-1977 |
| San Clemente Island milk-vetch | Astragalus nevinii | Species of Concern | Wherever found | |
| San Clemente Island Paintbrush | Castilleja grisea | Recovery | Wherever found | 09-12-1977 |
| San Clemente islandsnail | Micrarionta gabbii | Species of Concern | Wherever found | |
| San Clemente Island woodland-star | Lithophragma maximum | Endangered | Wherever found | 08-08-1997 |
| San Clemente loggerhead shrike | Lanius ludovicianus mearnsi | Endangered | Wherever found | 09-12-1977 |
| San Clemente sage sparrow | Amphispiza belli clementeae | Recovery | Wherever found | 09-12-1977 |
| Sandbank Pocketbook | Lampsilis satura | Not Listed | | |
| Sandbar, inside-outside willow | Salix interior exterior | Resolved Taxon | Wherever found | |
| Sand cholla | Opuntia pulchella | Resolved Taxon | Wherever found | |
| Sand dune phacelia | Phacelia argentea | Threatened | | 09-21-2023 |
| Sanderson's Cheesebush | Hymenoclea sandersonii | Resolved Taxon | Wherever found | |
| Sand flax | Linum arenicola | Endangered | | 10-31-2016 |
| Sandfood | Pholisma sonorae | Species of Concern | Wherever found | |
| Sand gazelle | Gazella subgutturosa marica | Endangered | Wherever found | 07-27-1979 |
| Sandhill four-o'clock | Mirabilis nyctaginea | Species of Concern | Wherever found | |
| Sandhill goosefoot | Chenopodium cycloides | Species of Concern | Wherever found | |
| Sandhills chub | Semotilus lumbee | Resolved Taxon | Wherever found | |
| Sandhills clubtail | Gomphus parvidens carolinus | Species of Concern | Wherever found | |
| Sandhills milk-vetch | Astragalus michauxii | Species of Concern | Wherever found | |
| San Diego ambrosia | Ambrosia pumila | Endangered | Wherever found | 07-02-2002 |
| San Diego banded gecko | Coleonyx variegatus abbotti | Species of Concern | Wherever found | |
| San Diego black-tailed jackrabbit | Lepus californicus bennettii | Species of Concern | Wherever found | |
| San Diego button-celery | Eryngium aristulatum var. parishii | Endangered | Wherever found | 08-03-1993 |
| San Diego cactus wren | Campylorhynchus brunneicapillus couesi | Resolved Taxon | Wherever found | |
| San Diego County viguiera | viguiera laciniata | Species of Concern | Wherever found | |
| San Diego desert woodrat | Neotoma lepida intermedia | Species of Concern | Wherever found | |
| San Diego fairy shrimp | Branchinecta sandiegonensis | Endangered | Wherever found | 02-03-1997 |
| San Diego goldenstar | Muilla clevelandii | Species of Concern | Wherever found | |
| San Diego horned lizard | Phrynosoma coronatum blainvillii | Species of Concern | Wherever found | |
| San Diego marsh elder | Iva hayesiana | Species of Concern | Wherever found | |
| San Diego mesa-mint | Pogogyne abramsii | Endangered | Wherever found | 10-29-1978 |
| San Diego Mountain king snake | Lampropeltis zonata pulchra | Species of Concern | Wherever found | |
| San Diego ringneck snake | Diadophis punctatus similis | Species of Concern | Wherever found | |
| San Diego sagewort | artemisia palmeri | Species of Concern | Wherever found | |
| San Diego thornmint | Acanthomintha ilicifolia | Threatened | Wherever found | 10-13-1998 |
| Sandlace | Polygonella myriophylla | Endangered | | 04-27-1993 |
| Sand linanthus | Linanthus arenicola | Resolved Taxon | Wherever found | |
| Sand-loving wild-buckwheat | Eriogonum ammophilum | Resolved Taxon | Wherever found | |
| Sandmat manzanita | Arctostaphylos pumila | Species of Concern | Wherever found | |
| Sand mesa manzanita | Arctostaphylos rudis | Species of Concern | Wherever found | |
| Sand Mountain aphodius scarab | Aphodius sp. | Species of Concern | Sand Mt. | |
| Sand Mountain blue | Euphilotes rita ssp. | Species of Concern | Wherever found | |
| Sand Mountain blue butterfly | Euphilotes pallescens arenamontana | Resolved Taxon | Wherever found | |
| Sand Mountain serican scarab | Serica psammobunus | Resolved Taxon | Wherever found | |
| Sandplain gerardia | Agalinis acuta | Endangered | Wherever found | 09-07-1988 |
| Sand prickly-pear | Opuntia arenaria | Species of Concern | Wherever found | |
| Sand Roller | Percopsis transmontana | Not Listed | | |
| Sand sacahuista | Nolina arenicola | Species of Concern | Wherever found | |
| Sand Shiner | Notropis stramineus | Not Listed | | |
| Sand skink | Neoseps reynoldsi | Threatened | Wherever found | 11-06-1987 |
| Sandstone night lizard | Xantusia gracilis | Resolved Taxon | Wherever found | |
| Sandstone wild-buckwheat | Eriogonum jamesii rupicola | Resolved Taxon | Wherever found | |
| Sand-verbena moth | Copablepharon fuscum | Resolved Taxon | Wherever found | |
| Sand wasp | Microbembex elegans | Resolved Taxon | Wherever found | |
| Sand wasp | Stictiella villegasi | Resolved Taxon | Wherever found | |
| Sandwich Tern | Thalasseus sandvicensis | Species of Concern | Wherever found | |
| Sandy beach tiger beetle | Cicindela hirticollis gravida | Species of Concern | Wherever found | |
| San Emigdio blue | Plebulina emigdionis | Species of Concern | Wherever found | |
| San Esteban Island chuckwalla | Sauromalus varius | Endangered | Wherever found | 03-20-1980 |
| San Felipe gambusia | Gambusia clarkhubbsi | Resolved Taxon | Wherever found | |
| San Felipe monardella | Monardella nana leptosiphon | Species of Concern | Wherever found | |
| San Fernando Valley Spineflower | Chorizanthe parryi var. fernandina | Resolved Taxon | | |
| Sanford Talussnail | Sonorella tryoniana | Resolved Taxon | Wherever found | |
| San Francisco Bay spineflower | Chorizanthe cuspidata cuspidata | Species of Concern | Wherever found | |
| San Francisco collinsia | collinsia multicolor | Species of Concern | Wherever found | |
| San Francisco dusky-footed woodrat | Neotoma fuscipes annectens | Species of Concern | Wherever found | |
| San Francisco forktail damselfly | Ischnura gemina | Resolved Taxon | Wherever found | |
| San Francisco garter snake | Thamnophis sirtalis tetrataenia | Endangered | Wherever found | 03-11-1967 |
| San Francisco gumplant | Grindelia hirsuta maritima | Species of Concern | Wherever found | |
| San Francisco lacewing | Nothochrysa californica | Species of Concern | Wherever found | |
| San Francisco lessingia | Lessingia germanorum (=L.g. var. germanorum) | Endangered | Wherever found | 06-19-1997 |
| San Francisco owl's-clover | Triphysaria floribunda | Species of Concern | Wherever found | |
| San Francisco Peaks ragwort | Packera franciscana | Threatened | Wherever found | 11-22-1983 |
| San Francisco popcornflower | Plagiobothrys torreyi var. diffusus | Species of Concern | Wherever found | |
| San Francisco tree lupine moth | Grapholita edwardsiana | Resolved Taxon | Wherever found | |
| San Francisco wallflower | Erysimum franciscanum | Species of Concern | Wherever found | |
| San Gabriel bedstraw | Galium grande | Species of Concern | Wherever found | |
| San Gabriel chestnut snail | Glyptostoma gabrielense | Status Undefined | | |
| San Gabriel manzanita | Arctostaphylos gabrielensis | Species of Concern | Wherever found | |
| San Gabriel Mountains blue | Plejebus saepiolus ssp. | Species of Concern | San Gabriel Mts | |
| San Gabriel Mountains dudleya | Dudleya densiflora | Resolved Taxon | Wherever found | |
| San Gabriel Mountains elfin | Incisalia mossii ssp. | Species of Concern | San Gabriel | |
| San Gabriel River dudleya | Dudleya cymosa crebrifolia | Species of Concern | Wherever found | |
| Sangre de Cristo peaclam | Pisidium sanguinichristi | Under Review | Wherever found | |
| Sanibel Island rice rat | Oryzomys palustris sanibeli | Under Review | Wherever found | |
| Sanibel love grass | Eragrostis pectinacea | Species of Concern | Wherever found | |
| San Jacinto bedstraw | Galium californicum primum | Species of Concern | Wherever found | |
| San Jacinto Mountains bedstraw | galium angustifolium ssp. jacinticum | Species of Concern | Wherever found | |
| San Jacinto Mountains chia | Salvia columbariae ziegleri | Resolved Taxon | Wherever found | |
| San Jacinto prickly-phlox | Leptodactylon jaegeri | Resolved Taxon | Wherever found | |
| San Jacinto Valley crownscale | Atriplex coronata var. notatior | Endangered | Wherever found | 10-13-1998 |
| San Joaquin adobe sunburst | Pseudobahia peirsonii | Threatened | Wherever found | 02-06-1997 |
| San Joaquin dune beetle | Coelus gracilis | Resolved Taxon | Wherever found | |
| San Joaquin kit fox | Vulpes macrotis mutica | Endangered | wherever found | 03-11-1967 |
| San Joaquin LeConte's thrasher | Toxostoma lecontei macmillanorum | Species of Concern | Wherever found | |
| San Joaquin pocket mouse | Perognathus inornatus | Species of Concern | Wherever found | |
| San Joaquin pocket mouse | Perognathus inornatus inornatus | Resolved Taxon | Wherever found | |
| San Joaquin tiger beetle | Cicindela tranquebarica ssp. | Species of Concern | Wherever found | |
| San Joaquin Valley giant flower-loving fly | Rhaphiomidas trochilus | Under Review | Wherever found | |
| San Joaquin Valley Orcutt grass | Orcuttia inaequalis | Threatened | Wherever found | 03-26-1997 |
| San Joaquin whipsnake | Masticophis flagellum ruddocki | Species of Concern | Wherever found | |
| San Joaquin wooly-threads | Monolopia (=Lembertia) congdonii | Endangered | Wherever found | 07-19-1990 |
| San Juan milkweed | Asclepias sanjuanensis | Resolved Taxon | Wherever found | |
| San Luis lupine | Lupinus ludovicianus | Species of Concern | Wherever found | |
| San Luis mariposa | Calochortus obispoensis | Resolved Taxon | Wherever found | |
| San Luis Obispo monardella | Monardella frutescens | Species of Concern | Wherever found | |
| San Luis sedge | Carex obispoensis | Resolved Taxon | Wherever found | |
| San Luis serpentine dudleya | Dudleya abramsii bettinae | Species of Concern | Wherever found | |
| San Luis watercress | Rorippa coloradensis | Species of Concern | Wherever found | |
| San Marcos gambusia | Gambusia georgei | Extinction | Wherever found | 07-14-1980 |
| San Marcos saddle-case caddisfly | Protoptila arca | Resolved Taxon | Wherever found | |
| San Marcos salamander | Eurycea nana | Threatened | Wherever found | 07-14-1980 |
| San Mateo thornmint | Acanthomintha obovata ssp. duttonii | Endangered | Wherever found | 09-18-1985 |
| San Mateo woolly sunflower | Eriophyllum latilobum | Endangered | Wherever found | 02-03-1995 |
| San Miguel Island bedstraw | Galium californicum miguelense | Resolved Taxon | Wherever found | |
| San Miguel Island buckwheat | Eriogonum grande dunklei | Resolved Taxon | Wherever found | |
| San Miguel Island Fox | Urocyon littoralis littoralis | Recovery | wherever found | 03-05-2004 |
| San Miguel savory | Clinopodium chandleri | Resolved Taxon | Wherever found | |
| San Nicolas Island buckwheat | Eriogonum grande timorum | Species of Concern | Wherever found | |
| San Nicolas Island desert-thorn | Lycium verrucosum | Resolved Taxon | Wherever found | |
| San Nicolas Island fox | Urocyon littoralis dickeyi | Species of Concern | Wherever found | |
| San Nicolas Island lomatium | Lomatium insulare | Species of Concern | Wherever found | |
| San Nicolas islandsnail | Micrarionta feralis | Species of Concern | Wherever found | |
| San Pablo California vole | Microtus californicus sanpabloensis | Resolved Taxon | Wherever found | |
| san pedro river wild buckwheat | eriogonum terrenatum | Resolved Taxon | Wherever found | |
| San Pitch Valley milk-vetch | Astragalus lentiginosus chartaceus | Resolved Taxon | Wherever found | |
| San Rafael cactus | Pediocactus despainii | Endangered | Wherever found | 09-16-1987 |
| San Rafael milk-vetch | Astragalus rafaelensis | Resolved Taxon | Wherever found | |
| Santa Ana River woolly-star | Eriastrum densifolium ssp. sanctorum | Endangered | Wherever found | 09-28-1987 |
| Santa Ana speckled dace | Rhinichthys gabrielino | Proposed Threatened | Santa Ana | |
| Santa Ana sucker | Catostomus santaanae | Threatened | Los Angeles River basin, San Gabriel River basin, Santa Ana River basin | 04-12-2000 |
| Santa Ana threespine stickleback | Gasterosteus aculeatus santaannae | Resolved Taxon | Wherever found | |
| Santa Barbara false-lupine | Thermopsis macrophylla agnina | Species of Concern | Wherever found | |
| Santa Barbara Island buckwheat | Eriogonum giganteum compactum | Species of Concern | Wherever found | |
| Santa Barbara Island cream cups | Platystemon californicus ciliatus | Species of Concern | Wherever found | |
| Santa Barbara Island liveforever | Dudleya traskiae | Endangered | Wherever found | 05-27-1978 |
| Santa Barbara islandsnail | Micrarionta facta | Species of Concern | Wherever found | |
| Santa Barbara jewelflower | Caulanthus amplexicaulis barbarae | Resolved Taxon | Wherever found | |
| Santa Barbara shelled slug | Binneya notabilis | Species of Concern | Wherever found | |
| Santa Barbara Song Sparrow | Melospiza melodia graminea | Extinction | Wherever found | 06-04-1973 |
| Santa Catalina figwort | Scrophularia villosa | Species of Concern | Wherever found | |
| Santa Catalina Island desert-thorn | Lycium hassei | Species of Concern | Wherever found | |
| Santa Catalina Island Fox | Urocyon littoralis catalinae | Threatened | Wherever found | 03-05-2004 |
| Santa Catalina Island manzanita | Arctostaphylos catalinae | Species of Concern | Wherever found | |
| Santa Catalina Island trigonscuta weevil | Trigonoscuta catalina | Species of Concern | Wherever found | |
| Santa Catalina monkey-flower | Mimulus traskiae | Species of Concern | Wherever found | |
| Santa Catalina Mountains squirrel | Sciurus arizonensis catalinae | Species of Concern | Wherever found | |
| Santa Catalina Mountains woodrat | Neotoma mexicana bullata | Species of Concern | Wherever found | |
| Santa Catalina ornate shrew | Sorex ornatus willetti | Species of Concern | Wherever found | |
| Santa Clara Valley dudleya | Dudleya setchellii | Endangered | Wherever found | 02-03-1995 |
| Santa Cruz beehive cactus | Coryphantha recurvata | Species of Concern | Wherever found | |
| Santa Cruz cypress | Cupressus abramsiana | Threatened | Wherever found | 01-08-1987 |
| Santa Cruz gooseberry | Ribes thacherianum | Species of Concern | Wherever found | |
| Santa Cruz harvest mouse | Reithrodontomys megalotis santacruzae | Resolved Taxon | Wherever found | |
| Santa Cruz Island bush-mallow | Malacothamnus fasciculatus var. nesioticus | Endangered | Wherever found | 07-31-1997 |
| Santa Cruz Island dudleya | Dudleya nesiotica | Recovery | Wherever found | 07-31-1997 |
| Santa Cruz Island Fox | Urocyon littoralis santacruzae | Recovery | wherever found | 03-05-2004 |
| Santa Cruz Island fringepod | Thysanocarpus conchuliferus | Endangered | Wherever found | 07-31-1997 |
| Santa Cruz Island gopher snake | Pituophis melanoleucus pumilis | Species of Concern | Wherever found | |
| Santa Cruz Island malacothrix | Malacothrix indecora | Endangered | Wherever found | 07-31-1997 |
| Santa Cruz Island monkey-flower | Mimulus brandegeei | Species of Concern | Wherever found | |
| Santa Cruz Island oak | Quercus parvula | Resolved Taxon | Wherever found | |
| Santa Cruz Island rockcress | Sibara filifolia | Endangered | Wherever found | 08-08-1997 |
| Santa Cruz Island shore weevil | Trigonoscuta stantoni | Species of Concern | Wherever found | |
| Santa Cruz long-toed salamander | Ambystoma macrodactylum croceum | Endangered | Wherever found | 03-11-1967 |
| Santa Cruz manzanita | Arctostaphylos andersonii | Species of Concern | Wherever found | |
| Santa Cruz rain beetle | Pleocoma conjugens conjugens | Resolved Taxon | Wherever found | |
| Santa Cruz silverpuffs | Stebbinsoseris decipiens | Species of Concern | Wherever found | |
| Santa Cruz star leaf | Choisya mollis | Species of Concern | Wherever found | |
| Santa Cruz striped agave | Agave parviflora parviflora | Species of Concern | Wherever found | |
| Santa Cruz tarplant | Holocarpha macradenia | Threatened | Wherever found | 03-20-2000 |
| Santa Cruz telemid spider | Telema sp. | Species of Concern | Wherever found | |
| Santa Fe Cave crayfish | Procambarus erythrops | Under Review | Wherever found | |
| Santa Fe cholla | Opuntia viridiflora | Species of Concern | Wherever found | |
| Santa Lucia bedstraw | Galium clementis | Resolved Taxon | Wherever found | |
| Santa Lucia lupine | Lupinus cervinus | Resolved Taxon | Wherever found | |
| Santa Lucia manzanita | Arctostaphylos luciana | Species of Concern | Wherever found | |
| Santa Lucia pogogyne | Pogogyne clareana | Species of Concern | Wherever found | |
| Santa Margarita manzanita | Arctostaphylos pilosula pilosula | Species of Concern | Wherever found | |
| Santa Monica Mountains dudleyea | Dudleya cymosa ssp. ovatifolia | Threatened | Wherever found | 01-29-1997 |
| Santa Monica Mountains grasshopper | Trimerotropis occidentiloides | Resolved Taxon | Wherever found | |
| Santa Monica Mountains hairstreak | Satyrium auretorum fumosum | Resolved Taxon | Wherever found | |
| Santa Monica shieldback katydid | Neduba longipennis | Species of Concern | Wherever found | |
| Santa Paula buckwheat | Eriogonum parvifolium paynei | Resolved Taxon | Wherever found | |
| Santa Rita Mountains chlorochroan bug | Chlorochroa rita | Species of Concern | Wherever found | |
| Santa Rita rabdotus | Naesiotus christenseni | Resolved Taxon | Wherever found | |
| Santa Rosa beach mouse | Peromyscus polionotus leucocephalus | Species of Concern | Wherever found | |
| Santa Rosa Island dudleya | Dudleya blochmaniae insularis | Resolved Taxon | Wherever found | |
| Santa Rosa Island Fox | Urocyon littoralis santarosae | Recovery | wherever found | 03-05-2004 |
| Santa Rosa Island manzanita | Arctostaphylos confertiflora | Endangered | Wherever found | 07-31-1997 |
| Santa Rosa linderiella | Linderiella santarosae | Species of Concern | Wherever found | |
| Santa Susana tarweed | Hemizonia minthornii | Species of Concern | Wherever found | |
| Santiago Peak phacelia | Phacelia suaveolens keckii | Species of Concern | Wherever found | |
| San Xavier talussnail | Sonorella eremita | Resolved Taxon | Wherever found | |
| Sao Miguel bullfinch (finch) | Pyrrhula pyrrhula murina | Endangered | Wherever found | 06-02-1970 |
| Sapphire Mt. rock-cress | Arabis fecunda | Species of Concern | Wherever found | |
| Sarah's hydroptila caddisfly | Hydroptila sarahae | Resolved Taxon | Wherever found | |
| Saratoga Springs belostoman bug | Belostoma saratogae | Species of Concern | Wherever found | |
| Saratogoa Springs Pupfish | Cyprinodon nevadensis nevadensis | Not Listed | | |
| Satellus yellow-faced bee | Hylaeus satellus | Species of Concern | Wherever found | |
| Saudi Arabian gazelle | Gazella dorcas saudiya | Endangered | Wherever found | 07-27-1979 |
| Sauger | Sander canadensis | Not Listed | | |
| Savannah campylopus | Campylopus carolinae | Species of Concern | Wherever found | |
| Savannah lilliput | Toxolasma pullus | Status Undefined | Wherever found | |
| Savannah pebblesnail | Somatogyrus tenax | Species of Concern | Wherever found | |
| Sawback angelshark | Squatina aculeata | Endangered | | 03-31-2016 |
| Sawmill Hollow cave beetle | Pseudanophthalmus scholasticus | Species of Concern | Wherever found | |
| Saw-toothed lewisia | Lewisia serrata | Species of Concern | Wherever found | |
| Sawtooth Mountain woodlandsnail | Ashmunella mudgei | Resolved Taxon | Wherever found | |
| Saxicola rock catfoot | Gnaphalium obtusifolium saxicola | Species of Concern | Wherever found | |
| Say's spiketail | Cordulegaster sayi | Status Undefined | Wherever found | |
| Scabrid railardella | Anisocarpus scabridus | Resolved Taxon | Wherever found | |
| Scadden Flat checkerbloom | Sidalcea stipularis | Species of Concern | Wherever found | |
| Scaled Quail | Callipepla squamata | Species of Concern | Wherever found | |
| Scaleshell mussel | Leptodea leptodon | Endangered | Wherever found | 10-09-2001 |
| Scalloped Hammerhead Shark | Sphyrna lewini | Endangered | Eastern Atlantic DPS | 09-02-2014 |
| Scalloped Hammerhead Shark | Sphyrna lewini | Endangered | Eastern Pacific DPS | 09-02-2014 |
| Scalloped Hammerhead Shark | Sphyrna lewini | Threatened | Central and Southwest Atlantic DPS | 09-02-2014 |
| Scalloped Hammerhead Shark | Sphyrna lewini | Threatened | Indo-West Pacific DPS | 09-02-2014 |
| Scaly rhyncogonus weevil | Rhyncogonus squamiger | Species of Concern | Wherever found | |
| Scaly-tailed possum | Wyulda squamicaudata | Endangered | Wherever found | 12-02-1970 |
| Scarlet-breasted robin (flycatcher) | Petroica multicolor multicolor | Endangered | Wherever found | 06-02-1970 |
| Scarlet catchfly | Silene subciliata | Species of Concern | Wherever found | |
| Scarlet-chested parakeet | Neophema splendida | Recovery | Wherever found | 12-02-1970 |
| Scarlet macaw | Ara macao ssp. cyanopterus | Endangered | Wherever found | 03-28-2019 |
| Scarlet macaw | Ara macao ssp. macao | Similarity of Appearance (Threatened) | Southern DPS | 03-28-2019 |
| Scarlet macaw | Ara macao ssp. macao | Threatened | Northern DPS | 03-30-2023 |
| Scarlet Tanager | Piranga olivacea | Species of Concern | | |
| Schauinsland's bush cricket | Caconemobius schauinslandi | Species of Concern | Wherever found | |
| Schaum's Blue Ridge ground beetle | Sphaeroderus schaumi | Species of Concern | Wherever found | |
| Schaus swallowtail butterfly | Heraclides aristodemus ponceanus | Endangered | Wherever found | 04-28-1976 |
| Schell Creek mountainsnail | Oreohelix nevadensis | Species of Concern | Wherever found | |
| Schleser's fishhook cactus | Sclerocactus schleseri | Species of Concern | Wherever found | |
| Schoolcraft's cryptantha | Cryptantha sobolifera | Species of Concern | Wherever found | |
| Schoolhouse Springs leuctran stonefly | Leuctra szczytkoi | Under Review | Wherever found | |
| Schott's wire-lettuce | Stephanomeria schottii | Resolved Taxon | Wherever found | |
| Schreiber's manzanita | Arabis oxylobula | Resolved Taxon | Wherever found | |
| Schreiber's manzanita | Arctostaphylos glutinosa | Species of Concern | Wherever found | |
| Schuh's homoplectran caddisfly | Homoplectra schuhi | Species of Concern | Wherever found | |
| Schwarz' diving beetle | Laccophilus schwarzi | Resolved Taxon | Wherever found | |
| Schweinitz's sunflower | Helianthus schweinitzii | Endangered | Wherever found | 05-07-1991 |
| Schweinitz's waterweed | Elodea schweinitzii | Species of Concern | Wherever found | |
| Scimitar-horned oryx | Oryx dammah | Endangered | Wherever found | 09-02-2005 |
| Scioto madtom | Noturus trautmani | Extinction | Wherever found | 10-28-1975 |
| Scissor-tailed Flycatcher | Tyrannus forficatus | Species of Concern | Wherever found | |
| Sclater's monal pheasant | Lophophorus sclateri | Endangered | Wherever found | 06-02-1970 |
| Scott Bar salamander | Plethodon asupak | Resolved Taxon | Wherever found | |
| Scott Mountains bedstraw | Galium serpenticum scotticum | Resolved Taxon | Wherever found | |
| Scott optioservus riffle beetle | Optioservus phaeus | Resolved Taxon | Wherever found | |
| Scott's Oriole | Icterus parisorum | Species of Concern | | |
| Scott's spleenwort | Asplenium ebenoides | Resolved Taxon | Wherever found | |
| Scotts Valley Polygonum | Polygonum hickmanii | Endangered | Wherever found | 04-08-2003 |
| Scotts Valley spineflower | Chorizanthe robusta var. hartwegii | Endangered | Wherever found | 02-04-1994 |
| Scott Valley phacelia | Phacelia greenei | Species of Concern | Wherever found | |
| Scribe allocarya | Plagiobothrys scriptus | Resolved Taxon | Wherever found | |
| Scripp's Murrelet | Synthliboramphus hypoleucus scrippsi | Resolved Taxon | Wherever found | |
| Scripps's Murrelet | Synthliboramphus scrippsi | Species of Concern | | |
| Scrub blazingstar | Liatris ohlingerae | Endangered | | 07-27-1989 |
| Scrub buckwheat | Eriogonum longifolium var. gnaphalifolium | Threatened | | 04-27-1993 |
| Scrub golden aster noctuid moth | Schinia rufipenna | Species of Concern | Wherever found | |
| Scrub Island burrowing scarab | Mycotrupes pedester | Species of Concern | Wherever found | |
| Scrub lupine | Lupinus aridorum | Endangered | | 04-07-1987 |
| Scrub mint | Dicerandra frutescens | Endangered | | 11-01-1985 |
| Scrub oak | Quercus berberidifolia | Species of Concern | Wherever found | |
| Scrub palmetto flower scarab | Trigonopelastes floridana | Species of Concern | Wherever found | |
| Scrub plum | Prunus geniculata | Endangered | | 01-21-1987 |
| Sculpin snail | Stiobia nana | Species of Concern | Wherever found | |
| Sculpted supercoil | Paravitrea ternaria | Species of Concern | Wherever found | |
| Sculptured popcornflower | Plagiobothrys glyptocarpus var. glyptocarpus | Species of Concern | Wherever found | |
| Scup | Stenotomus chrysops | Not Listed | | |
| Seabeach amaranth | Amaranthus pumilus | Threatened | Wherever found | 04-07-1993 |
| sea bean | Mucuna persericea | Endangered | Wherever found | 06-27-2013 |
| Sea cliff bluegrass | Poa unilateralis | Resolved Taxon | Wherever found | |
| Sea Lamprey | Petromyzon marinus | Species of Concern | | |
| Sea Otter | Enhydra lutris | Not Listed | | |
| Searchlight southern pocket gopher | Thomomys umbrinus suboles | Species of Concern | Wherever found | |
| Seashore cactus | Opuntia martiniana | Resolved Taxon | Wherever found | |
| Seaside alder | Alnus maritima | Resolved Taxon | Wherever found | |
| Seaside birds-beak | Cordylanthus rigidus littoralis | Species of Concern | Wherever found | |
| Seaside, Coulter's daisy | Lasthenia glabrata coulteri | Species of Concern | Wherever found | |
| Seaside goldfields | Lasthenia maritima | Resolved Taxon | Wherever found | |
| Seaside Sparrow | Ammospiza maritima fisheri | Species of Concern | | |
| Seaside Sparrow | Ammospiza maritima maritima | Species of Concern | | |
| Seaside Sparrow | Ammospiza maritima peninsulae | Species of Concern | Wherever found | |
| Seaside Sparrow | Ammospiza maritima sennetti | Species of Concern | | |
| Seaside tarweed | Hemizonia multicaulis multicaulis | Species of Concern | Wherever found | |
| Sebastopol meadowfoam | Limnanthes vinculans | Endangered | Wherever found | 12-02-1991 |
| Seclusive water scavenger beetle | Paracymus seclusus | Resolved Taxon | Wherever found | |
| Secund jewelflower | Streptanthus glandulosus hoffmanii | Species of Concern | Wherever found | |
| Sedge fescue | Festuca dasyclada | Resolved Taxon | Wherever found | |
| Sedge Wren | Cistothorus platensis | Species of Concern | Wherever found | |
| Seepage salamander | Desmognathus aeneus | Not Listed | Wherever found | |
| Sei whale | Balaenoptera borealis | Endangered | Wherever found | 06-02-1970 |
| Seledang | Bos gaurus | Endangered | Wherever found | 06-02-1970 |
| Selium wingless thread bug | Nesidiolestes selium | Species of Concern | Wherever found | |
| Seminole siltsnail | Cincinnatia vanhyningi | Species of Concern | Wherever found | |
| Semipalmated Sandpiper | Calidris pusilla | Species of Concern | Wherever found | |
| Semper's warbler (=wood) | Leucopeza semperi | Endangered | Wherever found | 06-02-1970 |
| Seneca cave beetle | Pseudanophthalmus potomaca senecae | Species of Concern | Wherever found | |
| Sennett's hooded oriole | Icterus cucullatus sennetti | Species of Concern | Wherever found | |
| Sensabush cave beetle | Pseudanophthalmus paradoxus | Species of Concern | Wherever found | |
| Sensitive joint-vetch | Aeschynomene virginica | Threatened | Wherever found | 05-20-1992 |
| Sentry milk-vetch | Astragalus cremnophylax var. cremnophylax | Endangered | Wherever found | 12-05-1990 |
| september 11 stickleaf | mentzelia memorabalis | Resolved Taxon | Wherever found | |
| Septima's clubtail | Gomphus septima | Under Review | Wherever found | |
| Sequatchie caddisfly | Glyphopsyche sequatchie | Resolved Taxon | Wherever found | |
| Sequoia gooseberry | Ribes tularensis | Species of Concern | Wherever found | |
| Sequoyah Caverns cave beetle | Pseudanophthalmus sequoyah | Species of Concern | Wherever found | |
| Serow | Naemorhedus (=Capricornis) sumatraensis | Endangered | Wherever found | 06-14-1976 |
| Serpentine aster | Symphyotrichum depauperatum | Species of Concern | Wherever found | |
| Serpentine haplopappus | Ericameria ophitidis | Resolved Taxon | Wherever found | |
| Serpentine sunflower | Helianthus exilis | Resolved Taxon | Wherever found | |
| Serpent Island gecko | Cyrtodactylus serpensinsula | Threatened | Wherever found | 06-22-1983 |
| Sessile-leaved warea | Warea sessilifolia | Resolved Taxon | Wherever found | |
| Seth Forest water scavenger beetle | Hydrochus sp. | Species of Concern | Wherever found | |
| Setose Cream and Brown Mottle microcaddisfly | Oxyethira setosa | Status Undefined | Wherever found | |
| Sevier snowfly | Allocapnia brooksi | Under Review | Wherever found | |
| Seychelles fody (weaver-finch) | Foudia sechellarum | Endangered | Wherever found | 06-02-1970 |
| Seychelles kestrel | Falco araea | Endangered | Wherever found | 06-02-1970 |
| Seychelles lesser vasa parrot | Coracopsis nigra barklyi | Endangered | Wherever found | 01-12-1995 |
| Seychelles magpie-robin (thrush) | Copsychus sechellarum | Endangered | Wherever found | 06-02-1970 |
| Seychelles paradise flycatcher | Terpsiphone corvina | Endangered | Wherever found | 06-02-1970 |
| Seychelles scops owl | Otus magicus (=insularis) insularis | Endangered | Wherever found | 06-02-1970 |
| Seychelles turtle dove | Streptopelia picturata rostrata | Endangered | Wherever found | 01-12-1995 |
| Seychelles warbler (old world warbler) | Bebrornis sechellensis | Endangered | Wherever found | 06-02-1970 |
| Seychelles white-eye | Zosterops modesta | Endangered | Wherever found | 06-02-1970 |
| Shade-winged nesomimesan sphecid wasp | Nesomimesa sciopteryx | Species of Concern | Wherever found | |
| Shaggy coil | Helicodiscus diadema | Species of Concern | Wherever found | |
| shaggyhair alumroot | Heuchera hirsutissima | Species of Concern | Wherever found | |
| Shaggy-hair lupine | Lupinus spectabilis | Species of Concern | Wherever found | |
| shaggy horkelia | Horkelia congesta ssp. congesta | Species of Concern | Wherever found | |
| Shale barren rock cress | Boechera serotina | Endangered | Wherever found | 07-13-1989 |
| Shansi sika deer | Cervus nippon grassianus | Endangered | Wherever found | 07-27-1979 |
| Shapo | Ovis vignei vignei | Endangered | Wherever found | 06-14-1976 |
| Shark Bay mouse | Pseudomys praeconis | Endangered | Wherever found | 12-02-1970 |
| Sharphead darter | Etheostoma acuticeps | Resolved Taxon | Wherever found | |
| Sharp Hornsnail | Pleurocera acuta | Not Listed | | |
| Sharpnose Shiner | Notropis oxyrhynchus | Endangered | Wherever found | 08-04-2014 |
| Sharp shinned hawk | Accipiter striatus | Species of Concern | Wherever found | |
| Sharp's leafy liverwort | Plagiochila sharpii | Status Undefined | | |
| Sharp's rhyncogonus weevil | Rhyncogonus sharpi | Species of Concern | Wherever found | |
| Sharsmth's stickseed | Hackelia sharsmithii | Resolved Taxon | Wherever found | |
| Shasta arnica | Arnica viscosa | Resolved Taxon | Wherever found | |
| Shasta chaparral | Trilobopsis roperi | Under Review | Wherever found | |
| Shasta crayfish | Pacifastacus fortis | Endangered | Wherever found | 09-30-1988 |
| Shasta eupatorium | Ageratina shastensis | Resolved Taxon | Wherever found | |
| Shasta hesperian | Vespericola shasta | Under Review | Wherever found | |
| Shasta orthocarpus | Orthocarpus pachystachyus | Resolved Taxon | Wherever found | |
| Shasta panic grass | Dichanthelium acuminatum var. acuminatum | Resolved Taxon | Wherever found | |
| Shasta pebblesnail | Fluminicola multifarius | Resolved Taxon | Wherever found | |
| Shasta River mariposa lily | Calochortus monanthus | Species of Concern | Wherever found | |
| Shasta salamander | Hydromantes shastae | Resolved Taxon | Wherever found | 05-05-2021 |
| Shasta sideband | Monadenia troglodytes troglodytes | Under Review | Wherever found | |
| Shasta Sideband | Monadenia troglodytes | Not Listed | | |
| Shasta snow-wreath | Neviusia cliftonii | Under Review | | |
| Shaw Island Townsend's vole | Microtus townsendii pugeti | Resolved Taxon | Wherever found | |
| Shawnee darter | Etheostoma tecumsehi | Under Review | Wherever found | |
| Shaw's agave | Agave shawii | Species of Concern | Wherever found | |
| Sheathed deathcamus | Zigadenus vaginatus | Resolved Taxon | Wherever found | |
| Sheath-tailed Bat | Emballonura semicaudata semicaudata | Species of Concern | Wherever found | |
| Sheepnose Mussel | Plethobasus cyphyus | Endangered | Wherever found | 04-12-2012 |
| Sheepshead | Archosargus probatocephalus | Not Listed | | |
| Sheldon tui chub | Siphateles bicolor eurysoma | Species of Concern | Wherever found | |
| Shelled cave springtail | Pseudosinella testa | Species of Concern | Wherever found | |
| Shelta Cave crayfish | Orconectes sheltae | Under Review | Wherever found | |
| Shelton pocket gopher | Thomomys mazama couchi | Resolved Taxon | Wherever found | |
| Shenandoah cave beetle | Pseudanophthalmus limicola | Resolved Taxon | Wherever found | |
| Shenandoah salamander | Plethodon shenandoah | Endangered | Wherever found | 08-18-1989 |
| Shenandoah Valley cave amphipod | Stygobromus gracilipes | Resolved Taxon | Wherever found | |
| Sherff railliardia | Dubautia sherffiana | Species of Concern | Wherever found | |
| Sherman's fox squirrel | Sciurus niger shermani | Species of Concern | Wherever found | |
| Sherman's southeastern pocket gopher | Geomys pinetis fontanelus | Resolved Taxon | Wherever found | |
| Shevock's milk-vetch | Astragalus shevockii | Resolved Taxon | Wherever found | |
| Shiner Perch | Cymatogaster aggregata | Not Listed | | |
| Shining milk-vetch | Astragalus lentiginosus micans | Resolved Taxon | Wherever found | |
| Shinner's false-foxglove | Tomanthera pseudaphylla | Species of Concern | Wherever found | |
| Shinner's sunflower | Helianthus occidentalis ssp. plantagineus | Status Undefined | | |
| Shinner's tickle-tongue | Zanthoxylum parvum | Resolved Taxon | Wherever found | |
| Shiny pigtoe | Fusconaia cor | Endangered | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Shiny pigtoe | Fusconaia cor | Experimental Population, Non-Essential | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Shiny pigtoe | Fusconaia cor | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Shinyrayed pocketbook | Hamiota subangulata | Endangered | Wherever found | 03-16-1998 |
| Ship Sturgeon | Acipenser nudiventris | Proposed Endangered | Wherever found | |
| Shirley Meadows mariposa lily | Calochortus westonii | Species of Concern | Wherever found | |
| Shirttail Creek stonefly | Megaleuctra sierra | Species of Concern | Wherever found | |
| Shivwits milk-vetch | Astragalus ampullarioides | Endangered | Wherever found | 09-28-2001 |
| Shoal Bass | Micropterus cataractae | Not Listed | | |
| Shoal Chub | Macrhybopsis hyostoma | Not Listed | | |
| Shoal Chub | Macrhybopsis hyostoma | Not Listed | | |
| Shoal sprite | Amphigyra alabamensis | Species of Concern | Wherever found | |
| Shoals spider-lily | Hymenocallis coronaria | Species of Concern | Wherever found | |
| Shockley's rock-cress | Arabis shockleyi | Resolved Taxon | Wherever found | |
| Short-billed Dowitcher | Limnodromus griseus | Species of Concern | Wherever found | |
| Short-eared Owl | Asio flammeus | Species of Concern | Wherever found | |
| Short-eared Owl | Asio flammeus flammeus | Species of Concern | | |
| Shortface lanx | Fisherola nuttalli | Resolved Taxon | Wherever found | |
| Short-foot ectemnius sphecid wasp | Ectemnius curtipes | Species of Concern | Wherever found | |
| Short-fruited spikerush | Eleocharis brachycarpa | Resolved Taxon | Wherever found | |
| Short-headed garter snake | Thamnophis brachystoma | Species of Concern | Wherever found | |
| Shorthead Redhorse | Moxostoma macrolepidotum | Not Listed | | |
| Shorthead Sculpin | Cottus confusus | Not Listed | | |
| Shortjaw cisco | Coregonus zenithicus | Species of Concern | Wherever found | |
| Short-jointed beavertail cactus | Opuntia basilaris brachyclada | Species of Concern | Wherever found | |
| Short-leaved dudleya | Dudleya blochmaniae blochmaniae | Species of Concern | Wherever found | |
| Short-leaved dudleya | Dudleya blochmaniae brevifolia | Resolved Taxon | Wherever found | |
| Short-leaved rosemary | Conradina brevifolia | Endangered | | 07-12-1993 |
| Short-lobed broomrape | Orobanche parishii brachyloba | Species of Concern | Wherever found | |
| Short-lobed paintbrush | Castilleja brevilobata | Resolved Taxon | Wherever found | |
| Short-necked or western swamp turtle | Pseudemydura umbrina | Endangered | Wherever found | 06-02-1970 |
| Shortneck snaggletooth | Gastrocopta dalliana dalliana | Species of Concern | Wherever found | |
| Shortnose cisco | Coregonus reighardi | Species of Concern | Wherever found | |
| Short-nosed kangaroo rat | Dipodomys nitratoides brevinasus | Species of Concern | Wherever found | |
| Shortnose Gar | Lepisosteus platostomus | Not Listed | | |
| Shortnose sturgeon | Acipenser brevirostrum | Endangered | Wherever found | 03-11-1967 |
| Shortnose Sucker | Chasmistes brevirostris | Endangered | Wherever found | 07-18-1988 |
| Short-podded thelypody | Thelypodium brachycarpum | Resolved Taxon | Wherever found | |
| Shortridge's mouse | Pseudomys shortridgei | Endangered | Wherever found | 12-02-1970 |
| Short Samoan tree snail | Somoana abbreviata | Species of Concern | Wherever found | |
| Short's bladderpod | Physaria globosa | Endangered | Wherever found | 08-01-2014 |
| Short's goldenrod | Solidago shortii | Endangered | Wherever found | 09-05-1985 |
| Short-spire elimia | Elimia brevis | Resolved Taxon | Wherever found | |
| Shortspire hornsnail | Pleurocera curta | Not Listed | Wherever found | |
| Short-tailed albatross | Phoebastria (=Diomedea) albatrus | Endangered | Wherever found | 06-02-1970 |
| short-tailed chinchilla | Chinchilla chinchilla | Not Listed | | |
| short-tailed hawk | Buteo brachyurus | Species of Concern | Wherever found | |
| short-tailed hawk | Buteo brachyurus | Status Undefined | Florida population | |
| Short-tailed snake | Stilosoma extenuatum | Proposed Threatened | Wherever found | |
| Shoshone pupfish | Cyprinodon nevadensis shoshone | Species of Concern | Wherever found | |
| Shoshone sculpin | Cottus greenei | Resolved Taxon | Wherever found | |
| Shou | Cervus elaphus wallichi | Endangered | Wherever found | 06-02-1970 |
| Shovelnose Sturgeon | Scaphirhynchus platorynchus | Similarity of Appearance (Threatened) | Wherever found | 10-01-2010 |
| Showy Indian clover | Trifolium amoenum | Endangered | Wherever found | 10-22-1997 |
| Showy madia | madia radiata | Species of Concern | Wherever found | |
| Showy raillardella | Raillardella pringlei | Species of Concern | Wherever found | |
| Showy stickseed | Hackelia venusta | Endangered | Wherever found | 02-06-2002 |
| Shriver's Purple Fringed Orchid | Platanthera shriveri | Species of Concern | | |
| Shrubby reed-mustard | Schoenocrambe suffrutescens | Endangered | Wherever found | 10-06-1987 |
| Shutispear crayfish | Procambarus lylei | Status Undefined | Wherever found | |
| Siamang | Symphalangus syndactylus | Endangered | Wherever found | 06-14-1976 |
| Siamese crocodile | Crocodylus siamensis | Endangered | Wherever found | 06-14-1976 |
| Siberian sturgeon | Acipenser baerii | Under Review | Wherever found | |
| Siberian white Crane | Grus leucogeranus | Endangered | Wherever found | 12-02-1970 |
| Sichuan snub-nosed monkey | Rhinopithecus roxellana | Endangered | Wherever found | 09-27-1990 |
| Sickle darter | Percina williamsi | Threatened | Wherever found | 12-07-2022 |
| Sicklefin chub | Macrhybopsis meeki | Resolved Taxon | Wherever found | |
| Sicklefin redhorse | Moxostoma sp. | Not Listed | Wherever found | |
| Sidelong supercoil | Paravitrea ceres | Species of Concern | Wherever found | |
| sidewinder | Crotalus cerastes | Species of Concern | Wherever found | |
| Sierra Ancha Talussnail | Sonorella anchana | Resolved Taxon | Wherever found | |
| Sierra Blanca Woodlandsnail | Ashmunella rhyssa | Resolved Taxon | Wherever found | |
| Sierra corydalis | Corydalis caseana caseana | Resolved Taxon | Wherever found | |
| Sierra Nevada bighorn sheep | Ovis canadensis sierrae | Endangered | U.S.A. (CA) Sierra Nevada | 04-20-1999 |
| Sierra Nevada bleeding-heart | Dicentra nevadensis | Resolved Taxon | Wherever found | |
| Sierra Nevada red fox | Vulpes vulpes necator | Endangered | Sierra Nevada DPS | 09-02-2021 |
| Sierra Nevada red fox | Vulpes vulpes necator | Resolved Taxon | Southern Cascades DPS | |
| Sierra Nevada red fox | Vulpes vulpes necator | Resolved Taxon | Wherever found | |
| Sierra Nevada red fox | Vulpes vulpes ssp. necator | Status Undefined | Wherever found | |
| Sierra Nevada snowshoe hare | Lepus americanus tahoensis | Species of Concern | Wherever found | |
| Sierra Nevada Yellow-legged Frog | Rana sierrae | Endangered | Wherever found | 06-30-2014 |
| Sierra night lizard | Xantusia vigilis sierrae | Species of Concern | Wherever found | |
| Sierra pygmy grasshopper | Tetrix sierrana | Species of Concern | Wherever found | |
| Sierra sedge | Carex mariposana | Resolved Taxon | Wherever found | |
| Sierra sweet-bay | Myrica hartwegii | Resolved Taxon | Wherever found | |
| Sierra Valley evening-primrose | Camissonia tanacetifolia quadriperforata | Resolved Taxon | Wherever found | |
| Sierra Valley ivesia | Ivesia aperta aperta | Species of Concern | Wherever found | |
| Sierra Vieja brickellia | Brickellia viejensis | Species of Concern | Wherever found | |
| Sifakas | Propithecus spp. | Endangered | Wherever found | 12-02-1970 |
| signal crayfish | Pacifastacus leniusculus | Not Listed | | |
| Siler pincushion cactus | Pediocactus (=Echinocactus,=Utahia) sileri | Threatened | Wherever found | 11-26-1979 |
| Siler's Fishhook Cactus | Sclerocactus sileri | Resolved Taxon | Wherever found | |
| Silken cave beetle | Pseudanophthalmus sericus | Resolved Taxon | Wherever found | |
| Silky cryptantha | Cryptantha crinita | Species of Concern | Wherever found | |
| Silky pocket mouse | Perognathus flavus goodpasteri | Species of Concern | Wherever found | |
| Silt elimia | Elimia haysiana | Species of Concern | Wherever found | |
| Silverband Shiner | Notropis shumardi | Not Listed | | |
| Silver cholla | Opuntia imbricata argentea | Species of Concern | Wherever found | |
| Silver Chub | Macrhybopsis storeriana | Not Listed | | |
| Silver Creek blind harvestman | Calicina jungi | Resolved Taxon | Wherever found | |
| Silver Creek Holospira | Holospira sherbrookei | Resolved Taxon | Wherever found | |
| Silver Creek Woodlandsnail | Ashmunella binneyi | Resolved Taxon | Wherever found | |
| Silver Glen Springs crayfish | Procambarus attiguus | Under Review | Wherever found | |
| Silver-haired bat | lasionycteris noctivagans | Species of Concern | Wherever found | |
| Silver-haired ivesia | Ivesia argyrocoma | Species of Concern | Wherever found | |
| Silverling | Paronychia argyrocoma | Resolved Taxon | Wherever found | |
| Silver Redhorse | Moxostoma anisurum | Not Listed | | |
| Silver rice rat | Oryzomys palustris natator | Endangered | Lower FL Keys (west of Seven Mile Bridge) | 04-30-1991 |
| Silver, San Clemente Island hosackia | Lotus argophyllus adsurgens | Resolved Taxon | Wherever found | |
| Silver, Santa Cruz Island hosackia | Lotus argophyllus niveus | Species of Concern | Wherever found | |
| Silverspot | Speyeria nokomis nokomis | Threatened | Wherever found | 03-18-2024 |
| Silver trout | Salvelinus agassizii | Resolved Taxon | Wherever found | |
| Silver wolfberry | Lycium puberulum berberioides | Resolved Taxon | Wherever found | |
| Silvery legless lizard | Anniella pulchra pulchra | Species of Concern | Wherever found | |
| Silvery nailwort | Paronychia virginica var. virginica | Species of Concern | Wherever found | |
| Simien fox | Canis simensis | Endangered | Wherever found | 07-27-1979 |
| Simple Amphipod | Stygobromus simplex | Resolved Taxon | Wherever found | |
| Simple hydroporus diving beetle | Hydroporus simplex | Species of Concern | Wherever found | |
| Simple-necked long-horned beetle | Plagithmysus simplicicollis | Species of Concern | Wherever found | |
| Simple rhyncogonus weevil | Rhyncogonus simplex | Species of Concern | Wherever found | |
| Simple yellow-faced bee | Hylaeus simplex | Species of Concern | Wherever found | |
| Simpson's prickly-apple | Cereus gracilis simpsonii | Species of Concern | Wherever found | |
| Simpson stopper | Myrcianthes fragrans simpsonii | Species of Concern | Wherever found | |
| Sinaloan jaguarundi | Puma yagouaroundi tolteca | Endangered | Wherever found | 06-14-1976 |
| Singapore roundleaf horseshoe bat | Hipposideros ridleyi | Endangered | Wherever found | 01-23-1984 |
| Sira curassow | Pauxi koepckeae | Endangered | | 08-26-2024 |
| Sirajo Goby | Sicydium plumieri | Not Listed | | |
| Siskiyou buckwheat | Eriogonum siskiyouense | Resolved Taxon | Wherever found | |
| Siskiyou caddisfly | Neothremma siskiyou | Species of Concern | Wherever found | |
| Siskiyou caddisfly | Tinodes siskiyou | Species of Concern | Wherever found | |
| Siskiyou chloealtis grasshopper | Chloealtis aspasma | Species of Concern | Wherever found | |
| Siskiyou ground beetle | Nebria gebleri siskiyouensis | Species of Concern | Wherever found | |
| Siskiyou inside-out flower | Vancouveria chrysantha | Resolved Taxon | Wherever found | |
| Siskiyou Mariposa lily | Calochortus persistens | Resolved Taxon | Wherever found | |
| Siskiyou monardella | Monardella purpurea | Resolved Taxon | Wherever found | |
| Siskiyou Mountains bilberry | Vaccinium membranaceum | Resolved Taxon | Wherever found | |
| Siskiyou Mountains salamander | Plethodon stormi | Resolved Taxon | Wherever found | |
| Siskiyou onion | Allium tribracteatum | Species of Concern | Wherever found | |
| Siskiyou paintbrush | Castilleja elata | Resolved Taxon | Wherever found | |
| Siskiyou rock-fringe | Epilobium siskiyouense | Resolved Taxon | Wherever found | |
| Siskiyou sideband | Monadenia chaceana | Resolved Taxon | Wherever found | |
| Siuslaw hairy-necked tiger beetle | Cicindela hirticollis siuslawensis | Under Review | | |
| Sixbanded long-horned beetle | Dryobius sexnotatus | Species of Concern | Wherever found | |
| Skiff milkvetch | Astragalus microcymbus | Resolved Taxon | Wherever found | |
| Skipjack Herring | Alosa chrysochloris | Not Listed | | |
| Skirted hornsnail | Pleurocera pyrenella | Status Undefined | Wherever found | |
| Skull Valley pocket gopher | Thomomys umbrinus robustus | Species of Concern | Wherever found | |
| Slabside Pearlymussel | Pleuronaia dolabelloides | Endangered | Wherever found | 10-28-2013 |
| Slackwater darter | Etheostoma boschungi | Threatened | Wherever found | 10-11-1977 |
| Sleeping Ute milkvetch | Astragalus tortipes | Resolved Taxon | Wherever found | |
| Slender-billed curlew | Numenius tenuirostris | Endangered | Wherever found | 09-12-2011 |
| Slender-billed Grackle | Quisicalus palustris | Endangered | Wherever found | 06-02-1970 |
| Slender campeloma | Campeloma decampi | Endangered | Wherever found | 02-25-2000 |
| Slender chub | Erimystax cahni | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.84(s)(1)(i)) | 10-15-2007 |
| Slender chub | Erimystax cahni | Threatened | Wherever found | 10-11-1977 |
| Slenderclaw crayfish | Cambarus cracens | Endangered | Wherever found | 10-08-2021 |
| Slender dodder | Cuscuta attenuata | Species of Concern | Wherever found | |
| Slender gay-feather | Liatris tenuis | Species of Concern | Wherever found | |
| Slenderhead Darter | Percina phoxocephala | Not Listed | | |
| Slender-horned gazelle | Gazella leptoceros | Endangered | Wherever found | 06-02-1970 |
| Slender-horned spineflower | Dodecahema leptoceras | Endangered | Wherever found | 09-28-1987 |
| Slender mariposa lily | Calochortus clavatus gracilis | Species of Concern | Wherever found | |
| slender meadowfoam | Limnanthes gracilis ssp. gracilis | Species of Concern | Wherever found | |
| Slender meadowfoam | Lasthenia macrantha prisca | Species of Concern | Wherever found | |
| Slender Moonwort | Botrychium lineare | Resolved Taxon | Wherever found | |
| Slender oak | Quercus graciliformis | Resolved Taxon | Wherever found | |
| Slender Orcutt grass | Orcuttia tenuis | Threatened | Wherever found | 03-26-1997 |
| Slender pentachaeta | Pentachaeta exilis aeolica | Species of Concern | Wherever found | |
| Slender-petaled mustard | Thelypodium stenopetalum | Endangered | Wherever found | 08-31-1984 |
| Slender-pod jewelflower | Caulanthus heterophyllus | Resolved Taxon | Wherever found | |
| Slender rush-pea | Hoffmannseggia tenella | Endangered | Wherever found | 11-01-1985 |
| Slender sculpin | Cottus tenuis | Species of Concern | Wherever found | |
| Slender spiderflower | Cleome multicaulis | Species of Concern | Wherever found | |
| Slenderwrist burrowing crayfish | Fallicambarus petilicarpus | Under Review | Wherever found | |
| Slevin's skink | Emoia slevini | Endangered | Wherever found | 11-02-2015 |
| Slickrock desert-parsley | Lomatium latilobum | Resolved Taxon | Wherever found | |
| Slickspot peppergrass | Lepidium papilliferum | Threatened | | 09-16-2016 |
| Slimy Sculpin | Cottus cognatus | Not Listed | | |
| Slippershell Mussel | Pressodonta viridis | Not Listed | | |
| Slough Darter | Etheostoma gracile | Not Listed | | |
| Slough thistle | Cirsium crassicaule | Species of Concern | Wherever found | |
| Slow rhyncogonus weevil | Rhyncogonus segnis segnis | Species of Concern | Wherever found | |
| Slowwater elimia | Elimia interveniens | Species of Concern | Wherever found | |
| Small-anthered bittercress | Cardamine micranthera | Endangered | Wherever found | 09-21-1989 |
| Small beardtongue | Penstemon parvus | Species of Concern | Wherever found | |
| Smalleye Shiner | Notropis buccula | Endangered | Wherever found | 08-04-2014 |
| Small-flowered, Douglas' pogogyne | Pogogyne douglasii parviflora | Resolved Taxon | Wherever found | |
| Small-flowered microseris | microseris douglasii ssp. platycarpha | Species of Concern | Wherever found | |
| Small-flowered morning-glory | Convolvulus equitans | Species of Concern | Wherever found | |
| Small fryxell wort | Fryxellia pygmaea | Resolved Taxon | Wherever found | |
| Small geniculate river snail | Lithasia pinguis | Resolved Taxon | Wherever found | |
| Small-headed goldenweed | Lorandersonia microcephala | Species of Concern | Wherever found | |
| Small-headed pipewort | Eriocaulon kornickianum | Under Review | Wherever found | |
| Smallheaded Townsend Daisy | Townsendia microcephala | Resolved Taxon | Wherever found | |
| Small-leaved agastache | Agastache parvifolia | Resolved Taxon | Wherever found | |
| Small-leaved nehe | Lipochaeta degeneri | Species of Concern | Wherever found | |
| Small-leaved rose | Rosa minutifolia | Species of Concern | Wherever found | |
| Small-living, thick-nerved sedge | Carex microptera crassinervia | Resolved Taxon | Wherever found | |
| Smallmouth bass | Micropterus dolomieu | Status Undefined | Wherever found | |
| Smallmouth Buffalo | Ictiobus bubalus | Not Listed | | |
| Small papillosus | Echinocereus papillosus angusticeps | Species of Concern | Wherever found | |
| Smallscale darter | Etheostoma microlepidum | Resolved Taxon | Wherever found | |
| Small Shasta lily | Lilium washingtonianum minus | Resolved Taxon | Wherever found | |
| Small's milkpea | Galactia smallii | Endangered | | 07-18-1985 |
| Small's Rainlily | Cooperia smallii | Resolved Taxon | Wherever found | |
| Small's southern clarkia | Clarkia australis | Resolved Taxon | Wherever found | |
| Smalltooth sawfish | Pristis pectinata | Endangered | Non-US DPS - Smalltooth sawfish originating from non-US waters | 01-12-2015 |
| Smalltooth sawfish | Pristis pectinata | Endangered | US DPS - Smalltooth sawfish originating from U.S. waters. | 11-16-2005 |
| Small white lady's-slipper | Cypripedium candidum | Resolved Taxon | Wherever found | |
| Small whorled pogonia | Isotria medeoloides | Threatened | | 09-09-1982 |
| Smith's blue butterfly | Euphilotes enoptes smithi | Endangered | Wherever found | 06-08-1976 |
| Smiths Island cottontail rabbit | Sylvilagus floridanus hitchensi | Species of Concern | Wherever found | |
| Smith's Longspur | Calcarius pictus | Species of Concern | Wherever found | |
| Smith's siacellan reduviid | Saicella smithi | Species of Concern | Wherever found | |
| Smith wild-buckwheat | Eriogonum smithii | Resolved Taxon | Wherever found | |
| Smokies needlefly | Megaleuctra williamsae | Under Review | Wherever found | |
| Smokies snowfly | Allocapnia fumosa | Status Undefined | Wherever found | |
| Smoky eyed brown butterfly | Satyrodes eurydice fumosa | Resolved Taxon | Wherever found | |
| Smoky madtom | Noturus baileyi | Endangered | Wherever found | 10-26-1984 |
| Smoky madtom | Noturus baileyi | Experimental Population, Non-Essential | The Tellico River, between the backwaters of the Tellico Reservoir (approximately Tellico River mile 19 (30.4 kilometers) and Tellico River mile 33 (52.8 kilometers), near the Tellico Ranger Station, Monroe County, Tennessee. | 08-12-2002 |
| Smoky Mountains manna grass | Glyceria nubigena | Species of Concern | Wherever found | |
| Smoky mouse | Pseudomys fumeus | Endangered | Wherever found | 12-02-1970 |
| Smoothback angelshark | Squatina oculata | Endangered | | 08-31-2016 |
| Smooth barked St. JohnÂ’s wort | Hypericum lissophloeus | Under Review | Wherever found | |
| Smooth-billed ani | Crotophaga ani | Resolved Taxon | Wherever found | |
| Smooth blue-star | Amsonia glaberrima | Resolved Taxon | Wherever found | |
| Smooth bog-asphodel | Tofieldia glabra | Species of Concern | Wherever found | |
| Smooth catseye | Cryptantha semiglabra | Under Review | Wherever found | |
| Smooth coneflower | Echinacea laevigata | Threatened | Wherever found | 10-08-1992 |
| Smooth Glenwood Pyrg | Pyrgulopsis chamberlini | Resolved Taxon | Wherever found | |
| Smooth-leaf bluebells | Mertensia viridis dilatata | Resolved Taxon | Wherever found | |
| smooth lessingia | Lessingia micradenia var. glabrata | Species of Concern | Wherever found | |
| Smooth pimpleback | Cyclonaias houstonensis | Resolved Taxon | Wherever found | |
| Smooth pungent forsellesia | Glossopetalon pungens glabra | Species of Concern | Wherever found | |
| Smooth rocksnail | Leptoxis virgata | Status Undefined | Wherever found | |
| Smooth Softshell Turtle | Apalone mutica | Not Listed | | |
| Smooth-stem skullcap | Scutellaria laevis | Resolved Taxon | Wherever found | |
| Smooth stickleaf | Mentzelia mollis | Resolved Taxon | Wherever found | |
| Smooth tarplant | Hemizonia pungens laevis | Species of Concern | Wherever found | |
| Smyrna seaside sparrow | Ammodramus maritimus pelonotus | Resolved Taxon | Wherever found | |
| Smyth's apamea moth | Apamea smythi | Species of Concern | Wherever found | |
| Smyth's tiger beetle | Cicindela chlorocephala smythi | Species of Concern | Wherever found | |
| Snail Bullhead | Ameiurus brunneus | Not Listed | | |
| Snail darter | Percina tanasi | Recovery | Wherever found | 11-10-1975 |
| Snail [no common name] | Eua zebrina | Endangered | Wherever found | 10-24-2016 |
| Snail [no common name] | Ostodes strigatus | Endangered | Wherever found | 10-24-2016 |
| Snail shell cave beetle | Pseudanophthalmus acherontis | Resolved Taxon | Wherever found | |
| Snake cholla | Opuntia parryi serpentina | Species of Concern | Wherever found | |
| Snake River physa snail | Physella natricina | Endangered | Wherever found | 12-14-1992 |
| Snake River sucker | Chasmistes muriei | Resolved Taxon | Wherever found | |
| Snakeroot | Eryngium cuneifolium | Endangered | | 01-21-1987 |
| Snapping Turtle | Chelydra serpentine | Not Listed | | |
| snares crested penguin | Eudyptes robustus | Resolved Taxon | Wherever found | |
| Sneed pincushion cactus | Coryphantha sneedii var. sneedii | Endangered | Wherever found | 12-07-1979 |
| Snow leopard | Uncia (=Panthera) uncia | Endangered | Wherever found | 03-28-1972 |
| Snow, little draba | Draba nivalis brevicula | Resolved Taxon | Wherever found | |
| Snow Mountain buckwheat | Eriogonum nervulosum | Species of Concern | Wherever found | |
| Snow Mountain willowherb | Epilobium nivium | Resolved Taxon | Wherever found | |
| Snowy Egret | Egretta thula | Species of Concern | Wherever found | |
| Snowy Owl | Bubo scandiacus | Species of Concern | | |
| Snowy Plover | Charadrius alexandrinus | Species of Concern | Wherever found | |
| Snowy Plover | Charadrius nivosus tenuirostris | Species of Concern | | |
| Snowy yellow-faced bee | Nesoprosopis nivalis | Resolved Taxon | Wherever found | |
| Snuffbox mussel | Epioblasma triquetra | Endangered | Wherever found | 03-15-2012 |
| Sockeye salmon | Oncorhynchus (=Salmo) nerka | Endangered | Snake River ESU - See 50 CFR 224.101 | 01-03-1992 |
| Sockeye salmon | Oncorhynchus (=Salmo) nerka | Resolved Taxon | Lake Sammamish and Lake Washington | |
| Sockeye salmon | Oncorhynchus (=Salmo) nerka | Status Undefined | Kokanee, landlocked, wherever found. | |
| Sockeye salmon | Oncorhynchus (=Salmo) nerka | Threatened | Ozette Lake ESU - See 50 CFR 223.102 | 03-25-1999 |
| Sockeye Salmon | Oncorhynchus nerka | Not Listed | | |
| Socorro isopod | Thermosphaeroma thermophilus | Endangered | Wherever found | 04-26-1978 |
| Socorro mockingbird | Mimus graysoni | Endangered | Wherever found | 01-16-2008 |
| Socorro springsnail | Pyrgulopsis neomexicana | Endangered | Wherever found | 09-30-1991 |
| Sodaville milk-vetch | Astragalus lentiginosus sesquimetralis | Resolved Taxon | Wherever found | |
| Soft bird's-beak | Cordylanthus mollis ssp. mollis | Endangered | Wherever found | 11-20-1997 |
| Soft-leaved paintbrush | Castilleja mollis | Endangered | Wherever found | 07-31-1997 |
| Solano grass | Tuctoria mucronata | Endangered | Wherever found | 09-29-1978 |
| Soldier Meadows Cinquefoil | Potentilla basaltica | Resolved Taxon | Wherever found | |
| Solitary Sandpiper | Tringa solitaria | Species of Concern | Wherever found | |
| Solitary Sandpiper | Tringa solitaria cinnamomea | Species of Concern | | |
| Solitary tinamou | Tinamus solitarius | Endangered | Wherever found | 06-14-1976 |
| Song Sparrow | Melospiza melodia | Species of Concern | Wherever found | |
| Song Sparrow | Melospiza melodia maxillaris | Species of Concern | Wherever found | |
| Song Sparrow | Melospiza melodia pusillula | Species of Concern | Wherever found | |
| Song Sparrow | Melospiza melodia samuelis | Species of Concern | Wherever found | |
| Sonoma alopecurus | Alopecurus aequalis var. sonomensis | Endangered | Wherever found | 10-22-1997 |
| Sonoma arctic skipper | Carterocephalus palaemon ssp. | Species of Concern | Wherever found | |
| Sonoma ceanothus | Ceanothus sonomensis | Species of Concern | Wherever found | |
| Sonoma spineflower | Chorizanthe valida | Endangered | Wherever found | 06-22-1992 |
| Sonoma sunshine | Blennosperma bakeri | Endangered | Wherever found | 12-02-1991 |
| Sonora chub | Gila ditaenia | Threatened | Wherever found | 04-30-1986 |
| Sonora fleabane | Erigeron versicolor | Species of Concern | Wherever found | |
| Sonoran desert tortoise | Gopherus morafkai | Resolved Taxon | Wherever found | |
| Sonoran green toad | Bufo retiformis | Resolved Taxon | Wherever found | |
| Sonoran lyre snake | trimorphodon biscutatus ssp. lambda | Species of Concern | Wherever found | |
| Sonoran panic grass | Panicum sonoran | Status Undefined | Wherever found | |
| Sonoran pronghorn | Antilocapra americana sonoriensis | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Sonoran pronghorn | Antilocapra americana sonoriensis | Experimental Population, Non-Essential | In Arizona, an area north of Interstate 8 and south of Interstate 10, bounded by the Colorado River on the west and Interstate 10 on the east; and an area south of Interstate 8, bounded by Highway 85 on the west, Interstates 10 and 19 on the east, and the U.S.-Mexico border on the south | 05-05-2011 |
| Sonoran Snaggletooth | Gastrocopta prototypus | Resolved Taxon | Wherever found | |
| Sonoran talussnail | Sonorella magdalenensis | Under Review | Wherever found | |
| Sonoran tiger salamander | Ambystoma mavortium stebbinsi | Endangered | Wherever found | 01-06-1997 |
| Sonoran Yellow Warbler | Dendroica petechia ssp. sonorana | Species of Concern | Wherever found | |
| Sonora sucker | Catostomus insignis | Species of Concern | Wherever found | |
| Sonoyta mud turtle | Kinosternon sonoriense longifemorale | Endangered | Wherever found | 10-20-2017 |
| Sooty Shearwater | Ardenna grisea | Species of Concern | Wherever found | |
| Sooty Tern | Onychoprion fuscatus | Species of Concern | | |
| Soror odynerus vespid wasp | Odynerus soror | Species of Concern | Wherever found | |
| South American (=Brazilian) tapir | Tapirus terrestris | Endangered | Wherever found | 06-02-1970 |
| South American red-lined turtle | Trachemys scripta callirostris | Endangered | Wherever found | 09-30-1991 |
| South Andean huemul | Hippocamelus bisulcus | Endangered | Wherever found | 06-14-1976 |
| South Asian River dolphin | Platanista gangetica minor | Endangered | Wherever found | 01-14-1991 |
| South Branch Valley cave beetle | Pseudanophthalmus potomaca potomaca | Not Listed | Wherever found | |
| South China sika deer | Cervus nippon kopschi | Endangered | Wherever found | 07-27-1979 |
| South coast garter snake | Thamnophis sirtalis ssp. | Species of Concern | Wherever found | |
| South Coast Range morning-glory | Calystegia collina venusta | Species of Concern | Wherever found | |
| South coast saltbush | Atriplex pacifica | Species of Concern | Wherever found | |
| Southeastern American Kestrel | Falco sparverius paulus | Species of Concern | Wherever found | |
| Southeastern beach mouse | Peromyscus polionotus niveiventris | Threatened | wherever found | 05-12-1989 |
| Southeastern myotis | Myotis austroriparius | Species of Concern | Wherever found | |
| Southeastern rufous-vented ground cuckoo | Neomorphus geoffroyi dulcis | Endangered | Wherever found | 01-27-2011 |
| Southeastern walleye | Stizostedion vitreum vitreum | Resolved Taxon | Mobile River Drainage | |
| Southern acornshell | Epioblasma othcaloogensis | Extinction | Wherever found | 03-17-1993 |
| Southern Appalachian black-capped chickadee | Poecile atricapillus ssp. practica | Species of Concern | Wherever found | |
| Southern Appalachian eastern woodrat | Neotoma floridana haematoreia | Species of Concern | Wherever found | |
| Southern bearded saki | Chiropotes satanas satanas | Endangered | Wherever found | 05-16-1986 |
| Southern Brook Lamprey | Ichthyomyzon gagei | Not Listed | | |
| Southern California rufous-crowned sparrow | Aimophila ruficeps canescens | Species of Concern | Wherever found | |
| Southern cave crayfish | orconectes australis ssp. australis | Species of Concern | Wherever found | |
| Southern cavefish | typhlichthys subterraneus | Species of Concern | Wherever found | |
| Southern clubshell | Pleurobema decisum | Endangered | Wherever found | 03-17-1993 |
| Southern combshell | Epioblasma penita | Endangered | Wherever found | 04-07-1987 |
| Southern Duckwater pyrg | Pyrgulopsis anatina | Resolved Taxon | Wherever found | |
| Southern Dusky Salamander | Desmognathus auriculatus | Resolved Taxon | Wherever found | |
| Southern elktoe | Alasmidonta triangulata | Proposed Endangered | Wherever found | |
| Southern Fatmucket | Lampsilis straminea | Not Listed | | |
| Southern Flounder | Paralichthys lethostigma | Not Listed | | |
| Southern grasshopper mouse | Onychomys torridus ramona | Species of Concern | Wherever found | |
| Southern-helmeted curassow | Pauxi unicornis | Endangered | Wherever found | 08-26-2024 |
| Southern hickorynut | Obovaria jacksoniana | Resolved Taxon | Wherever found | |
| Southern hognose snake | Heterodon simus | Resolved Taxon | Wherever found | |
| Southern Idaho ground Squirrel | Urocitellus endemicus | Resolved Taxon | Wherever found | |
| Southern island phacelia | Phacelia floribunda | Species of Concern | Wherever found | |
| Southern kidneyshell | Ptychobranchus jonesi | Endangered | Wherever found | 10-10-2012 |
| Southern lance | Elliptio ahenea | Status Undefined | Wherever found | |
| Southern marsh harvest mouse | Reithrodontomys megalotis limicola | Resolved Taxon | Wherever found | |
| Southern meadowrue | Thalictrum debile | Status Undefined | | |
| Southern Mountain Caribou DPS | Rangifer tarandus ssp. caribou | Endangered | U.S.A. (wherever found), Canada (southeastern British Columbia) | 01-14-1983 |
| Southern mountain wild-buckwheat | Eriogonum kennedyi var. austromontanum | Threatened | Wherever found | 10-14-1998 |
| southern mule deer | Odocoileus hemionus spp. fuliginatus | Status Undefined | Wherever found | |
| Southern Oconee Bells | Shortia galacifolia var. galacifolia | Species of Concern | Wherever found | |
| Southern pig-tailed macaque | Macaca nemestrina | Not Listed | | |
| Southern pigtoe | Pleurobema georgianum | Endangered | Wherever found | 03-17-1993 |
| Southern Plains Bumblebee | Bombus fraternus | Under Review | | |
| Southern planigale | Planigale tenuirostris | Endangered | Wherever found | 12-02-1970 |
| Southern Pocketbook | Lampsilis ornata | Not Listed | | |
| Southern Purple Lilliput | Toxolasma corvunculus | Under Review | Wherever found | |
| Southern pygmy shrew | Sorex hoyi winnemana | Resolved Taxon | Wherever found | |
| Southern Racemose goldenrod | Solidago arenicola | Status Undefined | | |
| Southern Rainbow | Villosa vibex | Not Listed | | |
| Southern Redbelly Dace | Chrosomus erythrogaster | Not Listed | | |
| Southern rein-orchid | Platanthera flava | Resolved Taxon | Wherever found | |
| Southern Right Whale | Eubalaena australis | Endangered | Wherever found | 06-02-1970 |
| Southern river otter | Lontra (=Lutra) provocax | Endangered | Wherever found | 06-14-1976 |
| southern rockhopper penguin | Eudyptes chrysocome | Threatened | New Zealand-Australia DPS, associated with the Campbell Plateau and Macquarie Island | 03-24-2011 |
| Southern rock vole | Microtus chrotorrhinus carolinensis | Species of Concern | Wherever found | |
| Southern rubber boa | Charina bottae umbratica | Resolved Taxon | Wherever found | |
| Southern Ryukyu robin | Erithacus komadori subrufa | Resolved Taxon | Wherever found | |
| Southern sagebrush lizard | Sceloporus graciosus vandenburgianus | Resolved Taxon | Wherever found | |
| Southern Sandshell | Hamiota australis | Threatened | Wherever found | 10-10-2012 |
| Southern sea otter | Enhydra lutris nereis | Threatened | Wherever found | 01-14-1977 |
| Southern snaketail | Ophiogomphus australis | Under Review | Wherever found | |
| Southern Steptoe pyrg | Pyrgulopsis sulcata | Under Review | Wherever found | |
| Southern tarplant | Hemizonia parryi australis | Species of Concern | Wherever found | |
| Southern tawny crescent | Phyciodes batesii maconensis | Species of Concern | Wherever found | |
| Southern three-awned grass | Aristida simpliciflora | Species of Concern | Wherever found | |
| Southern Tightcoil | Ogaridiscus subrupicola | Resolved Taxon | Wherever found | |
| Southern torrent salamander | Rhyacotriton variegatus | Resolved Taxon | Wherever found | |
| Southern water shrew | Sorex palustris punctulatus | Species of Concern | Wherever found | |
| Southern white rhinoceros | Ceratotherium simum ssp. simum | Similarity of Appearance (Threatened) | Wherever found | 09-11-2013 |
| southern white-tailed ptarmigan | Lagopus leucura altipetens | Resolved Taxon | Wherever found | |
| Southern Yellow Bat | Dasypterus ega | Not Listed | | |
| Southern Yellow Bat | Lasiurus ega | Species of Concern | Wherever found | |
| South Florida rainbow snake | Farancia erytrogramma seminola | Resolved Taxon | Wherever found | |
| South Forks ground beetle | Nebria darlingtoni | Species of Concern | Wherever found | |
| South Island Hector's dolphin | Cephalorhynchus hectori hectori | Threatened | | 10-19-2017 |
| South Llano Springs moss | Donrichardsia macroneuron | Endangered | Wherever found | 05-30-2023 |
| South Mountain gray-cheeked salamander | Plethodon meridianus | Resolved Taxon | Wherever found | |
| South Polar Skua | Stercorarius maccormicki | Species of Concern | | |
| South Texas ambrosia | Ambrosia cheiranthifolia | Endangered | Wherever found | 08-24-1994 |
| Southwestern otter | Lutra canadensis sonora | Species of Concern | Wherever found | |
| Southwestern pond turtle | Actinemys pallida | Proposed Threatened | Wherever found | |
| Southwestern Virginia cave amphipod | Stygobromus mackini | Resolved Taxon | Wherever found | |
| Southwestern willow flycatcher | Empidonax traillii extimus | Endangered | Wherever found | 02-27-1995 |
| Southwest Nevada pyrg | Pyrgulopsis turbatrix | Resolved Taxon | Wherever found | |
| Southwest spring firefly | Bicellonycha wickershamorum | Under Review | | |
| Spalding's Catchfly | Silene spaldingii | Threatened | Wherever found | 10-10-2001 |
| Spangler's hydroporus diving beetle | Hydroporus spangleri | Species of Concern | Wherever found | |
| Spanish imperial eagle | Aquila heliaca adalberti | Endangered | Wherever found | 06-02-1970 |
| Spanish lynx | Felis pardina | Endangered | Wherever found | 06-02-1970 |
| Spanish Mackerel | Scomberomorus maculatus | Not Listed | | |
| Spanish needle onion | Allium shevockii | Species of Concern | Wherever found | |
| Sparrow pebblesnail | Somatogyrus parvulus | Species of Concern | Wherever found | |
| Spathulate seedbox | Ludwigia spathulata | Status Undefined | | |
| Speckled burrowing crayfish | Fallicambarus danielae | Under Review | Wherever found | |
| Speckled chub | Macrhybopsis aestivalis | Status Undefined | Wherever found | |
| Speckled dace | Rhinichthys osculus ssp. | Species of Concern | Gila & Bill Williams | |
| Speckled Dace | Rhinichthys osculus | Not Listed | | |
| Speckled Darter | Etheostoma stigmaeum | Not Listed | | |
| Speckled Madtom | Noturus leptacanthus | Not Listed | | |
| Speckled pocketbook | Lampsilis streckeri | Endangered | Wherever found | 02-28-1989 |
| Speckled rattlesnake | Crotalus mitchellii | Species of Concern | Wherever found | |
| Spectaclecase (mussel) | Cumberlandia monodonta | Endangered | Wherever found | 04-12-2012 |
| Spectacled eider | Somateria fischeri | Threatened | Wherever found | 05-10-1993 |
| Specular yellow-faced bee | Hylaeus specularis | Species of Concern | Wherever found | |
| Spellenberg's groundsel | Packera spellenbergii | Species of Concern | Wherever found | |
| (Speodesmus) millipede | speodesmus | Species of Concern | Wherever found | |
| Sperm whale | Physeter catodon (=macrocephalus) | Endangered | Wherever found | 06-02-1970 |
| (Sphalloplana mohri) flatworm | sphalloplana mohri | Species of Concern | Wherever found | |
| Sphecodoid yellow-faced bee | Hylaeus sphecodoides | Species of Concern | Wherever found | |
| Sphinx date palm | Phoenix dactylifera | Resolved Taxon | Wherever found | |
| Sphinx moth | Sphinx smithi | Resolved Taxon | Wherever found | |
| Spiculose serratellan mayfly | Serratella serrata | Species of Concern | Wherever found | |
| Spider Cave crayfish | Troglocambarus maclanei | Under Review | Wherever found | |
| Spider elimia | Elimia arachnoidea | Under Review | Wherever found | |
| Spider monkey | Ateles geoffroyi frontatus | Endangered | Wherever found | 06-02-1970 |
| Spider monkey | Ateles geoffroyl panamensis | Endangered | Wherever found | 06-02-1970 |
| Spider Tortoise | Pyxis arachnoides | Under Review | Wherever found | |
| Spike | Eurynia dilatata | Not Listed | | |
| Spikedace | Meda fulgida | Endangered | Wherever found | 07-01-1986 |
| Spindle elimia | Elimia capillaris | Species of Concern | Wherever found | |
| Spineless hedgehog Cactus | Echinocereus triglochidiatus var. inermis | Original Data in Error - Not a listable entity | | 12-07-1979 |
| Spiny angelshark | Squatina guggenheim | Endangered | | |
| Spinycheek Sleeper | Eleotris pisonis | Not Listed | | |
| Spiny Dogfish | Squalus acanthias | Not Listed | | |
| Spiny Florida sandhill scarab | Gronocarus multispinosus | Species of Concern | Wherever found | |
| Spiny rhyacophilan caddisfly | Rhyacophila spinata | Species of Concern | Wherever found | |
| Spiny riversnail | Io fluvialis | Under Review | Wherever found | |
| Spiny Scale crayfish | Cambarus jezerinaci | Under Review | Wherever found | |
| Spinysepaled eryngo | Eryngium spinosepalum | Species of Concern | Wherever found | |
| Spiny Softshell Turtle | Apalone spinifera | Not Listed | | |
| Spinytail crayfish | Procambarus fitzpatricki | Resolved Taxon | Wherever found | |
| Spiral hornsnail | Pleurocera brumbyi | Species of Concern | Wherever found | |
| Splendid Darter | Etheostoma barrenense | Not Listed | | |
| Splendid shield-backed katydid | Ateloplus splendidus | Resolved Taxon | Wherever found | |
| Splitting yarn lichen | Sulcaria isidiisera | Species of Concern | Wherever found | |
| Sp. nov. ined. (Appalachian) oak fern | Gymnocarpium sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. artemisia | Artemisia | Resolved Taxon | Wherever found | |
| Sp. nov. ined. blue curls | Trichostema sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. browallia | Browallia sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. (chaparral) beargrass | Nolina sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. cirsium | Cirsium sp. | Species of Concern | R6 | |
| Sp. nov. ined. (Del Norte) rock-cress | Arabis sp. | Species of Concern | Del Norte | |
| Sp. nov. ined. erigeron | Erigeron sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. (Gray Knolls) rock-cress | Arabis sp. | Resolved Taxon | Gray Knolls | |
| Sp. nov. ined. (gypsum) townsendia | Townsendia sp. | Species of Concern | NM | |
| Sp. nov. ined. leptodactylon | Leptodactylon sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. lysimachia | Lysimachia sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. (munchkin) dudleya | Dudleya sp. | Resolved Taxon | Wherever found | |
| Sp. nov. ined. (Nye Co.) townsendia | Townsendia sp. | Resolved Taxon | Nye Co. | |
| Sp. nov. ined. (Pit River) jewelflower | Streptanthus sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. sclerocactus | Sclerocactus sp. | Resolved Taxon | Wherever found | |
| Sp. nov. ined. (Tonto Basin) agave | Agave sp. | Species of Concern | Wherever found | |
| Sp. nov. ined. (Waihoi Valley) lysimachia | Lysimachia sp. nov. ined. | Resolved Taxon | Waihoi Valley | |
| Sp. nov. ined. (WY) townsendia | Townsendia sp. | Species of Concern | WY | |
| Spongy sponge | Spongilla sponginosa | Resolved Taxon | Wherever found | |
| Spoonhead Sculpin | Cottus ricei | Not Listed | | |
| Sportinggoods tryonia | Tryonia angulata | Resolved Taxon | Wherever found | |
| Spot | Leiostomus xanthurus | Not Listed | | |
| Spotfin Chub | Erimonax monachus | Experimental Population, Non-Essential | U.S.A. (AL, TN-specified portions of Shoal Creek; see 17.84(m)(1)(ii)) | 04-08-2005 |
| Spotfin Chub | Erimonax monachus | Experimental Population, Non-Essential | U.S.A. (TN-specified portions of the French Broad and Holston Rivers; see 17.84(m)(1)(iii)) | 10-15-2007 |
| Spotfin Chub | Erimonax monachus | Experimental Population, Non-Essential | U.S.A. (TN-specified portions of the Tellico River; see 17.84(m)(1)(i)) | 08-12-2002 |
| Spotfin Chub | Erimonax monachus | Threatened | Wherever found, except where listed as an experimental population | 10-11-1977 |
| Spotfin Gambusia | Gambusia krumholzi | Not Listed | | |
| Spotfin Shiner | Cyprinella spiloptera | Not Listed | | |
| Spotless Crake | Porzana tabuensis | Resolved Taxon | American Samoa pop | |
| Spotless Crake | Porzana tabuensis tabuensis | Species of Concern | | |
| Spottail Darter | Etheostoma squamiceps | Not Listed | | |
| Spotted Algae-Eating Goby | Sicydium punctatum | Not Listed | | |
| Spotted Bass | Micropterus punctulatus | Not Listed | | |
| Spotted bat | Euderma maculatum | Species of Concern | Wherever found | |
| Spotted cave beetle | Pseudanophthalmus punctatus | Species of Concern | Wherever found | |
| Spotted darter | Etheostoma maculatum | Resolved Taxon | Wherever found | |
| Spotted Darter | Nothonotus maculatus | Not Listed | | |
| Spotted Leaf-nosed Snake | Phyllorhynchus decurtatus | Not Listed | | |
| Spotted linsang | Prionodon pardicolor | Endangered | Wherever found | 06-14-1976 |
| Spotted madtom | Noturus insignis ssp. | Species of Concern | Wherever found | |
| Spotted pond turtle | Geoclemys hamiltonii | Endangered | Wherever found | 06-14-1976 |
| Spotted rocksnail | Leptoxis picta | Under Review | Wherever found | |
| Spotted Salamander | Ambystoma maculatum | Status Undefined | Wherever found | |
| Spotted Seal | Phoca largha | Threatened | Southern DPS - See 50 CFR 223.102 | 04-13-2011 |
| Spotted Seatrout | Cynoscion nebulosus | Not Listed | | |
| Spotted skunk | Spilogale putorius | Status Undefined | Wherever found | |
| Spotted Sucker | Minytrema melanops | Not Listed | | |
| Spotted Sunfish | Lepomis punctatus | Not Listed | | |
| Spotted Towhee | Pipilo maculatus | Species of Concern | Wherever found | |
| Spotted Towhee | Pipilo maculatus clementae | Species of Concern | Wherever found | |
| Spotted turtle | Clemmys guttata | Under Review | Wherever found | |
| Spotted Warner Valley Dunes june beetle | Polyphylla avittata | Species of Concern | Wherever found | |
| Spp. (ca 12) carelia | Carelia spp. (ca 12) | Species of Concern | Wherever found | |
| Sprague's pipit | Anthus spragueii | Resolved Taxon | Wherever found | |
| Spreading avens | Geum radiatum | Endangered | Wherever found | 04-05-1990 |
| Spreading navarretia | Navarretia fossalis | Threatened | Wherever found | 10-13-1998 |
| Spreading wild-buckwheat | Eriogonum lonchophyllum | Resolved Taxon | Wherever found | |
| Spring amphipod | Stygobromus fontinalis | Resolved Taxon | Wherever found | |
| Spring Cave amphipod | Stygobromus spinatus | Species of Concern | Wherever found | |
| Spring Cavefish | Forbesichthys agassizii | Not Listed | | |
| Spring Creek bladderpod | Lesquerella perforata | Endangered | Wherever found | 12-23-1996 |
| Spring Creek pyrg | Pyrgulopsis sp. | Species of Concern | Spring Creek | |
| Spring elimia | Elimia pybasi | Species of Concern | Wherever found | |
| Spring-flowering goldenrod | Solidago verna | Species of Concern | Wherever found | |
| Spring-loving centaury | Centaurium namophilum | Threatened | Wherever found | 05-20-1985 |
| Spring Mountain comma skipper | Hesperia comma ssp. | Species of Concern | Wherever found | |
| Spring Mountain milk-vetch | Astragalus remotus | Species of Concern | Wherever found | |
| Spring Mountains acastus checkerspot butterfly | Chlosyne acastus robusta | Resolved Taxon | Wherever found | |
| Spring Mountains blue | Plejebus shasta charlestonensis | Species of Concern | Wherever found | |
| Spring Mountains comma skipper butterfly | hesperia comma ssp. mojavensis | Species of Concern | Wherever found | |
| Spring Mountains dark blue butterfly | Euphilotes ancilla cryptica | Resolved Taxon | Wherever found | |
| Spring Mountains dark blue butterfly | Euphilotes ancilla purpura | Resolved Taxon | Wherever found | |
| Spring Mountains icarioides blue | Plejebus icarioides ssp. | Species of Concern | Spring Mts | |
| Spring Mountains icarioides blue butterfly | Plebejus icarioides austinorum | Resolved Taxon | Wherever found | |
| Spring Mountains pyrg | Pyrgulopsis deaconi | Resolved Taxon | Wherever found | |
| Spring Peeper | Pseudacris crucifer | Not Listed | | |
| Spring pygmy sunfish | Elassoma alabamae | Threatened | Wherever found | 12-02-2013 |
| Spring River crayfish | Faxonius roberti | Resolved Taxon | | |
| Spring Salamander | Gyrinophilus porphyriticus | Not Listed | | |
| Springville clarkia | Clarkia springvillensis | Threatened | Wherever found | 10-14-1998 |
| Spruce Creek snail | Melongena sprucecreekensis | Resolved Taxon | Wherever found | |
| Spruce-fir moss spider | Microhexura montivaga | Endangered | Wherever found | 02-06-1995 |
| Square-stemmed monkey-flower | Mimulus ringens colpophilus | Species of Concern | Wherever found | |
| Squat elimia | Elimia variata | Resolved Taxon | Wherever found | |
| Squaw carpet | Ceanothus prostratus laxus | Resolved Taxon | Wherever found | |
| Squirrel Chimney Cave shrimp | Palaemonetes cummingi | Threatened | Wherever found | 06-21-1990 |
| Sri Lankan Ornamental Tarantula | Poecilotheria fasciata | Endangered | Wherever found | 08-30-2018 |
| stage station milkvetch | Astragalus vehiculus | Not Listed | | |
| Staghorn coral | Acropora cervicornis | Threatened | Wherever found | 06-08-2006 |
| Stairstep two-bristle rock-daisy | Perityle bisetosa scalaris | Species of Concern | Wherever found | |
| Stalked moonwort | Botrychium pedunculosum | Species of Concern | Wherever found | |
| Stalk-leaved monkey-flower | Mimulus patulus | Species of Concern | Wherever found | |
| Standley whitlow-grass | Draba standleyi | Species of Concern | Wherever found | |
| St. Andrew beach mouse | Peromyscus polionotus peninsularis | Endangered | Wherever found | 12-18-1998 |
| Stanley whitlow-grass | Draba trichocarpa | Species of Concern | Wherever found | |
| Stannard's agarodes caddisfly | Agarodes stannardi | Species of Concern | Wherever found | |
| Stansbury Island harvest mouse | Reithrodontomys megalotis ravus | Species of Concern | Wherever found | |
| Stansbury Island pocket gopher | Thomomys umbrinus minimus | Species of Concern | Wherever found | |
| Star cactus | Astrophytum asterias | Endangered | Wherever found | 10-18-1993 |
| Star coral | Montastraea franksi | Status Undefined | Wherever found | |
| Star-fruited, small stonecrop | Sedum radiatum depauperatum | Species of Concern | Wherever found | |
| Stargazing darter | Percina uranidea | Species of Concern | Wherever found | |
| Stargazing Minnow | Phenacobius uranops | Not Listed | | |
| Stark's false water penny | Alabameubria starki | Species of Concern | Wherever found | |
| Star-nosed mole | Condylura cristata parva | Resolved Taxon | Wherever found | |
| Starry Flounder | Platichthys stellatus | Not Listed | | |
| St. Croix ground lizard | Ameiva polops | Endangered | Wherever found | 07-05-1977 |
| St. Croix racer | Alsophis sancticrucis | Resolved Taxon | Wherever found | |
| St. Croix snaketail | Ophiogomphus sp. | Species of Concern | Wherever found | |
| Steamboat buckwheat | Eriogonum ovalifolium var. williamsiae | Endangered | Wherever found | 07-08-1986 |
| Stebbins lewisia | Lewisia stebbinsii | Species of Concern | Wherever found | |
| Stebbins' lomatium | Lomatium stebbinsii | Species of Concern | Wherever found | |
| Stebbins' madia | Madia stebbinsii | Species of Concern | Wherever found | |
| Stebbins' morning-glory | Calystegia stebbinsii | Endangered | Wherever found | 10-18-1996 |
| Stebbins' phacelia | Phacelia stebbinsii | Species of Concern | Wherever found | |
| Steele's meadowrue | Thalictrum coriaceum | Resolved Taxon | Wherever found | |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Endangered | Southern California DPS - See 50 CFR 224.101 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Experimental Population, Non-Essential | Middle Columbia River DPS - XN - See 50 CFR 223.102 | 01-15-2013 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | California Central Valley DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Central California Coast DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Lower Columbia River DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Middle Columbia River DPS - See 50 CFR 223.102 | 08-02-1999 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Northern California DPS - See 50 CFR 223.102 | 08-07-2000 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Puget Sound DPS - See 50 CFR 223.102 | 05-07-2007 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Snake River Basin DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | South-Central California Coast DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Upper Columbia River DPS - See 50 CFR 223.102 | 06-17-1998 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Threatened | Upper Willamette River DPS - See 50 CFR 223.102 | 08-02-1999 |
| Steelhead (Rainbow Trout) | Oncorhynchus (=Salmo) mykiss | Under Review | Klamath Mountains Province steelhead(Oncorhynchus mykiss).Includes all Naturally spawned populations of Steelhead (and their progeny) in coastal river basins ranging from the Elk River in Curry County, Oregon, to the Klamath River, inclusive, in Del Norte County, California | |
| Steen's mountain paintbrush | Castilleja pilosa steenensis | Species of Concern | Wherever found | |
| Stellate Sturgeon | Acipenser stellatus | Proposed Endangered | Wherever found | |
| Steller sea lion | Eumetopias jubatus | Endangered | Western DPS - See 50 CFR 224.101 | 04-10-1990 |
| Steller sea lion | Eumetopias jubatus | Recovery | Eastern DPS - Entire, except the population segment west of 1440 W. Long | 04-05-1990 |
| Steller's Eider | Polysticta stelleri | Threatened | U.S. Alaska breeding population only | 06-11-1997 |
| Stellmack's cave amphipod | Stygobromus stellmacki | Species of Concern | Wherever found | |
| Stemless beardtongue | Penstemon acaulis | Species of Concern | Wherever found | |
| Stephan's Riffle beetle | Heterelmis stephani | Resolved Taxon | Wherever found | |
| Stephen Island frog | Leiopelma hamiltoni | Endangered | Wherever found | 06-02-1970 |
| Stephens' beardtongue | Penstemon stephensii | Species of Concern | Wherever found | |
| Stephens' California vole | Microtus californicus stephensi | Species of Concern | Wherever found | |
| Stephens' kangaroo rat | Dipodomys stephensi (incl. D. cascus) | Threatened | Wherever found | 09-30-1988 |
| Steptoe Valley crescentspot | Phyciodes cocyta arenacolor | Resolved Taxon | Wherever found | |
| Sterile Basin pyrg | Pyrgulopsis sterilis | Under Review | Wherever found | |
| Sterile milk-vetch | Astragalus sterilis | Resolved Taxon | Wherever found | |
| Sterlings lips | Graphis sterlingiana | Species of Concern | | |
| Stevens' tortricid moth | Decodes stevensi | Species of Concern | Wherever found | |
| St. Francis River Crayfish | Faxonius quadruncus | Threatened | | 05-30-2023 |
| Sthenele wood nymph | Cercyonis sthenele sthenele | Resolved Taxon | Wherever found | |
| Stick-nest rat | Leporillus conditor | Endangered | Wherever found | 06-04-1973 |
| Sticky-leaved liveforever | Dudleya viscida | Resolved Taxon | Wherever found | |
| Sticky phacelia | Phacelia lenta | Species of Concern | Wherever found | |
| Sticky ringstem | anulocaulis leiosolenus | Species of Concern | Wherever found | |
| Stimpson'S Goby, `O`Opu Nopili | Sicyopterus stimpsoni | Not Listed | | |
| Stingingbush | Malpighia infestissima | Species of Concern | Wherever found | |
| Stink bells | Fritillaria agrestis | Resolved Taxon | Wherever found | |
| Stippled Darter | Etheostoma punctulatum | Not Listed | | |
| Stippled studfish | Fundulus bifax | Status Undefined | | |
| Stirrupshell | Quadrula stapes | Extinction | Wherever found | 04-07-1987 |
| St. Johns elephantear | Elliptio monroensis | Status Undefined | Wherever found | |
| St. Lucia Forest thrush | Cichlherminia iherminieri santaeluciae | Endangered | Wherever found | 09-16-2010 |
| St. Lucia house wren | Troglodytes aedon mesoleucus | Endangered | Wherever found | 06-02-1970 |
| St. Lucia parrot | Amazona versicolor | Endangered | Wherever found | 06-02-1970 |
| St. Maarten Pejerry | Melanorhinus boekei | Not Listed | | |
| St. Mathew vole | Microtus abbreviatus | Status Undefined | Wherever found | |
| Stock Island tree snail | Orthalicus reses (not incl. nesodryas) | Threatened | Wherever found | 08-02-1978 |
| Stocky pebblesnail | Somatogyrus crassus | Species of Concern | Wherever found | |
| Stoddard's yellow-throated warbler | Dendroica dominica stoddardi | Species of Concern | Wherever found | |
| Stolon whitlow-grass | Draba sobolifera | Species of Concern | Wherever found | |
| Stonecat | Noturus flavus | Not Listed | | |
| Stone Corral Canyon monardella | Monardella scelerata | Resolved Taxon | Wherever found | |
| Stonecrop Gily flower | Gilia sedifolia | Resolved Taxon | Wherever found | |
| Stone-dwelling cave beetle | Pseudanophthalmus hypolithos | Species of Concern | Wherever found | |
| Stone Mountain fairy shrimp | Branchinella lithaca | Resolved Taxon | Wherever found | |
| Stones River bladderpod | Paysonia stonensis | Resolved Taxon | Wherever found | |
| Straight-horned markhor | Capra falconeri megaceros | Threatened | Wherever found | 10-07-2014 |
| Straight snowfly | Capnia lineata | Resolved Taxon | Wherever found | |
| Straley's cave beetle | Pseudanophthalmus quadratus | Species of Concern | Wherever found | |
| Strange itodacnus click beetle | Itodacnus paradoxus | Species of Concern | Wherever found | |
| Streaked Horned lark | Eremophila alpestris strigata | Threatened | Wherever found | 11-04-2013 |
| Streamside Salamander | Ambystoma barbouri | Under Review | Wherever found | |
| Strecker's Chorus Frog | Pseudacris streckeri | Not Listed | | |
| strecker's pocket gopher | geomys streckeri | Status Undefined | Wherever found | |
| Stresemann's bristlefront | Merulaxis stresemanni | Status Undefined | Wherever found | |
| Striated darter | Etheostoma striatulum | Under Review | Wherever found | |
| Striated Hydrobe | Texapyrgus longleyi | Resolved Taxon | Wherever found | |
| Striate slitshell | Gyrotoma lewisii | Resolved Taxon | Wherever found | |
| Striped Bass | Morone saxatilis | Not Listed | | |
| Striped Bass | Morone saxatilis | Status Undefined | Striped bass hybrid (x Morone americana hybrid) | |
| Striped Bass | Morone saxatilis | Status Undefined | Sunshine bass hybrid (x Morone chrysops) | |
| Striped newt | Notophthalmus perstriatus | Resolved Taxon | Wherever found | |
| Striped rhyncogonus weevil | Rhyncogonus vittatus | Species of Concern | Wherever found | |
| Striped rocksnail | Leptoxis vittata | Resolved Taxon | Wherever found | |
| Striped smoothhound shark | Mustelus fasciatus | Endangered | | |
| Strohbeen's parnassian | Parnassius clodius strohbeeni | Resolved Taxon | Wherever found | |
| Strong bladder-pod | Lesquerella valida | Resolved Taxon | Wherever found | |
| Stronghold Canyon Talussnail | Sonorella dragoonensis | Resolved Taxon | Wherever found | |
| St. Thomas lidpod | Operculina turpethum var. turpethum | Species of Concern | Wherever found | |
| St. Thomas prickly-ash | Zanthoxylum thomasianum | Endangered | Wherever found | 12-20-1985 |
| Stump-tailed macaque | Macaca arctoides | Threatened | Wherever found | 10-19-1976 |
| Sturgeon chub | Macrhybopsis gelida | Resolved Taxon | Wherever found | |
| St Vincent parrot | Amazona guildingii | Endangered | Wherever found | 06-02-1970 |
| Subcarinate mountain snail | Oreohelix specieseleven | Under Review | Wherever found | |
| Sub-globose Snake pyrg | Pyrgulopsis saxatilis | Resolved Taxon | Wherever found | |
| Sub-globose Steptoe Ranch pyrg | Pyrgulopsis orbiculata | Under Review | Wherever found | |
| Subtle cave amphipod | Stygobromus subtilis | Species of Concern | Wherever found | |
| Subtropical blue-black tiger beetle | Cicindela nigrocoerulea subtropica | Species of Concern | Wherever found | |
| Sucarnoochee River crayfish | Orconectes jonesi | Status Undefined | Wherever found | |
| Suckermouth Minnow | Phenacobius mirabilis | Not Listed | | |
| Suckley's cuckoo bumble bee | Bombus suckleyi | Proposed Endangered | | |
| Sugarfoot moth fly | Nemopalpus nearcticus | Species of Concern | Wherever found | |
| Sugarspoon | Epioblasma arcaeformis | Resolved Taxon | Wherever found | |
| Suisun aster | Aster chilensis lentus | Species of Concern | Wherever found | |
| Suisun ornate shrew | Sorex ornatus sinuosus | Species of Concern | Wherever found | |
| Suisun thistle | Cirsium hydrophilum var. hydrophilum | Endangered | Wherever found | 11-20-1997 |
| Suksdorf's desert-parsley | Lomatium suksdorfii | Species of Concern | Wherever found | |
| Sulawesi forest turtle | Leucocephalon yuwonoi | Under Review | | |
| Sulfur-flowered, alpine buckwheat | Eriogonum umbellatum minus | Resolved Taxon | Wherever found | |
| Sulphur Springs buckwheat | Eriogonum argophyllum | Resolved Taxon | Wherever found | |
| Sulphur Springs hydroporus diving beetle | Hydroporus sulphurius | Species of Concern | Wherever found | |
| Sumatran rhinoceros | Dicerorhinus sumatrensis | Endangered | Wherever found | 06-02-1970 |
| Summer Basin tui chub | Gila bicolor ssp. | Species of Concern | Summer Basin | |
| Summer Flounder | Paralichthys dentatus | Not Listed | | |
| Summer-holly | Comarostaphylis diversifolia diversifolia | Species of Concern | Wherever found | |
| Summer tanager | piranga rubra | Species of Concern | Wherever found | |
| Sunda pangolin | Manis javanica | Under Review | Wherever found | |
| Sunfacing coneflower | Rudbeckia heliopsidis | Under Review | Wherever found | |
| Superb grasshopper | Eximacris superbum | Species of Concern | Wherever found | |
| Supine bean | Phaseolus supinus | Species of Concern | Wherever found | |
| Supple daisy | Erigeron supplex | Species of Concern | Wherever found | |
| Surf Scoter | Melanitta perspicillata | Species of Concern | Wherever found | |
| Surf thistle | Cirsium rhothophilum | Resolved Taxon | Wherever found | |
| Surprising Cave beetle | Pseudanophthalmus inexpectatus | Resolved Taxon | Wherever found | |
| Susan's purse-making microcaddisfly | Ochrotrichia susanae | Resolved Taxon | Wherever found | |
| Suwanee cooter | Pseudemys concinna suwaniensis | Resolved Taxon | Wherever found | |
| Suwannee alligator snapping turtle | Macrochelys suwanniensis | Threatened | | 07-29-2024 |
| Suwannee moccasinshell | Medionidus walkeri | Threatened | Wherever found | 11-07-2016 |
| Suwannee Pigtoe | Quincuncina kleiniana | Status Undefined | Wherever found | |
| Swainson's hawk | Buteo swainsoni | Species of Concern | CA, NV, OR, CO, AZ or Wherever found | |
| Swainson's Warbler | Limnothlypis swainsonii | Species of Concern | Wherever found | |
| swale paintbrush | Castilleja ornata | Endangered | | 01-06-2025 |
| Swallow spurge | Chamaesyce golondrina | Species of Concern | Wherever found | |
| Swallowtail butterfly | Battus zetides | Status Undefined | Wherever found | |
| Swallowtail butterfly | Eurytides iphitas | Status Undefined | Wherever found | |
| Swallowtail butterfly | Graphium levassori | Status Undefined | Wherever found | |
| Swallowtail butterfly | Graphium sandawanum | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio benguetanus | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio carolinensis | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio desmondi teita | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio himeros | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio leucotaenia | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio maraho | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio moerneri | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio morondavana | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio neumoegeni | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio osmana | Status Undefined | Wherever found | |
| Swallowtail butterfly | Papilio phorbanta | Status Undefined | Wherever found | |
| Swallowtail butterfly | Parides burchellanus | Status Undefined | Wherever found | |
| Swallowtail butterfly | Parides jophon | Status Undefined | Wherever found | |
| Swallowtail butterfly | Parides schadenberqi | Status Undefined | Wherever found | |
| Swallowtail butterfly | Troides croesus | Status Undefined | Wherever found | |
| Swallowtail butterfly | Troides dohertyi | Status Undefined | Wherever found | |
| Swallow-tailed Kite | Elanoides forficatus | Species of Concern | Wherever found | |
| Swamp Darter | Etheostoma fusiforme | Not Listed | | |
| Swamp deer | Cervus duvauceli | Endangered | Wherever found | 06-02-1970 |
| Swampfish | Chologaster cornuta | Not Listed | | |
| Swamp harebell | Campanula californica | Species of Concern | Wherever found | |
| Swamp justiceweed | Eupatorium paludicola | Status Undefined | | |
| swamp milkweed | Asclepias incarnata | Not Listed | | |
| Swamp pink | Helonias bullata | Threatened | | 10-11-1988 |
| Swamp smartweed | Persicaria hydropiperoides | Resolved Taxon | Wherever found | |
| Swasey Spring pocket gopher | Thomomys umbrinus sevieri | Species of Concern | Wherever found | |
| Swayne's hartebeest | Alcelaphus buselaphus swaynei | Endangered | Wherever found | 07-27-1979 |
| Sweadner's olive hairstreak | Mitoura gryneus sweadneri | Species of Concern | Wherever found | |
| Sweet pinesap | Monotropsis odorata | Species of Concern | Wherever found | |
| Sweet, red-flowered pitcher-plant | Sarracenia rubra rubra | Resolved Taxon | Wherever found | |
| Sweetwater Mountains draba | Draba lemmonii incrassata | Resolved Taxon | Wherever found | |
| Swezey's brown lacewing | Micromus swezeyi | Species of Concern | Wherever found | |
| Swezey's long-horned beetle | Plagithmysus swezeyi | Species of Concern | Wherever found | |
| Swezey's zoroapteran | Zorotypus swezeyi | Species of Concern | Wherever found | |
| Swift fox | Vulpes velox | Resolved Taxon | U.S. pop. | |
| Swinhoe's pheasant | Lophura swinhoii | Endangered | Wherever found | 06-02-1970 |
| Sword townsendia | Townsendia spathulata | Resolved Taxon | Wherever found | |
| Sykora's Hydroptila caddisfly | Hydroptila sykorai | Under Review | Wherever found | |
| Sylvan hygrotus diving beetle | Hygrotus sylvanus | Species of Concern | Wherever found | |
| Syr Darya Sturgeon | Pseudoscaphirhynchus fedtschenkoi | Under Review | Wherever found | |
| Tacoma western pocket gopher | Thomomys mazama tacomensis | Resolved Taxon | Wherever found | |
| Tadpole Madtom | Noturus gyrinus | Not Listed | | |
| Tahiti flycatcher | Pomarea nigra | Endangered | Wherever found | 06-02-1970 |
| Tahiti Petrel | Pseudobulweria rostrata | Species of Concern | Wherever found | |
| Tahoe draba | Draba asterophora asterophora | Resolved Taxon | Wherever found | |
| Tahoe haplopappus | Tonestus eximius | Resolved Taxon | Wherever found | |
| Tahoe Sucker | Catostomus tahoensis | Not Listed | | |
| Tahoe yellow cress | Rorippa subumbellata | Resolved Taxon | Wherever found | |
| Tahquitz ivesia | Ivesia callida | Species of Concern | Wherever found | |
| Tailed frog | Ascaphus truei | Species of Concern | Wherever found | |
| Taillight Shiner | Notropis maculatus | Not Listed | | |
| Taita thrush | Turdus olivaceus helleri | Endangered | Wherever found | 01-12-1995 |
| Taiwanese humpback dolphin | Sousa chinensis taiwanensis | Proposed Endangered | | |
| Takahe | Porphyrio hochstetteri | Candidate | | |
| Takahe | Porphyrio mantelli | Under Review | Wherever found | |
| Tallahassee hedge-nettle | Stachys hyssopifolia lythroides | Species of Concern | Wherever found | |
| Tallapoosa orb | Quadrula asperata ssp. archeri | Under Review | Wherever found | |
| Tallapoosa pebblesnail | Somatogyrus pilsbryanus | Species of Concern | Wherever found | |
| Tallapoosa River crayfish | Cambarus englishi | Species of Concern | Wherever found | |
| Tall bugbane | Cimicifuga elata | Species of Concern | Wherever found | |
| Tall larkspur | Delphinium exaltatum | Species of Concern | Wherever found | |
| Tall paintbrush | Castilleja elongata | Resolved Taxon | Wherever found | |
| Tall pebblesnail | Fluminicola spk | Resolved Taxon | Wherever found | |
| Tall western penstemon | Penstemon hesperius | Under Review | | |
| Talus collomia | Collomia debilis var. larsenii | Resolved Taxon | Wherever found | |
| Talus fritillary | Fritillaria falcata | Species of Concern | Wherever found | |
| Tamalpais jewelflower | Streptanthus batrachopus | Species of Concern | Wherever found | |
| Tamalpais manzanita | Arctostaphylos hookeri montana | Species of Concern | Wherever found | |
| Tamaraw | Bubalus mindorensis | Endangered | Wherever found | 12-02-1970 |
| Tamaulipan Agapema | agapema galbina | Resolved Taxon | Wherever found | |
| Tamaulipan spot-tailed earless lizard | Holbrookia subcaudalis | Under Review | Wherever found | |
| Tamaulipas Shiner | Notropis braytoni | Not Listed | | |
| Tampico pearlymussel | Cyrtonaias tampicoensis tecomatensis | Endangered | Wherever found | 06-14-1976 |
| Tana River mangabey | Cercocebus galeritus galeritus | Endangered | Wherever found | 06-02-1970 |
| Tana River red colobus monkey | Procolobus (=Colobus) rufomitratus (=badius r.) | Endangered | Wherever found | 06-02-1970 |
| Tanner's black camel cricket | Utabaenetes tanneri | Species of Concern | Wherever found | |
| Tan riffleshell | Epioblasma florentina walkeri (=E. walkeri) | Endangered | Wherever found | 09-26-1977 |
| Tantula serican scarab | Serica tantula | Species of Concern | Wherever found | |
| Tapered cave beetle | Pseudanophthalmus fastigatus | Species of Concern | Wherever found | |
| Tapered cavesnail | Fontigens holsingeri | Species of Concern | Wherever found | |
| Tapered pigtoe | Fusconaia burkei | Threatened | Wherever found | 10-10-2012 |
| Tarahumara frog | Rana tarahumarae | Species of Concern | Wherever found | |
| Tarpon | Megalops atlanticus | Not Listed | | |
| Tar River spinymussel | Parvaspina steinstansana | Endangered | Wherever found | 06-27-1985 |
| Tarsalis eopenthes click beetle | Eopenthes tarsalis | Species of Concern | Wherever found | |
| (Tartarocreagris) pseudoscorpion | tartarocreagris | Species of Concern | Wherever found | |
| Tartaruga | Podocnemis expansa | Endangered | Wherever found | 06-02-1970 |
| Tasmanian forester kangaroo | Macropus giganteus tasmaniensis | Endangered | Wherever found | 06-04-1973 |
| Tasmanian tiger | Thylacinus cynocephalus | Endangered | Wherever found | 06-02-1970 |
| Tatum Cave beetle | Pseudanophthalmus parvus | Resolved Taxon | Wherever found | |
| Tawny crescent | Phyciodes batesii | Species of Concern | Wherever found | |
| Taylor's (=whulge) Checkerspot | Euphydryas editha taylori | Endangered | Wherever found | 11-04-2013 |
| Teasing Holospira | Holospira tantalus | Resolved Taxon | Wherever found | |
| Tecate cypress | Cupressus forbesii | Species of Concern | Wherever found | |
| Tecate tarweed | Hemizonia floribunda | Species of Concern | Wherever found | |
| Tecopa bird's beak | Chloropyron tecopense | Under Review | | |
| Tecopa pupfish | Cyprinodon nevadensis calidae | Extinction | Wherever found | 10-13-1970 |
| Tehachapi Mountain silverspot | Speyeria egleis tehachapina | Species of Concern | Wherever found | |
| Tehachapi slender salamander | Batrachoseps stebbinsi | Resolved Taxon | Wherever found | |
| Tehachapi white-eared pocket mouse | Perognathus alticola inexpectatus | Species of Concern | Wherever found | |
| Tehama chaparral | Trilobopsis tehamana | Resolved Taxon | Wherever found | |
| Tehama dwarf-flax | Hesperolinon tehamense | Species of Concern | Wherever found | |
| Tehama pincushionplant | Navarretia heterandra | Species of Concern | Wherever found | |
| Tehipite Valley jewelflower | Streptanthus fenestratus | Resolved Taxon | Wherever found | |
| Telegraphic hedyleptan moth | Hedylepta telegrapha | Resolved Taxon | Wherever found | |
| Telephus spurge | Euphorbia telephioides | Threatened | | 05-08-1992 |
| Telescope hornsnail | Pleurocera walkeri | Species of Concern | Wherever found | |
| Telescope Peak bedstraw | Galium hypotrichium tomentellum | Resolved Taxon | Wherever found | |
| Temblor buckwheat | Eriogonum temblorense | Species of Concern | Wherever found | |
| Temblor legless lizard | Anniella alexanderae | Under Review | | |
| Temnick''s ground Pangolin | Manis temminckii | Endangered | Wherever found | 06-14-1976 |
| Tenino pocket gopher | Thomomys mazama tumuli | Threatened | Wherever found | 05-09-2014 |
| Tennessee bottlebrush crayfish | Barbicambarus simmonsi | Under Review | | |
| Tennessee Cave crayfish | Orconectes incomptus | Status Undefined | Wherever found | |
| Tennessee cave salamander | Gyrinophilus palleucus | Resolved Taxon | Wherever found | |
| Tennessee clubshell | Pleurobema oviforme | Proposed Endangered | Wherever found | |
| Tennessee clubtail | Gomphus sandrius | Under Review | Wherever found | |
| Tennessee forestfly | Amphinemura mockfordi | Under Review | Wherever found | |
| Tennessee heelsplitter | Lasmigona holstonia | Resolved Taxon | Wherever found | |
| Tennessee pebblesnail | Somatogyrus currierianus | Species of Concern | Wherever found | |
| Tennessee pigtoe | Pleuronaia barnesiana | Proposed Endangered | Wherever found | |
| Tennessee pondweed | Potamogeton tennesseensis | Under Review | Wherever found | |
| Tennessee purple coneflower | Echinacea tennesseensis | Recovery | Wherever found | 07-05-1979 |
| Tennessee riffleshell | Epioblasma propinqua | Resolved Taxon | Wherever found | |
| Tennessee yellow-eyed grass | Xyris tennesseensis | Endangered | Wherever found | 07-26-1991 |
| Tepic fameflower | Talinum marginatum | Species of Concern | Wherever found | |
| Terciopelo | Abutilon hulseanum | Resolved Taxon | Wherever found | |
| Terlingua bricklebush | Brickellia brachyphylla terlinguensis | Species of Concern | Wherever found | |
| Terlingua Creek cat's-eye | Cryptantha crassipes | Endangered | Wherever found | 09-30-1991 |
| terrestrial snail | sonorella species | Status Undefined | Wherever found | |
| Tessellated Darter | Etheostoma olmstedi | Not Listed | | |
| Texas amorpha | Amorpha roemeriana | Resolved Taxon | Wherever found | |
| Texas asaphomyian tabanid fly | Asaphomyia texanus | Species of Concern | Wherever found | |
| Texas austrotinodes caddisfly | Austrotinodes sp. | Species of Concern | Wherever found | |
| Texas ayenia | Ayenia limitaris | Endangered | Wherever found | 08-24-1994 |
| Texas blind salamander | Eurycea rathbuni | Endangered | Wherever found | 03-11-1967 |
| Texas Botteri's sparrow | Aimophila botterii texana | Species of Concern | Wherever found | |
| Texas cave shrimp | Palaemonetes antrorum | Species of Concern | Wherever found | |
| Texas diamondback terrapin | Malaclemys terrapin littoralis | Species of Concern | Wherever found | |
| Texas emerald | Somatochlora margarita | Status Undefined | Wherever found | |
| Texas fatmucket | Lampsilis bracteata | Endangered | Wherever found | 07-05-2024 |
| Texas fawnsfoot | Truncilla macrodon | Threatened | Wherever found | 07-05-2024 |
| Texas garter snake | Thamnophis sirtalis annectens | Species of Concern | Wherever found | |
| Texas golden Gladecress | Leavenworthia texana | Endangered | Wherever found | 10-11-2013 |
| Texas greasebush | Glossopetalon texense | Not Listed | | |
| Texas heelsplitter | Potamilus amphichaenus | Proposed Endangered | Wherever found | |
| Texas Henslow's sparrow | Ammodramus henslowii houstonensis | Resolved Taxon | Wherever found | |
| Texas horned lizard | Phrynosoma cornutum | Species of Concern | Wherever found | |
| Texas Hornshell | Popenaias popeii | Endangered | Wherever found | 03-12-2018 |
| Texas kangaroo rat | Dipodomys elator | Proposed Endangered | Wherever found | |
| Texas map turtle | Graptemys versa | Resolved Taxon | Wherever found | |
| Texas margay | Leopardus wiedii cooperi | Resolved Taxon | Wherever found | |
| Texas milkvine | Matelea texensis | Resolved Taxon | Wherever found | |
| Texas minute moss beetle | Limnebius texanus | Species of Concern | Wherever found | |
| Texas olive sparrow | Arremonops rufivirgatus rufivirgatus | Species of Concern | Wherever found | |
| Texas Pigtoe | Fusconaia askewi | Not Listed | | |
| Texas pimpleback | Cyclonaias petrina | Endangered | Wherever found | 07-05-2024 |
| Texas Pipefish | Syngnathus affinis | Resolved Taxon | Wherever found | |
| Texas poppy-mallow | Callirhoe scabriuscula | Endangered | Wherever found | 01-13-1981 |
| Texas prairie dawn-flower | Hymenoxys texana | Endangered | Wherever found | 03-13-1986 |
| Texas salamander | Eurycea neotenes | Under Review | Wherever found | |
| Texas screwstem | Bartonia texana | Under Review | | |
| Texas Shiner | Notropis amabilis | Not Listed | | |
| Texas silverside | Menidia clarkhubbsi | Resolved Taxon | Wherever found | |
| Texas Silverside | Menidia clarkhubbsi | Not Listed | | |
| Texas snowbells | Styrax platanifolius ssp. texanus | Endangered | Wherever found | 10-12-1984 |
| Texas Spring Amphipod | Hyalella muerta | Not Listed | | |
| Texas stonecrop | Lenophyllum texanum | Resolved Taxon | Wherever found | |
| Texas sunnybell | Schoenolirion wrightii | Resolved Taxon | Wherever found | |
| Texas trailing phlox | Phlox nivalis ssp. texensis | Endangered | Wherever found | 09-30-1991 |
| Texas trillium | Trillium pusillum texanum | Under Review | | |
| Texas Troglobitic Water Slater | Lirceolus smithii | Resolved Taxon | Wherever found | |
| Texas trumpets | Acleisanthes crassifolia | Species of Concern | Wherever found | |
| Texas wild-rice | Zizania texana | Endangered | Wherever found | 05-27-1978 |
| Texas windmill grass | Chloris texensis | Species of Concern | Wherever found | |
| Texas wolfberry | Lycium texanum | Species of Concern | Wherever found | |
| Tex-Mex Gambusia | Gambusia speciosa | Not Listed | | |
| Thailand giant catfish | Pangasianodon gigas | Endangered | Wherever found | 06-02-1970 |
| Tharp''s bluestar | Amsonia tharpii | Under Review | Wherever found | |
| The Cedars globe-lily | Calochortus raichei | Species of Concern | Wherever found | |
| The Geysers panic grass | Dichanthelium acuminatum acuminatum | Species of Concern | Wherever found | |
| The Lassics sandwort | Minuartia decumbens | Species of Concern | Wherever found | |
| The Needles buckwheat | Eriogonum breedlovei shevockii | Resolved Taxon | Wherever found | |
| Thermophilic ostracod | Potamocypris hunteri | Resolved Taxon | Wherever found | |
| Thick-billed Longspur | Rhynchophanes mccownii | Species of Concern | | |
| Thick-billed Murre | Uria lomvia | Species of Concern | | |
| Thick-billed parrot | Rhynchopsitta pachyrhyncha | Endangered | Wherever found | 06-02-1970 |
| thick-leaf bladderpod | Physaria pachyphylla | Under Review | | |
| Thickleaf Pepperwort | Lepidium integrifolium | Resolved Taxon | Wherever found | |
| Thick-leaved water-willow | Justicia crassifolia | Species of Concern | Wherever found | |
| Thick-lipped pebblesnail | Somatogyrus crassilabris | Species of Concern | Wherever found | |
| Thickshell pondsnail | Stagnicola utahensis | Resolved Taxon | Wherever found | |
| Thicktail chub | Gila crassicauda | Resolved Taxon | Wherever found | |
| Thieret's skullcap | Scutellaria thieretii | Species of Concern | Wherever found | |
| thin-leaved peavine | Lathyrus holochlorus | Not Listed | | |
| Thin-neck cave beetle | Pseudanophthalmus parvicollis | Species of Concern | Wherever found | |
| Thin-spined porcupine | Chaetomys subspinosus | Endangered | Wherever found | 06-02-1970 |
| Thin-wall quillwort | Isoetes microvela | Under Review | Wherever found | |
| Thistle | Cirsium brevifolium | Resolved Taxon | Wherever found | |
| Thistle, Douglas' milk-vetch | Astragalus kentrophyta douglasii | Resolved Taxon | Wherever found | |
| Thomas' cave beetle | Pseudanophthalmus thomasi | Not Listed | Wherever found | |
| Thompkins' sedge | Carex tompkinsii | Resolved Taxon | Wherever found | |
| Thompson, Atwood's wild-buckwheat | Eriogonum thompsonae atwoodii | Species of Concern | Wherever found | |
| Thompson's clover | Trifolium thompsonii | Species of Concern | Wherever found | |
| Thompson's dalea | Psorothamnus thompsoniae var. thompsoniae | Resolved Taxon | Wherever found | |
| Thompson, white-flow wild-buckwheat | Eriogonum thompsonae albiflorum | Resolved Taxon | Wherever found | |
| Thompson wild-buckwheat | Eriogonum thompsonae thompsonae | Resolved Taxon | Wherever found | |
| Thorne's beaked-rush | Rhynchospora thornei | Status Undefined | | |
| Thorne's buckwheat | Eriogonum ericifolium thornei | Species of Concern | Wherever found | |
| Thorne's hairstreak | Mitoura thornei | Resolved Taxon | Wherever found | |
| Thorne's royal larkspur | Delphinium variegatum thornei | Resolved Taxon | Wherever found | |
| Thousand Palms desertsnail | Eremarionta millepalmarum | Species of Concern | Wherever found | |
| Threadfin Shad | Dorosoma petenense | Not Listed | | |
| Thread-leaved bladder-pod | Lesquerella angustifolia | Resolved Taxon | Wherever found | |
| Thread-leaved brodiaea | Brodiaea filifolia | Threatened | Wherever found | 10-13-1998 |
| Thread-leaved penstemon | Penstemon filiformis | Species of Concern | Wherever found | |
| Threecorner milkvetch | Astragalus geyeri triquetrus | Under Review | Wherever found | |
| Three Forks Springsnail | Pyrgulopsis trivialis | Endangered | Wherever found | 05-17-2012 |
| Threehorn Wartyback | Obliquaria reflexa | Not Listed | | |
| Three-keeled Asian turtle | Melanochelys tricarinata | Endangered | Wherever found | 06-14-1976 |
| Three Peaks jewelflower | Streptanthus morrisonii elatus | Species of Concern | Wherever found | |
| Threeridge Mussel | Amblema plicata | Not Listed | | |
| Threespine Stickleback | Gasterosteus aculeatus | Not Listed | | |
| Three-toed Amphiuma | Amphiuma tridactylum | Not Listed | | |
| Three-toed Box Turtle | Terrapene triunguis | Not Listed | | |
| Three-toed woodpecker | picoides tridactylus | Species of Concern | Wherever found | |
| Three-tongued spurge | Chamaesyce chaetocalyx triligulata | Species of Concern | Wherever found | |
| Three-tooth long-horned caddisfly | Triaenodes tridontus | Under Review | Wherever found | |
| Thurber's pilostyles | Pilostyles thurberi | Resolved Taxon | Wherever found | |
| Thurber's reedgrass | Calamagrostis crassiglumis | Species of Concern | Wherever found | |
| Thyolo alethe | Alethe choloensis | Endangered | Wherever found | 01-12-1995 |
| Tibetan antelope | Panthalops hodgsonii | Endangered | Wherever found | 03-29-2006 |
| Tibial scarab | Anomala tibialis | Species of Concern | Wherever found | |
| Tiburon buckwheat | Eriogonum caninum | Resolved Taxon | Wherever found | |
| Tiburon jewelflower | Streptanthus niger | Endangered | Wherever found | 02-03-1995 |
| Tiburon mariposa lily | Calochortus tiburonensis | Threatened | Wherever found | 02-03-1995 |
| Tiburon micro-blind harvestman | Microcina tiburona | Species of Concern | Wherever found | |
| Tiburon paintbrush | Castilleja affinis ssp. neglecta | Endangered | Wherever found | 02-03-1995 |
| Tiburon tarweed | Hemizonia multicaulis vernalis | Species of Concern | Wherever found | |
| Tidestrom beardtongue | Penstemon tidestromii | Species of Concern | Wherever found | |
| Tidewater amphipod | Stygobromus indentatus | Resolved Taxon | Wherever found | |
| Tidewater goby | Eucyclogobius newberryi | Endangered | Wherever found | 02-04-1994 |
| Tidewater interstitial amphipod | Stygobromus araeus | Species of Concern | Wherever found | |
| Tidewater Mucket | Leptodea ochracea | Not Listed | | |
| Tiehm's buckwheat | Eriogonum tiehmii | Endangered | | 01-17-2023 |
| Tiehm's milk-vetch | Astragalus tiehmii | Species of Concern | Wherever found | |
| Tiehm's rock-cress | Arabis tiehmii | Species of Concern | Wherever found | |
| Tiehm's stroganowia | Stroganowia tiehmii | Species of Concern | Wherever found | |
| Tiger | Panthera tigris | Endangered | Wherever found | 06-02-1970 |
| Tiger beardtongue | Penstemon mensarum | Species of Concern | Wherever found | |
| Tiger cat | Leopardus (=Felis) tigrinus | Endangered | Wherever found | 03-28-1972 |
| Tigna Potato | Solanum leptosepalum | Resolved Taxon | Wherever found | |
| Timber bluegrass | Poa rhizomata | Resolved Taxon | Wherever found | |
| Timber rattlesnake | Crotalus horridus | Resolved Taxon | Wherever found | |
| Tinged eopenthes click beetle | Eopenthes tinctus | Species of Concern | Wherever found | |
| Tinian Monarch (old world flycatcher) | Monarcha takatsukasae | Recovery | Wherever found | 06-02-1970 |
| Tiny bog buttons | Lachnocaulon digynum | Species of Concern | Wherever found | |
| tiny mousetail | Myosurus minimus | Species of Concern | Wherever found | |
| Tiny orchid | Lepanthopsis melanantha | Species of Concern | Wherever found | |
| Tiny polygala | Polygala smallii | Endangered | | 07-18-1985 |
| Tippecanoe darter | Nothonotus tippecanoe | Resolved Taxon | Wherever found | |
| Tipton kangaroo rat | Dipodomys nitratoides nitratoides | Endangered | Wherever found | 07-08-1988 |
| Tissue sedge | Carex hyalina | Species of Concern | Wherever found | |
| Tobusch fishhook cactus | Sclerocactus brevihamatus ssp. tobuschii | Threatened | Wherever found | 12-08-1979 |
| Todsen's pennyroyal | Hedeoma todsenii | Endangered | Wherever found | 01-19-1981 |
| Tollhouse Canyon talussnail | Sonorella delicata | Resolved Taxon | Wherever found | |
| Tomah mayfly | Siphlonisca aerodromia | Species of Concern | Wherever found | |
| Tomales clarkia | Clarkia concinna raichei | Species of Concern | Wherever found | |
| Tombigbee Darter | Etheostoma lachneri | Not Listed | | |
| Tombigbee Riverlet crayfish | Hobbseus petilus | Under Review | Wherever found | |
| Tombstone Prairie farulan caddisfly | Farula reapiri | Species of Concern | Wherever found | |
| Tombstone Prairie oligophlebodes caddisfly | Oligophlebodes mostbento | Species of Concern | Wherever found | |
| Tomistoma | Tomistoma schlegelii | Endangered | Wherever found | 06-14-1976 |
| Tonguetied Minnow | Exoglossum laurae | Not Listed | | |
| Tonkin snub-nosed monkey | Rhinopithecus avunculus | Endangered | Wherever found | 10-19-1976 |
| Tonopah milk-vetch | Astragalus iodanthus pseudoiodanthus | Resolved Taxon | Wherever found | |
| Tooth Cave blind rove beetle | Cylindropsis sp. | Resolved Taxon | Wherever found | |
| Tooth Cave ground beetle | Rhadine persephone | Endangered | Wherever found | 09-16-1988 |
| Tooth Cave pseudoscorpion | Tartarocreagris texana | Endangered | Wherever found | 09-16-1988 |
| Tooth Cave spider | Tayshaneta myopica | Endangered | Wherever found | 09-16-1988 |
| Toothless blindcat | Trogloglanis pattersoni | Proposed Endangered | Wherever found | |
| Toothy coil | Helicodiscus hexodon | Species of Concern | Wherever found | |
| Topeka shiner | Notropis topeka (=tristis) | Endangered | Wherever found, except where listed as an experimental population | 12-15-1998 |
| Topeka shiner | Notropis topeka (=tristis) | Experimental Population, Non-Essential | U.S.A. (MO-specified portions of Little Creek, Big Muddy Creek, and Spring Creek watersheds in Adair, Gentry, Harrison, Putnam, Sullivan, and Worth Counties; see 17.84(d)(1)(i)) | 07-17-2013 |
| Toque macaque | Macaca sinica | Threatened | Wherever found | 10-19-1976 |
| Tora hartebeest | Alcelaphus buselaphus tora | Endangered | Wherever found | 07-27-1979 |
| Torrent Sculpin | Cottus rhotheus | Not Listed | | |
| Torreya pygmy grasshopper | Tettigidea empedonepia | Species of Concern | Wherever found | |
| Torreya trap-door spider | Cyclocosmia torreya | Species of Concern | Wherever found | |
| Torrey, Del Mar pine | Pinus torreyana torreyana | Species of Concern | Wherever found | |
| Torrey Island pine | Pinus torreyana insularis | Species of Concern | Wherever found | |
| Torrey's mountainmint | Pycnanthemum torrei | Species of Concern | Wherever found | |
| Torrey's muhly | Muhlenbergia torreyana | Resolved Taxon | Wherever found | |
| Torrey's pea | Lathyrus torreyi | Species of Concern | Wherever found | |
| Tortoise commensal noctuid moth | Idia gopheri | Species of Concern | Wherever found | |
| Total Wreck Talussnail | Sonorella imperatrix | Resolved Taxon | Wherever found | |
| Totoaba (seatrout or weakfish) | Cynoscion macdonaldi | Endangered | Wherever found | 05-21-1979 |
| Townsend's western big-eared bat | plecotus townsendii ssp. pallescens | Species of Concern | Wherever found | |
| Townsend's western big-eared bat | plecotus townsendii ssp. townsendii | Species of Concern | Wherever found | |
| Tracaja | Podocnemis unifilis | Endangered | Wherever found | 06-02-1970 |
| Tracy beardtongue | Penstemon tracyi | Resolved Taxon | Wherever found | |
| Tracy's lupine | Lupinus tracyi | Resolved Taxon | Wherever found | |
| Tracy's sanicle | Sanicula tracyi | Species of Concern | Wherever found | |
| Transient atelothrus ground beetle | Atelothrus transiens | Species of Concern | Wherever found | |
| Trans-Pecos maidenbush | Phyllanthopsis arida | Species of Concern | Wherever found | |
| Trask's cryptantha | Cryptantha traskiae | Resolved Taxon | Wherever found | |
| Trask's milk-vetch | Astragalus traskiae | Species of Concern | Wherever found | |
| Travertine band-thigh diving beetle | Hygrotus fontinalis | Species of Concern | Wherever found | |
| Tree-fern (Tsatsa) | Cyathea lunulata | Status Undefined | Wherever found | |
| Tree pangolin | Manis tricuspis | Under Review | Wherever found | |
| Tree swallow | tachycineta bicolor | Species of Concern | Wherever found | |
| Triangle Floater | Alasmidonta undulata | Not Listed | Wherever Found | |
| Trianglelobe moonwort | Botrychium ascendens | Species of Concern | Wherever found | 09-26-1994 |
| Triangle Pigtoe | Fusconaia lananensis | Resolved Taxon | Wherever found | |
| Triangular Kidneyshell | Ptychobranchus greenii | Endangered | Wherever found | 03-17-1993 |
| Trichoniscidae isopod | trichoniscoides | Species of Concern | Wherever found | |
| Tricolia Mussel | Tricolia pullus | Not Listed | | |
| Tricolored bat | Perimyotis subflavus | Proposed Endangered | Wherever found | |
| Tricolored Blackbird | Agelaius tricolor | Resolved Taxon | Wherever found | |
| Trinidad white-headed curassow | Pipile pipile pipile | Endangered | Wherever found | 06-02-1970 |
| Trinity Alps daisy | Erigeron flexuosus | Resolved Taxon | Wherever found | |
| Trinity Alps ground beetle | Nebria sahlbergii triad | Species of Concern | Wherever found | |
| Trinity bristlesnail | Monadenia setosa | Resolved Taxon | Wherever found | |
| Trinity buckwheat | Eriogonum alpinum | Species of Concern | Wherever found | |
| Trinity phacelia | Phacelia dalesiana | Species of Concern | Wherever found | |
| Triple-ribbed milk-vetch | Astragalus tricarinatus | Endangered | Wherever found | 10-06-1998 |
| Trispot darter | Etheostoma trisella | Threatened | Wherever found | 01-28-2019 |
| Tristam's woodpecker | Dryocopus javensis richardsi | Endangered | Wherever found | 06-02-1970 |
| Tristram's Storm Petrel | Hydrobates tristrami | Species of Concern | Wherever found | |
| Troglobitic groundwater shrimp | Typhlatya monae | Resolved Taxon | Wherever found | |
| Tropical parula | Parula pitiayumi nigrilora | Species of Concern | Wherever found | |
| Tropical Parula | Parula pitiayumi | Species of Concern | Wherever found | |
| Trout-Perch | Percopsis omiscomaycus | Not Listed | | |
| Truckee Barberry | Berberis (=Mahonia) sonnei | Original Data in Error - Taxonomic Revision | | 12-06-1979 |
| Truckee waterweed | Elodea brandegeae | Resolved Taxon | Wherever found | |
| True pigtoe | Pleurobema verum | Species of Concern | Wherever found | |
| Truk greater white-eye | Rukia ruki | Pre-Act Delisted Taxon | Wherever found | |
| Truk Micronesian pigeon | Ducula oceanica teraoki | Status Undefined | Wherever found | |
| Truk monarch | Metabolus rugensis | Resolved Taxon | Wherever found | |
| Trumpeter swan | Cygnus buccinator | Resolved Taxon | Greater Yellowstone (Tri-state) breeding pop (DPS) | |
| Trumpeter swan | Cygnus buccinator | Resolved Taxon | Rocky Mountain Population | |
| Trumpeter swan | Cygnus buccinator | Species of Concern | Wherever found | |
| Tuatara | Sphenodon punctatus | Endangered | Wherever found | 06-02-1970 |
| Tubercled blossom (pearlymussel) | Epioblasma torulosa torulosa | Extinction | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Tubercled blossom (pearlymussel) | Epioblasma torulosa torulosa | Resolved Taxon | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Tubercled rhyncogonus weevil | Rhyncogonus tuberculatus | Species of Concern | Wherever found | |
| Tuckahoe masked shrew | Sorex cinereus nigriculus | Species of Concern | Wherever found | |
| Tuckaseegee darter | Etheostoma blenniodes guttseli | Status Undefined | Wherever found | |
| Tucson shovel-nosed Snake | Chionactis occipitalis klauberi | Resolved Taxon | Wherever found | |
| Tufted Puffin | Fratercula cirrhata | Resolved Taxon | Wherever found | |
| Tui Chub | Siphateles bicolor | Not Listed | | |
| Tulare grasshopper mouse | Onychomys torridus tularensis | Species of Concern | Wherever found | |
| Tulare horkelia | Horkelia tularensis | Species of Concern | Wherever found | |
| tularosa juturnia | juturnia tularosae | Resolved Taxon | Wherever found | |
| Tule white-fronted goose | Anser albifrons elgasi | Resolved Taxon | Wherever found | 03-11-1967 |
| Tulotoma snail | Tulotoma magnifica | Threatened | Wherever found | 01-09-1991 |
| Tulsa Whitelip | Neohelix lioderma | Resolved Taxon | Wherever found | |
| Tumaco seedeater | Sporophila insulata | Status Undefined | Wherever found | |
| Tumamoc globeberry | Tumamoca macdougalii | Original Data in Error - New Information Discovered | Wherever found | 04-29-1986 |
| Tumbling Creek cavesnail | Antrobia culveri | Endangered | Wherever found | 08-14-2002 |
| Tuna Cave roach | Aspiduchus cavernicola | Species of Concern | Wherever found | |
| Tunbridge fern | Hymenophyllum tunbrigense | Species of Concern | Wherever found | |
| Tundra shootingstar | Dodecatheon austrofrigidum | Species of Concern | Wherever found | |
| Tunnel Springs beardtongue | Penstemon concinnus | Species of Concern | Wherever found | |
| Tuolumne coyote-thistle | Eryngium pinnatisectum | Species of Concern | Wherever found | |
| Tuolumne fawn-lily | Erythronium tuolumnense | Species of Concern | Wherever found | |
| Turgid blossom (pearlymussel) | Epioblasma turgidula | Extinction | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Turgid blossom (pearlymussel) | Epioblasma turgidula | Resolved Taxon | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Turkey vulture | cathartes aura | Species of Concern | Wherever found | |
| Turkish rugging | Chorizanthe staticoides chrysacantha | Resolved Taxon | Wherever found | |
| Turks and Caicos iguana | Cyclura carinata carinata | Threatened | Wherever found | 06-22-1983 |
| Turquoise parakeet | Neophema pulchella | Recovery | Wherever found | 06-02-1970 |
| Turtle Mound firefly | Photuris sp. | Species of Concern | Wherever found | |
| Tusayan fameflower | Talinum validulum | Species of Concern | Wherever found | |
| Tuscumbia darter | Etheostoma tuscumbia | Under Review | Wherever found | |
| Tushar indian paintbrush | Castilleja parvula | Species of Concern | Wherever found | |
| Tushar Mountain Whitlow grass | Draba ramulosa | Resolved Taxon | Wherever found | |
| Tuskaloosa darter | Etheostoma douglasi | Species of Concern | Wherever found | |
| Tussock panic grass | Dichanthelium cynodon | Resolved Taxon | Wherever found | |
| Tweedy's pussypaws | Cistanthe tweedyi | Resolved Taxon | Wherever found | |
| Twisselmann's buckwheat | Eriogonum twisselmannii | Species of Concern | Wherever found | |
| Twisselmann's nemacladus | Nemacladus twisselmannii | Species of Concern | Wherever found | |
| Two-bristle rock-daisy | Perityle bisetosa bisetosa | Species of Concern | Wherever found | |
| Two carpeled dwarf-flax | Hesperolinon bicarpellatum | Species of Concern | Wherever found | |
| Two-flowered lathyrus | Lathyrus biflorus | Resolved Taxon | Wherever found | |
| Two-flowered stick-pea | Calliandra biflora | Resolved Taxon | Wherever found | |
| Two-striped garter snake | Thamnophis hammondii | Species of Concern | Wherever found | |
| Two-toed Amphiuma | Amphiuma means | Not Listed | | |
| Uakari (all species) | Cacajao spp. | Endangered | Wherever found | 06-02-1970 |
| Ubick''s gnaphosid spider | Talanites ubicki | Resolved Taxon | Wherever found | |
| Ufa-halomtano | Heritiera longipetiolata | Endangered | Wherever found | 11-02-2015 |
| Uhiuhi | Mezoneuron kavaiense | Endangered | Wherever found | 07-08-1986 |
| Uinta Basin hookless cactus | Sclerocactus wetlandicus | Threatened | Wherever found | 09-15-2009 |
| Uintah beardtongue | Penstemon uintahensis | Resolved Taxon | Wherever found | |
| Uinta Mountains draba | Draba inexpectata | Resolved Taxon | Wherever found | |
| Uinta mountainsnail | Oreohelix eurekensis uinta | Resolved Taxon | Wherever found | |
| Ulugura bush-shrike | Malaconotus alius | Threatened | Wherever found | 01-12-1995 |
| Ulunahele | Cyrtandra kauaiensis | Resolved Taxon | Wherever found | |
| Umbilicate river snail | Leptoxis subglubosa umbilicata | Resolved Taxon | Wherever found | |
| Umbrella sedge | Cyperus grayoides | Species of Concern | Wherever found | |
| Umpqua green-gentian | Frasera fastigiata | Species of Concern | Wherever found | |
| Umpqua mariposa Lily | Calochortus umpquaensis | Resolved Taxon | Wherever found | |
| Umpqua Oregon Chub | Oregonichthys kalawatseti | Species of Concern | Wherever found | |
| Umtanum desert buckwheat | Eriogonum codium | Threatened | Wherever found | 05-23-2013 |
| Unarmored threespine stickleback | Gasterosteus aculeatus williamsoni | Endangered | Wherever found | 10-13-1970 |
| Uncompahgre fritillary butterfly | Boloria acrocnema | Endangered | Wherever found | 06-24-1991 |
| Underwood's mastiff-bat | Eumops underwoodi | Species of Concern | Wherever found | |
| Undescribed amphipod | Crangonyx sp | Status Undefined | Wherever found | |
| Undescribed pine | Pinus | Status Undefined | Wherever found | |
| Unexpected larkspur | Delphinium inopinum | Resolved Taxon | Wherever found | |
| Unicolored eopenthes click beetle | Eopenthes unicolor | Species of Concern | Wherever found | |
| Union County cave beetle | Pseudanophthalmus unionis | Species of Concern | Wherever found | |
| Unique yellow-faced bee | Hylaeus unica | Species of Concern | Wherever found | |
| [Unnamed] adder's-tongue | Ophioglossum concinnum | Resolved Taxon | Wherever found | |
| [Unnamed] adobe-lily | Fritillaria pluriflora | Species of Concern | Wherever found | |
| [Unnamed] alkali grass | Puccinellia nutkaensis | Resolved Taxon | Wherever found | |
| [Unnamed] alumroot | Heuchera americana hispida | Resolved Taxon | Wherever found | |
| [Unnamed] ambrosia | Ambrosia linearis | Species of Concern | Wherever found | |
| [Unnamed] amphipod | Stygobromus hoffmani | Species of Concern | Wherever found | |
| [Unnamed] anemone | Anemone edwardsiana edwardsiana | Resolved Taxon | Wherever found | |
| [Unnamed] anemone | Anemone minima | Resolved Taxon | Wherever found | |
| [Unnamed] anemone | Anemone oregana felix | Resolved Taxon | Wherever found | |
| [Unnamed] anglepod | Matelea alabamensis | Species of Concern | Wherever found | |
| [Unnamed] anglepod | Matelea baldwyniana | Species of Concern | Wherever found | |
| [Unnamed] arrowwood | Viburnum bracteatum | Species of Concern | Wherever found | |
| [Unnamed] ash | Fraxinus anomala lowellii | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Aster greatai | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Aster kingii kingii | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Eucephalus glaucescens | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Eurybia furcata | Species of Concern | Wherever found | |
| [Unnamed] aster | Eurybia hemispherica | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Eurybia schreberi | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Eurybia spinulosa | Species of Concern | Wherever found | |
| [Unnamed] aster | Symphyotrichum dumosum | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Symphyotrichum hallii | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Symphyotrichum kralii | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Symphyotrichum molle | Species of Concern | Wherever found | |
| [Unnamed] aster | Symphyotrichum plumosum | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Symphyotrichum potosinum | Resolved Taxon | Wherever found | |
| [Unnamed] aster | Symphyotrichum X schistosum | Species of Concern | Wherever found | |
| [Unnamed] barberry | Berberis swaseyi | Resolved Taxon | Wherever found | |
| [Unnamed] beaked-rush | Rhynchospora culixa | Species of Concern | Wherever found | |
| [Unnamed] beaked-rush | Rhynchospora decurrens | Species of Concern | Wherever found | |
| [Unnamed] beaked-rush | Rhynchospora globularis saxicola | Resolved Taxon | Wherever found | |
| [Unnamed] beaked-rush | Rhynchospora punctata | Species of Concern | Wherever found | |
| [Unnamed] beard grass | Andropogon arctatus | Resolved Taxon | Wherever found | |
| [Unnamed] beardtongue | Penstemon abietinus | Resolved Taxon | Wherever found | |
| [Unnamed] beardtongue | Penstemon angustifolius dulcis | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon caespitosus suffruticosus | Resolved Taxon | Wherever found | |
| [Unnamed] beardtongue | Penstemon clutei | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon deamii | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon glaucinus | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon leiophyllus | Resolved Taxon | Wherever found | |
| [Unnamed] beardtongue | Penstemon pahutensis | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon pinorum | Resolved Taxon | Wherever found | |
| [Unnamed] beardtongue | Penstemon retrorsus | Species of Concern | Wherever found | |
| [Unnamed] beardtongue | Penstemon rubicundus | Resolved Taxon | Wherever found | |
| [Unnamed] beargrass | Nolina atopocarpa | Species of Concern | Wherever found | |
| [Unnamed] bedstraw | Galium andrewsii gatense | Resolved Taxon | Wherever found | |
| [Unnamed] bedstraw | Galium collomae | Resolved Taxon | Wherever found | |
| [Unnamed] birch | Betula murrayana | Species of Concern | Wherever found | |
| [Unnamed] bittercress | Cardamine rupicola | Resolved Taxon | Wherever found | |
| [Unnamed] bladderpod | Lesquerella humilis | Species of Concern | Wherever found | |
| [Unnamed] bladderpod | Lesquerella paysonii | Species of Concern | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella hitchcockii | Resolved Taxon | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella kingii diversifolia | Resolved Taxon | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella lescurii | Resolved Taxon | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella mcvaughiana | Resolved Taxon | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella parviflora | Resolved Taxon | Wherever found | |
| [Unnamed] bladder-pod | Lesquerella pruinosa | Species of Concern | Wherever found | |
| [Unnamed] blazingstar | Liatris borealis | Species of Concern | Wherever found | |
| [Unnamed] bluebells | Mertensia toyabensis | Resolved Taxon | Wherever found | |
| [Unnamed] blue-star | Amsonia grandiflora | Species of Concern | Wherever found | |
| [Unnamed] blue-star | Amsonia palmeri | Resolved Taxon | Wherever found | |
| [Unnamed] blue-star | Amsonia peeblesii | Resolved Taxon | Wherever found | |
| [Unnamed] blue-star | Amsonia repens | Resolved Taxon | Wherever found | |
| [unnamed] brush-pea | Genistidium dumosum | Under Review | Wherever found | |
| [Unnamed] buckwheat | Eriogonum anemophilum | Species of Concern | Wherever found | |
| [Unnamed] buckwheat | Eriogonum lemmonii | Resolved Taxon | Wherever found | |
| [Unnamed] buckwheat | Eriogonum meledonum | Species of Concern | Wherever found | |
| [Unnamed] buckwheat | Eriogonum viscidulum | Species of Concern | Wherever found | |
| [Unnamed] bur-marigold | Bidens bidentoides bidentoides | Species of Concern | Wherever found | |
| [Unnamed] buttercup | Ranunculus inamoenus subaffinis | Resolved Taxon | Wherever found | |
| [Unnamed] butterfly-pea | Centrosema arenicola | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Agapetus jocassee | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Agarodes alabamensis | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Ceraclea enodis | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Chimarra holzenthali | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Diplectrona rossi | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Helicopsyche paralimnella | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Hydroptila chelops | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Hydroptila englishi | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Hydroptila lagoi | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Hydroptila ouachita | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Lepidostoma etnieri | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Ochotrichia elongiralla | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Polycentropus harrisi | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Psilotreta frontalis | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Setodes epicampes | Resolved Taxon | Wherever found | |
| [Unnamed] caddisfly | Stactiobiella cahaba | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Theliopsyche tallapoosa | Species of Concern | Wherever found | |
| [Unnamed] caddisfly | Wormaldia oconee | Species of Concern | Wherever found | |
| [Unnamed] carpenteria | Carpenteria californica | Resolved Taxon | Wherever found | |
| [Unnamed] catchfly | Silene virginica robusta | Species of Concern | Wherever found | |
| [Unnamed] catseye | Cryptantha breviflora | Resolved Taxon | Wherever found | |
| [Unnamed] catseye | Cryptantha insolita | Species of Concern | Wherever found | |
| [Unnamed] catseye | Cryptantha shackletteana | Species of Concern | Wherever found | |
| [Unnamed] catseye | Cryptantha sobolifera | Resolved Taxon | Wherever found | |
| [Unnamed] catseye | Cryptantha stricta | Resolved Taxon | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus audax | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus conditus | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus exoticus | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus globiceps | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus horni | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus puteanus | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus simulans | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanophthalmus tenebrosus | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanopthalmus gracilis | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanopthalmus sylvaticus | Species of Concern | Wherever found | |
| [Unnamed] cave beetle | Pseudanopthalmus vicarius | Species of Concern | Wherever found | |
| [Unnamed] ceanothus | Ceanothus arboreus | Resolved Taxon | Wherever found | |
| [Unnamed] checkermallow | Sidalcea malvaeflora patula | Species of Concern | Wherever found | |
| [Unnamed] clarkia | Clarkia amoena pacifica | Resolved Taxon | Wherever found | |
| [Unnamed] clarkia | Clarkia amoena whitneyi | Resolved Taxon | Wherever found | |
| [Unnamed] clover | Trifolium barnebyi | Resolved Taxon | Wherever found | |
| [Unnamed] clover | Trifolium calcaricum | Species of Concern | Wherever found | |
| [Unnamed] clover | Trifolium leibergii | Species of Concern | Wherever found | |
| [Unnamed] clover | Trifolium macilentum rollinsii | Species of Concern | Wherever found | |
| [Unnamed] clover | Trifolium neurophyllum | Species of Concern | Wherever found | |
| [Unnamed] clover | Trifolium plumosum amplifolium | Resolved Taxon | Wherever found | |
| [Unnamed] clover | Trifolium plumosum plumosum | Resolved Taxon | Wherever found | |
| [Unnamed] clubmoss | Huperzia acerosa | Resolved Taxon | Wherever found | |
| [Unnamed] columbine | Aquilegia chrysantha chaplinei | Resolved Taxon | Wherever found | |
| [Unnamed] columbine | Aquilegia chrysantha rydbergii | Resolved Taxon | Wherever found | |
| [Unnamed] cory cactus | Coryphantha scheeri uncinata | Resolved Taxon | Wherever found | |
| [Unnamed] cory cactus | Escobaria missouriensis var. marstonii | Resolved Taxon | Wherever found | |
| [Unnamed] cory cactus | Escobaria vivipara var. buoflama | Resolved Taxon | Wherever found | |
| [Unnamed] coyote-thistle | Eryngium petiolatum | Resolved Taxon | Wherever found | |
| [Unnamed] crayfish | Cambarus batchi | Resolved Taxon | Wherever found | |
| [Unnamed] crayfish | Cambarus miltus | Species of Concern | Wherever found | |
| [Unnamed] crayfish | Fallicambarus jeanae | Species of Concern | Wherever found | |
| [Unnamed] crayfish | Orconectes williamsi | Species of Concern | Wherever found | |
| [Unnamed] crayfish | Procambarus ferrugineus | Species of Concern | Wherever found | |
| [Unnamed] crayfish | Procambarus liberorum | Resolved Taxon | Wherever found | |
| [Unnamed] croomia | Croomia pauciflora | Resolved Taxon | Wherever found | |
| [Unnamed] desert-parsley | Lomatium graveolens clarkii | Species of Concern | Wherever found | |
| [Unnamed] dewberry | Rubus trivialis | Resolved Taxon | Wherever found | |
| [Unnamed] diamondflowers | Hedyotis nigricans pulvinata | Species of Concern | Wherever found | |
| [Unnamed] dropseed | Sporobolus pyramidatus | Resolved Taxon | Wherever found | |
| [Unnamed] elktoe | Alasmidonta marginata | Species of Concern | Wherever found | |
| [Unnamed] evening-primrose | Camissonia confertiflora | Resolved Taxon | Wherever found | |
| [Unnamed] evening-primrose | Camissonia megalantha | Species of Concern | Wherever found | |
| [Unnamed] evening-primrose | Camissonia nevadensis | Resolved Taxon | Wherever found | |
| [Unnamed] evening-primrose | Camissonia parryi | Resolved Taxon | Wherever found | |
| [Unnamed] evening-primrose | Camissonia specuicola hesperia | Species of Concern | Wherever found | |
| [Unnamed] evening-primrose | Camissonia specuicola specuicola | Resolved Taxon | Wherever found | |
| [Unnamed] evening-primrose | Oenothera pilosella sessilis | Species of Concern | Wherever found | |
| [Unnamed] evening-primrose | Oenothera psammophila | Species of Concern | Wherever found | |
| [Unnamed] false foxglove | Agalinis setacea | Resolved Taxon | Wherever found | |
| [Unnamed] false indigo | Amorpha ouachitensis | Species of Concern | Wherever found | |
| [Unnamed] fameflower | Phemeranthus parviflorus | Resolved Taxon | Wherever found | |
| [Unnamed] fameflower | Phemeranthus sediformis | Resolved Taxon | Wherever found | |
| [Unnamed] fameflower | Talinum mengesii | Resolved Taxon | Wherever found | |
| [Unnamed] fameflower | Talinum thompsonii | Resolved Taxon | Wherever found | |
| [Unnamed] feverfew | Parthenium ligulatum | Resolved Taxon | Wherever found | |
| [Unnamed] figwort | Scrophularia macrantha | Resolved Taxon | Wherever found | |
| [Unnamed] flax | Linum carteri smallii | Species of Concern | Wherever found | |
| [Unnamed] flax | Linum macrocarpum | Species of Concern | Wherever found | |
| [Unnamed] fleabane | Erigeron calvus | Resolved Taxon | Wherever found | |
| [Unnamed] fleabane | Erigeron latus | Species of Concern | Wherever found | |
| [Unnamed] fleabane | Laennecia eriophylla | Resolved Taxon | Wherever found | |
| [Unnamed] four-o'clock | Mirabilis pudica | Resolved Taxon | Wherever found | |
| [Unnamed] gama grass | Tripsacum floridanum | Species of Concern | Wherever found | |
| [Unnamed] gentian | Gentiana villosa | Resolved Taxon | Wherever found | |
| [Unnamed] geranium | Geranium caespitosum | Resolved Taxon | Wherever found | |
| [Unnamed] ghost moth | Hepialus sciophanes | Species of Concern | Wherever found | |
| [Unnamed] glade cress | Leavenworthia alabamica brachystyla | Resolved Taxon | Wherever found | |
| [Unnamed] glade cress | Leavenworthia crassa elongata | Species of Concern | Wherever found | |
| [Unnamed] glade cress | Leavenworthia exigua lutea | Species of Concern | Wherever found | |
| [Unnamed] globe-mallow | Sphaeralcea fendleri albescens | Resolved Taxon | Wherever found | |
| [Unnamed] goldenweed | Haplopappus fremontii monocephalus | Resolved Taxon | Wherever found | |
| [Unnamed] goldenweed | Lorandersonia salicina | Resolved Taxon | Wherever found | |
| [Unnamed] goldenweed | Pyrrocoma radiata | Species of Concern | Wherever found | |
| [Unnamed] goldenweed | Pyrrocoma uniflora var. uniflora | Resolved Taxon | Wherever found | |
| [Unnamed] green-gentian | Frasera gypsicola | Resolved Taxon | Wherever found | |
| [Unnamed] green-gentian | Frasera pahutensis | Species of Concern | Wherever found | |
| [Unnamed] ground beetle | Rhadine ozarkensis | Species of Concern | Wherever found | |
| [Unnamed] ground beetle | Scaphinotus behrensi | Species of Concern | Wherever found | |
| [Unnamed] ground beetle | Scaphinotus inflectus | Species of Concern | Wherever found | |
| [Unnamed] ground beetle | Scaphinotus parisiana | Species of Concern | Wherever found | |
| [Unnamed] groundsel | Senecio hallii discoidea | Resolved Taxon | Wherever found | |
| [Unnamed] halapepe | Pleomele aurea | Resolved Taxon | Wherever found | |
| [Unnamed] haw | Crataegus harbisonii | Species of Concern | Wherever found | |
| [Unnamed] hawkweed | Hieracium robinsonii | Species of Concern | Wherever found | |
| [Unnamed] heartleaf | Hexastylis lewisii | Resolved Taxon | Wherever found | |
| [Unnamed] holly | Ilex amelanchier | Resolved Taxon | Wherever found | |
| [Unnamed] hornsnail | Pleurocera viridulum | Species of Concern | Wherever found | |
| [Unnamed] horse-mint | Monarda fistulosa brevis | Species of Concern | Wherever found | |
| [Unnamed] horse-mint | Monarda stipitatoglandulosa | Resolved Taxon | Wherever found | |
| [Unnamed] horse-nettle | Solanum carolinense hirsutum | Species of Concern | Wherever found | |
| [Unnamed] hydroid | Ostroumovia horii | Species of Concern | Wherever found | |
| [Unnamed] indian paintbrush | Castilleja scabrida | Resolved Taxon | Wherever found | |
| [Unnamed] indian paintbrush | Castilleja wootonii | Species of Concern | Wherever found | |
| [Unnamed] iris | Iris missouriensis | Species of Concern | Wherever found | |
| [Unnamed] iris | Iris tenax gormanii | Resolved Taxon | Wherever found | |
| [Unnamed] islandsnail | Micrarionta rowelli bakerensis | Species of Concern | Wherever found | |
| [Unnamed] isopod | Caecidotea filicispeluncae | Species of Concern | Wherever found | |
| [Unnamed] isopod | Caecidotea simonini | Species of Concern | Wherever found | |
| [Unnamed] isopod | Caecidotea sinuncus | Species of Concern | Wherever found | |
| [Unnamed] isopod | Caecidotea tomalensis | Species of Concern | Wherever found | |
| Unnamed isopod | Caecidotea acuticarpa | Status Undefined | Wherever found | |
| [Unnamed] jack-bean | Canavalia kauaiensis | Resolved Taxon | Wherever found | |
| [Unnamed] jacob's ladder | Polemonium occidentale lacustre | Species of Concern | Wherever found | |
| [Unnamed] jacob's ladder | Polemonium reptans villosum | Resolved Taxon | Wherever found | |
| [Unnamed] jacob's ladder | Polemonium vanbruntiae | Resolved Taxon | Wherever found | |
| [Unnamed] jewelflower | Streptanthus squamiformis | Species of Concern | Wherever found | |
| [Unnamed] kittentails | Synthyris ranunculina | Resolved Taxon | Wherever found | |
| [Unnamed] knotweed | Polygonum striatulum | Resolved Taxon | Wherever found | |
| [Unnamed] lace bug | Acalyptera susanae | Species of Concern | Wherever found | |
| [Unnamed] ladies'-tresses | Mesadenus polyanthus | Species of Concern | Wherever found | |
| [Unnamed] ladies'-tresses | Spiranthes lanceolata paludicola | Species of Concern | Wherever found | |
| [Unnamed] lady's-slipper | Cypripedium kentuckiense | Species of Concern | Wherever found | |
| [Unnamed] larkspur | Delphinium multiplex | Resolved Taxon | Wherever found | |
| [Unnamed] larkspur | Delphinium newtonianum | Resolved Taxon | Wherever found | |
| [Unnamed] larkspur | Delphinium nuttallianum lineapetalum | Resolved Taxon | Wherever found | |
| [Unnamed] larkspur | Delphinium treleasei | Resolved Taxon | Wherever found | |
| [Unnamed] leather flower | Clematis occidentalis dissecta | Resolved Taxon | Wherever found | |
| [Unnamed] lichen | Texosporium sancti-jacobi | Species of Concern | Wherever found | |
| [Unnamed] linanthus | Linanthus concinnus | Species of Concern | Wherever found | |
| [Unnamed] liverwort | Cylindrocolea andersonii | Species of Concern | Wherever found | |
| [Unnamed] liverwort | Plagiochila sullivantii var. spinigera | Species of Concern | Wherever found | |
| [Unnamed] liverwort | Plagiochila sullivantii var. sullivantii | Species of Concern | Wherever found | |
| [Unnamed] liverwort | Plagiochila virginica var. caroliniana | Species of Concern | Wherever found | |
| [Unnamed] liverwort | Sphenolobopsis pearsoni | Species of Concern | Wherever found | |
| [Unnamed] Liverwort | Plagiochila virginica var. virginica | Species of Concern | | |
| [Unnamed] Liverwort | Porella pinnata | Species of Concern | Wherever found | |
| [Unnamed] looper moth | Euchlaena milnei | Species of Concern | Wherever found | |
| [Unnamed] looper moth | Lambdina canitiaria | Species of Concern | Wherever found | |
| [Unnamed] looper moth | Lytrosis permagnaria | Species of Concern | Wherever found | |
| [Unnamed] manzanita | Arctostaphylos hispidula | Resolved Taxon | Wherever found | |
| [Unnamed] manzanita | Arctostaphylos intricata oblongifolia | Resolved Taxon | Wherever found | |
| [Unnamed] maple | Acer grandidentatum sinuosum | Resolved Taxon | Wherever found | |
| [Unnamed] mariposa lily | Calochortus indecorus | Species of Concern | Wherever found | |
| [Unnamed] mayfly | Paraleptophlebia calcarica | Resolved Taxon | Wherever found | |
| [Unnamed] milkpea | Galactia pinetorum | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus accumbens | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus ackermanii | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus aequalis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus altus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus alvordensis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus amnis-amissi | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus atratus inseptus | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus barrii | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus brandegeei | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus calycosus monophyllidius | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus camptopus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus ceramicus apus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus cimae sufflatus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus consobrinus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus convallarius finitimus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus drabelliformis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus ensiformis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus eurylobus | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus gilmanii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus harrisonii | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus henrimontanensis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus hoodianus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus howellii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus knightii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lancearius | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lentiformis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lentiginosus latus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lentiginosus maricopae | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lentiginosus pohlii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lentiginosus scorpionis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus loanus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus lutosus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus minthorniae gracilior | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus molybdenus | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus monumentalis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus neglectus | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus nidularius | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus nyensis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus oniciformis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus oocalycis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus panamintensis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus pardalinus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus pauperculus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus paysonii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus peckii | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus porrectus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus preussii cutleri | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus proimanthus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus proximus | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus pterocarpus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus puniceus gertrudis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus purshii ophiogenes | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus scaphoides | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus serenoi sordescens | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus serpens | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus shultziorum | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus siliceus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus subvestitus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus tegetarioides | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus tennesseensis | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus titanophilus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus toquimanus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus troglodytus | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus tweedyi | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus tyghensis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus uncialis | Species of Concern | Wherever found | |
| [Unnamed] milk-vetch | Astragalus wittmannii | Resolved Taxon | Wherever found | |
| [Unnamed] milk-vetch | Astragalus woodruffii | Resolved Taxon | Wherever found | |
| [Unnamed] milkweed | Asclepias uncialis | Species of Concern | Wherever found | |
| [Unnamed] milkweed | Asclepias viridula | Species of Concern | Wherever found | |
| [Unnamed] millipede | Toltecus chihuanus | Species of Concern | Wherever found | |
| [Unnamed] mint | Dicerandra odoratissima | Resolved Taxon | Wherever found | |
| [Unnamed] mint | Dicerandra radfordiana | Species of Concern | Wherever found | |
| [Unnamed] monkeyflower | Mimulus guttatus arenicola | Resolved Taxon | Wherever found | |
| [Unnamed] morning-glory | Ipomoea plummerae | Resolved Taxon | Wherever found | |
| [Unnamed] mountain-mint | Pycnanthemum monotrichum | Resolved Taxon | Wherever found | |
| [Unnamed] mountainsnail | Oreohelix haydeni corugata | Species of Concern | Wherever found | |
| [Unnamed] mountainsnail | Oreohelix parowanensis | Species of Concern | Wherever found | |
| [Unnamed] muhly | Muhlenbergia curtisetosa | Resolved Taxon | Wherever found | |
| [Unnamed] nehe | Lipochaeta alata alata | Resolved Taxon | Wherever found | |
| [Unnamed] nightshade | Solanum bahamense rugelii | Resolved Taxon | Wherever found | |
| [Unnamed] noctuid moth | Luperina trigona | Species of Concern | Wherever found | |
| [Unnamed] noctuid moth | Papaipema aerata | Species of Concern | Wherever found | |
| [Unnamed] noctuid moth | Papaipema aweme | Species of Concern | Wherever found | |
| [Unnamed] noctuid moth | Schinia indiana | Species of Concern | Wherever found | |
| [Unnamed] nodding-caps | Triphora latifolia | Species of Concern | Wherever found | |
| [Unnamed] nodding-caps | Triphora yucatanensis | Species of Concern | Wherever found | |
| [Unnamed] oak | Quercus arkansana | Resolved Taxon | Wherever found | |
| [Unnamed] oak | Quercus georgiana | Resolved Taxon | Wherever found | |
| [Unnamed] olapa | Cheirodendron trigynum rockii | Resolved Taxon | Wherever found | |
| [Unnamed] olapa | Cheirodendron trigynum subcordatum | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium constrictum | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium madidum | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium oxyphilum | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium perdulce sperryi | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium robinsonii | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium scilloides | Resolved Taxon | Wherever found | |
| [Unnamed] onion | Allium speculae | Species of Concern | Wherever found | |
| [Unnamed] onion | Allium tolmiei persimile | Resolved Taxon | Wherever found | |
| [Unnamed] ostracod | Dactylocythere isabelae | Species of Concern | Wherever found | |
| [Unnamed] ostracod | Waltoncythere acuta | Species of Concern | Wherever found | |
| [Unnamed] phacelia | Phacelia capitata | Resolved Taxon | Wherever found | |
| [Unnamed] phacelia | Phacelia demissa heterotricha | Resolved Taxon | Wherever found | |
| [Unnamed] phacelia | Phacelia filiformis | Resolved Taxon | Wherever found | |
| [Unnamed] phacelia | Phacelia minutissima | Species of Concern | Wherever found | |
| [Unnamed] phacelia | Phacelia rafaelensis | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox caryophylla | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox jonesii | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox missoulensis | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox mollis | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox pulchra | Resolved Taxon | Wherever found | |
| [Unnamed] phlox | Phlox pungens | Species of Concern | Wherever found | |
| [Unnamed] pinkroot | Spigelia loganioides | Species of Concern | Wherever found | |
| [Unnamed] pitcher-plant | Sarracenia leucophylla | Species of Concern | Wherever found | |
| [Unnamed] planarian | Kenkia glandulosa | Species of Concern | Wherever found | |
| [Unnamed] planarian | Kenkia rhynchida | Species of Concern | Wherever found | |
| [Unnamed] planarian | Procotyla typhlops | Species of Concern | Wherever found | |
| [Unnamed] planarian | Sphalloplana virginiana | Species of Concern | Wherever found | |
| [Unnamed] pondweed | Potamogeton confervoides | Species of Concern | Wherever found | |
| [Unnamed] pondweed | Potamogeton ogdenii | Resolved Taxon | Wherever found | |
| [Unnamed] popcornflower | Plagiobothrys lamprocarpus | Resolved Taxon | Wherever found | |
| [Unnamed] poppy-mallow | Callirhoe bushii | Resolved Taxon | Wherever found | |
| [Unnamed] prairie-clover | Dalea scariosa | Resolved Taxon | Wherever found | |
| [Unnamed] primrose | Primula alcalina | Species of Concern | Wherever found | |
| [Unnamed] primrose | Primula capillaris | Species of Concern | Wherever found | |
| [Unnamed] primrose | Primula domensis | Resolved Taxon | Wherever found | |
| [Unnamed] primrose | Primula nevadensis | Species of Concern | Wherever found | |
| [Unnamed] primrose | Primula tschuktschorum | Species of Concern | Wherever found | |
| [Unnamed] primrose | Primula wilcoxiana | Resolved Taxon | Wherever found | |
| [Unnamed] quillwort | Isoetes flaccida | Resolved Taxon | Wherever found | |
| [Unnamed] reedgrass | Calamagrostis nubila | Resolved Taxon | Wherever found | |
| [Unnamed] reedgrass | Calamagrostis tweedyi | Resolved Taxon | Wherever found | |
| [Unnamed] rhododendron | Rhododendron austrinum | Resolved Taxon | Wherever found | |
| [Unnamed] riffle beetle | Microcylleopus fomicoideus | Species of Concern | Wherever found | |
| [Unnamed] riffle beetle | Microcylleopus similis | Species of Concern | Wherever found | |
| [Unnamed] rock-cress | Arabis crandallii | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis dispar | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis falcatoria | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis falcifructa | Species of Concern | Wherever found | |
| [Unnamed] rock-cress | Arabis gracilipes | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis gunnisoniana | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis koehleri stipitata | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis ophira | Species of Concern | Wherever found | |
| [Unnamed] rock-cress | Arabis petiolaris | Resolved Taxon | Wherever found | |
| [Unnamed] rock-cress | Arabis williamsii | Resolved Taxon | Wherever found | |
| [Unnamed] rock-daisy | Perityle gilensis salensis | Resolved Taxon | Wherever found | |
| [Unnamed] rock-daisy | Perityle lindheimeri halimifolia | Resolved Taxon | Wherever found | |
| [Unnamed] rock-daisy | Perityle lindheimeri lindheimeri | Resolved Taxon | Wherever found | |
| [Unnamed] rosemary | Conradina grandiflora | Species of Concern | Wherever found | |
| [Unnamed] rosinweed | Silphium brachiatum | Species of Concern | Wherever found | |
| [Unnamed] rosinweed | Silphium integrifolium gattingeri | Resolved Taxon | Wherever found | |
| [Unnamed] rush | Juncus gymnocarpus | Resolved Taxon | Wherever found | |
| [Unnamed] rush | Juncus oronensis | Resolved Taxon | Wherever found | |
| [Unnamed] sand grass | Calamovilfa brevipilis | Resolved Taxon | Wherever found | |
| [Unnamed] sand grass | Calamovilfa brevipilis calvipes | Resolved Taxon | Wherever found | |
| [Unnamed] sand grass | Calamovilfa curtissii | Species of Concern | Wherever found | |
| [Unnamed] sand-verbena | Abronia ammphila | Species of Concern | Wherever found | |
| [Unnamed] sand-verbena | Abronia bigelovii | Resolved Taxon | Wherever found | |
| [Unnamed] sand-verbena | Abronia turbinata | Resolved Taxon | Wherever found | |
| [Unnamed] saxifrage | Saxifraga careyana | Resolved Taxon | Wherever found | |
| [Unnamed] scurf-pea | Pediomelum castoreum | Species of Concern | Wherever found | |
| [Unnamed] scurf-pea | Pediomelum epipsilum | Species of Concern | Wherever found | |
| [Unnamed] sea-lavender | Limonium carolinianum angustatum | Resolved Taxon | Wherever found | |
| [Unnamed] sebucan | Leptocereus quadricostatus | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex arapahoensis | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex austrocaroliniana | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex baltzellii | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex bicknellii opaca | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex decomposita | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex fissa | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex formosa | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex haysii | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex interrupta | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex lenticularis dolia | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex misera | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex onusta | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex oronensis | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex parryana idahoa | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex purpurifera | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex roanensis | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex schweinitzii | Species of Concern | Wherever found | |
| [Unnamed] sedge | Carex scirpoidea curatorum | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Carex socialis | Resolved Taxon | Wherever found | |
| [Unnamed] sedge | Cyperus louisianensis | Species of Concern | Wherever found | |
| [Unnamed] service-berry | Amelanchier nantucketensis | Species of Concern | Wherever found | |
| [Unnamed] shrimp | Halocaridina palahemo | Species of Concern | Wherever found | |
| [Unnamed] silverbells | Styrax platanifolia stellata | Resolved Taxon | Wherever found | |
| [Unnamed] skullcap | Scutellaria saxatilis | Resolved Taxon | Wherever found | |
| [Unnamed] snail | Diastole schmeltziana | Species of Concern | Wherever found | |
| [Unnamed] snail | Laminella sanguinea | Species of Concern | Wherever found | |
| [Unnamed] snail | Leptachatina lepida | Species of Concern | Wherever found | |
| [Unnamed] snail | Mesodon clausus trossulus | Species of Concern | Wherever found | |
| [Unnamed] snail | Neoplanorbis carinatus | Species of Concern | Wherever found | |
| [Unnamed] snail | Neoplanorbis smithi | Species of Concern | Wherever found | |
| [Unnamed] snail | Neoplanorbis tantillus | Species of Concern | Wherever found | |
| [Unnamed] snail | Neoplanorbis umbilicatus | Species of Concern | Wherever found | |
| [Unnamed] snail | Paravitrea aulacogyra | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella carinella | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella fulgurans | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella helena | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella kuhnsi | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella mauiensis | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella ornata | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella thwingii | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella zebra | Species of Concern | Wherever found | |
| [Unnamed] snail | Perdicella zebrina | Species of Concern | Wherever found | |
| [Unnamed] snail | Succinea guamensis | Species of Concern | Wherever found | |
| [Unnamed] snail | Succinea piratarum | Species of Concern | Wherever found | |
| [Unnamed] snail | Succinea quadrasi | Species of Concern | Wherever found | |
| [Unnamed] snail | Trochomorpha apia | Species of Concern | Wherever found | |
| [Unnamed] snail | Valvata virens | Species of Concern | Wherever found | |
| [Unnamed] sorrel | Rumex krausei | Species of Concern | Wherever found | |
| [Unnamed] spider | Cicurina cueva | Resolved Taxon | Wherever found | |
| [Unnamed] spleenwort | Asplenium adiantum-nigrum | Resolved Taxon | Wherever found | |
| [Unnamed] spleenwort | Asplenium heteroresiliens | Species of Concern | Wherever found | |
| [Unnamed] spleenwort | Asplenium kentuckiense | Resolved Taxon | Wherever found | |
| [Unnamed] spleenwort | Asplenium leucostegioides | Resolved Taxon | Wherever found | |
| [Unnamed] spleenwort | Asplenium plenum | Species of Concern | Wherever found | |
| [Unnamed] spring-beauty | Claytonia virginica hammondiae | Species of Concern | Wherever found | |
| [Unnamed] star-grass | Hypoxis sessilis | Resolved Taxon | Wherever found | |
| [Unnamed] stickleaf | Mentzelia nitens leptocaulis | Resolved Taxon | Wherever found | |
| [Unnamed] stickseed | Hackelia ibapensis | Resolved Taxon | Wherever found | |
| [Unnamed] stickseed | Hackelia ophiobia | Resolved Taxon | Wherever found | |
| [Unnamed] stolon | Draba sphaerocarpa | Resolved Taxon | Wherever found | |
| [Unnamed] stonecrop | Sedum pusillum | Resolved Taxon | Wherever found | |
| [Unnamed] stonecrop | Sedum rosea roanensis | Resolved Taxon | Wherever found | |
| [Unnamed] sullivantia | Sullivantia sullivantii | Resolved Taxon | Wherever found | |
| [Unnamed] sumac | Rhus trilobata arenaria | Species of Concern | Wherever found | |
| [Unnamed] synandra | Synandra hispidula | Resolved Taxon | Wherever found | |
| [Unnamed] tamarindillo | Cassia exunguis | Resolved Taxon | Wherever found | |
| [Unnamed] tansy | Sphaeromeria compacta | Species of Concern | Wherever found | |
| [Unnamed] thelypody | Thelypodium texanum | Resolved Taxon | Wherever found | |
| [Unnamed] thistle | Cirsium davisii | Resolved Taxon | Wherever found | |
| [Unnamed] thistle | Cirsium hallii | Resolved Taxon | Wherever found | |
| [Unnamed] thistle | Cirsium hillii | Species of Concern | Wherever found | |
| [Unnamed] thistle | Cirsium longistylum | Species of Concern | Wherever found | |
| [Unnamed] thistle | Cirsium rydbergii | Resolved Taxon | Wherever found | |
| [Unnamed] thistle | Cirsium turneri | Resolved Taxon | Wherever found | |
| [Unnamed] thoroughwort | Eupatorium resinosum kentuckiense | Resolved Taxon | Wherever found | |
| [Unnamed] three-awned grass | Aristida floridana | Resolved Taxon | Wherever found | |
| [Unnamed] townsendia | Townsendia jonesii lutea | Species of Concern | Wherever found | |
| [Unnamed] townsendia | Townsendia mensana | Resolved Taxon | Wherever found | |
| [Unnamed] townsendia | Townsendia rothrockii | Resolved Taxon | Wherever found | |
| [Unnamed] twinpod | Physaria integrifolia monticola | Species of Concern | Wherever found | |
| [Unnamed] twinpod | Physaria saximontana saximontana | Species of Concern | Wherever found | |
| [Unnamed] vervain | Glandularia tampensis | Species of Concern | Wherever found | |
| [Unnamed] virgin's bower | Clematis viorna | Resolved Taxon | Wherever found | |
| [Unnamed] wallflower | Erysimum asperum angustatum | Resolved Taxon | Wherever found | |
| [Unnamed] water-willow | Justicia americana | Resolved Taxon | Wherever found | |
| [Unnamed] whitlow-grass | Draba subalpina | Resolved Taxon | Wherever found | |
| [Unnamed] whitlow-wort | Draba exunguiculata | Resolved Taxon | Wherever found | |
| [Unnamed] whitlow-wort | Paronychia rugelii interior | Resolved Taxon | Wherever found | |
| [Unnamed] wild-buckwheat | Eriogonum ericifolium ericifolium | Resolved Taxon | Wherever found | |
| [Unnamed] wild-buckwheat | Eriogonum flavum aquilinum | Species of Concern | Wherever found | |
| [Unnamed] willow | Salix fluviatilis | Resolved Taxon | Wherever found | |
| [Unnamed] wormwood | Artemisia globularia lutea | Species of Concern | Wherever found | |
| [Unnamed] wormwood | Artemisia glomerata subglabra | Species of Concern | Wherever found | |
| Unsilvered fritillary | Speyeria adiaste | Resolved Taxon | Wherever found | |
| Upland combshell | Epioblasma metastriata | Extinction | Wherever found | 03-17-1993 |
| Upland hornsnail | Pleurocera showalteri | Species of Concern | Wherever found | |
| Upland Sandpiper | Bartramia longicauda | Species of Concern | Wherever found | |
| Urban's flatsedge | Cyperus urbanii | Species of Concern | Wherever found | |
| Urial | Ovis musimon ophion | Endangered | Wherever found | 06-14-1976 |
| Usinger's brown lacewing | Pseudopsectra usingeri | Species of Concern | Wherever found | |
| Utah Amphipod | Stygobromus utahensis | Resolved Taxon | Wherever found | |
| Utah chaetarthrian water scavenger beetle | Chaetarthria utahensis | Resolved Taxon | Wherever found | |
| Utah Chub | Gila atraria | Not Listed | | |
| Utah hydroporus diving beetle | Hydroporus utahensis | Species of Concern | Wherever found | |
| Utah minute moss beetle | Limnebius utahensis | Species of Concern | Wherever found | |
| Utah phacelia | Phacelia utahensis | Species of Concern | Wherever found | |
| Utah physa | Physella utahensis | Species of Concern | Wherever found | |
| Utah prairie dog | Cynomys parvidens | Threatened | Wherever found | 06-04-1973 |
| Utah Sucker | Catostomus ardens | Not Listed | | |
| Utah valvata snail | Valvata utahensis | Original Data in Error - New Information Discovered | Wherever found | 12-14-1992 |
| Ute ladies'-tresses | Spiranthes diluvialis | Threatened | Wherever found | 01-17-1992 |
| Utila chachalaca | Ortalis vetula | Resolved Taxon | Wherever found | |
| Uvea parakeet | Eunymphicus uveaensis | Resolved Taxon | Wherever found | |
| Uvillo | Eugenia haematocarpa | Endangered | Wherever found | 11-25-1994 |
| Vahl's boxwood | Buxus vahlii | Endangered | Wherever found | 08-13-1985 |
| Vail Lake ceanothus | Ceanothus ophiochilus | Threatened | Wherever found | 10-13-1998 |
| Valdina Farms salamander | Eurycea troglodytes | Resolved Taxon | Wherever found | |
| Valentine's cave spider | Nesticus valentinei | Species of Concern | Wherever found | |
| Valley elderberry longhorn beetle | Desmocerus californicus dimorphus | Threatened | Wherever found | 08-08-1980 |
| Valley Form ground snake | sonora semiannulata | Species of Concern | Wherever found | |
| Valley mydas fly | Drosophila alsophila | Resolved Taxon | Wherever found | |
| Valley mydas fly | Drosophila psilotarsalis | Resolved Taxon | Wherever found | |
| Valley mydas fly | Drosophila toxochaeta | Resolved Taxon | Wherever found | |
| Valley Oak | Quercus lobata | Resolved Taxon | Wherever found | |
| Valley oak ant | Proceratium californicum | Under Review | Wherever found | |
| Valley peperomia | Peperomia remyi | Resolved Taxon | Wherever found | |
| Valley sagittaria | Sagittaria sanfordii | Species of Concern | Wherever found | |
| Valley spearscale | Atriplex joaquiniana | Species of Concern | Wherever found | |
| Vancouver Island marmot | Marmota vancouverensis | Endangered | Wherever found | 01-23-1984 |
| Van Dam's vanga | Xenopirostris damii | Threatened | Wherever found | 01-12-1995 |
| Vandenberg monkeyflower | Diplacus vandenbergensis | Endangered | Wherever found | 09-25-2014 |
| Van Dyke's salamander | plethodon vandykei | Species of Concern | Wherever found | |
| Vannote's net-spinning caddisfly | Cheumatopsyche vannotei | Species of Concern | Wherever found | |
| Van Rossem's gull-billed tern | Sterna nilotica vanrossemi | Resolved Taxon | Wherever found | |
| Variable Cuckoo Bumble Bee | Bombus variabilis | Under Review | | |
| Variable leaf Indian plaintain | Arnoglossum diversifolium | Status Undefined | | |
| Variable sedge | Carex polymorpha | Species of Concern | Wherever found | |
| Variable Spike | Elliptio icterina | Not Listed | | |
| Variable Vertigo | Vertigo gouldi | Not Listed | | |
| Varicose rocksnail | Lithasia verrucosa | Species of Concern | Wherever found | |
| Varied Bunting | Passerina versicolor | Species of Concern | Wherever found | |
| Varied Thrush | Ixoreus naevius | Species of Concern | | |
| Varied Thrush | Ixoreus naevius naevius | Species of Concern | Wherever found | |
| Variegate Darter | Etheostoma variatum | Not Listed | | |
| Variegated clubtail | Progomphus bellei | Species of Concern | Wherever found | |
| Variegated dudleya | Dudleya variegata | Species of Concern | Wherever found | |
| Variegated false water penny | Dicranopselaphus variegatus | Species of Concern | Wherever found | |
| Vaux's swift | Chaetura vauxi | Species of Concern | Wherever found | |
| Vaux's Swift | Chaetura vauxi vauxi | Species of Concern | | |
| Veery | Catharus fuscescens | Species of Concern | Wherever found | |
| Veery | Catharus fuscescens fuscescens | Species of Concern | | |
| Veery | Catharus fuscescens salicicola | Species of Concern | | |
| Veery | Catharus fuscescens subpallidus | Species of Concern | | |
| Vegas Valley leopard frog | Rana fisheri | Resolved Taxon | Wherever found | |
| Veiny monardella | Monardella douglasii venosa | Species of Concern | Wherever found | |
| Velvet ant | Dasymutilla imperialis | Resolved Taxon | Wherever found | |
| Velvet ant | Dasymutilla nocturna | Resolved Taxon | Wherever found | |
| Velvety false-lupine | Thermopsis macrophylla semota | Species of Concern | Wherever found | |
| Venator Canyon, Shelly's ivesia | Ivesia rhypara shellyi | Species of Concern | Wherever found | |
| Ventura Marsh Milk-vetch | Astragalus pycnostachyus var. lanosissimus | Endangered | Wherever found | 05-21-2001 |
| Venus flytrap | Dionaea muscipula | Resolved Taxon | Wherever found | |
| Venus flytrap noctuid | Hemipachnolia subporphyria subporphyria | Species of Concern | Wherever found | |
| Verde four-nerve daisy | Tetraneuris verdiensis | Resolved Taxon | Wherever found | |
| Verde Rim springsnail | Pyrgulopsis glandulosa | Species of Concern | Wherever found | |
| Verde Valley sage | Salvia dorrii mearnsii | Species of Concern | Wherever found | |
| Verdin | Auriparus flaviceps | Species of Concern | Wherever found | |
| Verdin | Auriparus flaviceps acaciarum | Species of Concern | | |
| Verity's dudleya | Dudleya verityi | Threatened | Wherever found | 01-29-1997 |
| Vermilion darter | Etheostoma chermocki | Endangered | Wherever found | 11-28-2001 |
| Vermillion flycatcher | pyrocephalus rubinus | Species of Concern | Wherever found | |
| Vernal barley | hordeum intercedens | Species of Concern | Wherever found | |
| Vernal pool brodiaea | Dichelostemma lacuna-vernalis | Resolved Taxon | Wherever found | |
| Vernal pool fairy shrimp | Branchinecta lynchi | Threatened | Wherever found | 09-19-1994 |
| Vernal pool tadpole shrimp | Lepidurus packardi | Endangered | Wherever found | 09-19-1994 |
| Vertrees's ceraclean caddisfly | Ceraclea vertreesi | Species of Concern | Wherever found | |
| Vertrees's ochrotrichian micro caddisfly | Ochrotrichia vertreesi | Species of Concern | Wherever found | |
| Very yellow-faced bee | Hylaeus flavifrons | Species of Concern | Wherever found | |
| Vespid | Euparagia | Resolved Taxon | Wherever found | |
| Vicinan yellow-faced bee | Hylaeus vicina | Species of Concern | Wherever found | |
| Victorville shoulderband | Helminthoglypta mohaveana | Species of Concern | Wherever found | |
| Vicuna | Vicugna vicugna | Endangered | Ecuador (DPS) | 06-02-1970 |
| Vicuna | Vicugna vicugna | Threatened | Entire, except Ecuador | 07-01-2002 |
| Villard's pincushion cactus | Escobaria villardii | Species of Concern | Wherever found | |
| Villosan flightless seed bug | Nesocryptias villosa | Species of Concern | Wherever found | |
| Villous muhly | Muhlenbergia villiflora var. villosa | Resolved Taxon | Wherever found | |
| Vinaceous-breasted parrot | Amazona vinacea | Endangered | Wherever found | 06-14-1976 |
| Vine Hill ceanothus | Ceanothus foliosus vineatus | Species of Concern | Wherever found | |
| Vine Hill clarkia | Clarkia imbricata | Endangered | Wherever found | 10-22-1997 |
| Vine Hill manzanita | Arctostaphylos densiflora | Species of Concern | Wherever found | |
| Virgate halimolobus | Halimolobos virgata | Resolved Taxon | Wherever found | |
| Virginia big-eared bat | Corynorhinus (=Plecotus) townsendii virginianus | Endangered | Wherever found | 12-31-1979 |
| Virginia fringed mountain snail | Polygyriscus virginianus | Endangered | Wherever found | 08-02-1978 |
| Virginia mallow | Sida hermaphrodita | Resolved Taxon | Wherever found | |
| Virginia northern flying Squirrel | Glaucomys sabrinus fuscus | Recovery | Wherever found | 07-31-1985 |
| Virginia quillwort | Isoetes virginica | Species of Concern | Wherever found | |
| Virginia Rail | Rallus limicola | Status Undefined | Wherever found | |
| Virginia round-leaf birch | Betula uber | Threatened | Wherever found | 05-27-1978 |
| Virginia saltmarsh mallow | Kosteletzkya pentacarpos | Resolved Taxon | Wherever found | |
| Virginia sneezeweed | Helenium virginicum | Threatened | Wherever found | 11-03-1998 |
| Virginia spiraea | Spiraea virginiana | Threatened | Wherever found | 06-15-1990 |
| Virginia stone | Acroneuria kosztarabi | Under Review | Wherever found | |
| Virginia's Warbler | Leiothlypis virginiae | Species of Concern | Wherever found | |
| Virgin Islands Bronze Skink | Spondylurus sloanii | Proposed Endangered | Wherever found | |
| Virgin Islands coqui | Eleutherodactylus schwartzi | Resolved Taxon | Wherever found | |
| Virgin Islands screech owl | Otus nudipes newtoni | Species of Concern | Wherever found | |
| Virgin Islands tree boa | Chilabothrus granti | Endangered | Wherever found | 10-13-1970 |
| Virgin Merriam's kangaroo rat | Dipodomys merriami frenatus | Species of Concern | Wherever found | |
| Virgin phacelia | Phacelia cephalotes | Resolved Taxon | Wherever found | |
| Virgin River Chub | Gila seminuda (=robusta) | Endangered | Wherever found | 08-24-1989 |
| Virgin River montane vole | Microtus montanus rivularis | Species of Concern | Wherever found | |
| Virgin River spinedace | Lepidomeda mollispinis mollispinis | Resolved Taxon | Wherever found | |
| Virgin Spinedace | Lepidomeda mollispinis | Not Listed | | |
| Virgin Spinedace | Lepidomeda mollispinis | Not Listed | | |
| Virgin thistle | Cirsium mohavense | Species of Concern | Wherever found | |
| Virile Amargosa snail | Undescribed sp. | Resolved Taxon | Wherever found | |
| Visayan deer | Cervus alfredi | Endangered | Wherever found | 09-01-1988 |
| Viznaga | Ferocactus acanthodes acanthodes | Resolved Taxon | Wherever found | |
| Volatile yellow-faced bee | Hylaeus volatilis | Species of Concern | Wherever found | |
| Volcanic melicope | Melicope volcanica | Resolved Taxon | Wherever found | |
| Volcanoes cave cricket | Thaumatogryllus cavicola | Species of Concern | Wherever found | |
| Volcano rabbit | Romerolagus diazi | Endangered | Mexico | 06-02-1970 |
| Vollmer's lily | Lilium pardalinum ssp. vollmeri | Resolved Taxon | Wherever found | |
| Volutine stonemyian tabanid fly | Stonemyia volutina | Resolved Taxon | Wherever found | |
| Voodoo Whiff | Citharichthys uhleri | Not Listed | | |
| Wabash belted skimmer | Macromia taeniolata | Species of Concern | Wherever found | |
| Wabash Pigtoe | Fusconaia flava | Not Listed | | |
| Waccamaw darter | Etheostoma perlongum | Resolved Taxon | Wherever found | |
| Waccamaw fatmucket | Lampsilis fullerkati | Status Undefined | Wherever found | |
| Waccamaw killifish | Fundulus waccamensis | Species of Concern | Wherever found | |
| Waccamaw lance | Elliptio sp. | Species of Concern | Wherever found | |
| Waccamaw silverside | Menidia extensa | Threatened | Wherever found | 04-08-1987 |
| Waccamaw spike | Elliptio waccamawensis | Species of Concern | Wherever found | |
| Wahaula heiau | Rauvolfia remotiflora | Resolved Taxon | Wherever found | |
| wahine noho Kula | Isodendrion pyrifolium | Endangered | Wherever found | 03-04-1994 |
| Wahkeena Falls flightless stonefly | Zapada wahkeena | Species of Concern | Wherever found | |
| Waianae megalagrion damselfly | Megalagrion amaurodytum waianaeanum | Species of Concern | Wherever found | |
| Wai`anae tetraplasandra | Tetraplasandra waianensis | Resolved Taxon | Wherever found | |
| Waianae tree snail | Partulina dubia | Species of Concern | Wherever found | |
| Wailupe leafroller | Spheterista reynoldsiana | Species of Concern | Wherever found | |
| Wakulla seaside sparrow | Ammodramus maritimus juncicola | Resolved Taxon | Wherever found | |
| Waldo buckwheat | Eriogonum pendulum | Resolved Taxon | Wherever found | |
| Waldo daisy | Erigeron bloomeri nudatus | Resolved Taxon | Wherever found | |
| Waldo rock-cress | Arabis aculeolata | Resolved Taxon | Wherever found | |
| Walia ibex | Capra walie | Endangered | Wherever found | 06-02-1970 |
| Walker's manioc | Manihot walkerae | Endangered | Wherever found | 10-02-1991 |
| Wallace's cave beetle | Pseudanophthalmus wallacei | Species of Concern | Wherever found | |
| Wallace's deepwater mayfly | Spinadis simplex | Species of Concern | Wherever found | |
| Wall Canyon sucker | Catostomus sp. | Under Review | Wherever found | |
| Walleye | Sander vitreus | Not Listed | | |
| Wallowa beardtongue | Penstemon spatulatus | Resolved Taxon | Wherever found | |
| Wallowa primrose | Primula cusickiana | Resolved Taxon | Wherever found | |
| Walnut Canyon Talussnail | Sonorella coltoniana | Resolved Taxon | Wherever found | |
| Walnut elimia | Elimia bellula | Status Undefined | Wherever found | |
| Walpole poppy | Papaver walpolei | Resolved Taxon | Wherever found | |
| Walrus | Odobenus rosmarus | Not Listed | | |
| Wandering oodemas weevil | Oodemas erro | Species of Concern | Wherever found | |
| Wandering skipper | Panoquina errans | Species of Concern | Wherever found | |
| Wandering Tattler | Tringa incana | Species of Concern | | |
| Ward beardtongue | Penstemon wardii | Species of Concern | Wherever found | |
| Ward's Amphipod | Stygobromus wardi | Resolved Taxon | Wherever found | |
| Warm Springs pupfish | Cyprinodon nevadensis pectoralis | Endangered | Wherever found | 10-13-1970 |
| Warm Springs Zaitzevian riffle beetle | Zaitzevia posthonia | Resolved Taxon | Wherever found | |
| Warner hawthorn | Crataegus warneri | Species of Concern | Wherever found | |
| Warner Mountains bedstraw | Galium serpenticum warnerense | Resolved Taxon | Wherever found | |
| Warner's dodder | Cuscuta warneri | Species of Concern | Wherever found | |
| Warner Springs lessingia | Lessingia glandulifera tomentosa | Species of Concern | Wherever found | |
| Warner sucker | Catostomus warnerensis | Threatened | Wherever found | 09-27-1985 |
| Warner Valley redband trout | Oncorhynchus mykiss ssp. | Species of Concern | Wherever found | |
| Warrior bridled darter | Percina sp. | Species of Concern | Warrior bridled | |
| Warrior darter | Etheostoma bellator | Status Undefined | Wherever found | |
| Warrior pigtoe | Pleurobema rubellum | Status Undefined | Wherever found | |
| Warton cave meshweaver | Cicurina wartoni | Resolved Taxon | Wherever found | |
| Wart-stemmed ceanothus | Ceanothus verrucosus | Species of Concern | Wherever found | |
| Wartyback | Cyclonaias nodulata | Not Listed | | |
| Warty rocksnail | Lithasia lima | Species of Concern | Wherever found | |
| Wasatch Draba | Draba brachystylis | Resolved Taxon | Wherever found | |
| Wasatch pika | Ochotona princeps wasatchensis | Species of Concern | Wherever found | |
| Washboard | Megalonaias nervosa | Not Listed | | |
| Washington duskysnail | Amnicola sp | Resolved Taxon | Wherever found | |
| Washington ground squirrel | Urocitellus washingtoni | Resolved Taxon | Wherever found | |
| Washington monkey-flower | Mimulus washingtonensis washingtonensis | Species of Concern | Wherever found | |
| Watercelery | Vallisneria americana | Not Listed | | |
| Watercress darter | Etheostoma nuchale | Endangered | Wherever found | 10-13-1970 |
| Waterfall's sedge | Carex latebracteata | Species of Concern | Wherever found | |
| Water howellia | Howellia aquatilis | Recovery | | 07-14-1994 |
| Waterhyssop | Bacopa procumbens | Not Listed | | |
| Water-loving checkermallow | Sidalcea oregana hydrophila | Resolved Taxon | Wherever found | |
| Water Stargrass | Heteranthera dubia | Not Listed | | |
| Water stitchwort | Stellaria fontinalis | Not Listed | | |
| Watling Island ground iguana | Cyclura rileyi rileyi | Endangered | Wherever found | 06-22-1983 |
| Watson's Falseclapdaisy | Pseudoclappia watsonii | Not Listed | | |
| Wavyleaf wild-quinine | Parthenium integrifolium | Species of Concern | Wherever found | |
| Wavyrayed Lampmussel | Lampsilis fasciola | Not Listed | | |
| Wawae`iole | Phlegmariurus mannii | Endangered | Wherever found | 05-15-1992 |
| Wawae`iole | Phlegmariurus nutans | Endangered | Wherever found | 03-28-1994 |
| Wawona riffle beetle | Atractelmis wawona | Species of Concern | Wherever found | |
| Wax Coil | Helicodiscus nummus | Resolved Taxon | Wherever found | |
| Wayside aster | Eucephalus vialis | Species of Concern | Wherever found | |
| Weak eopenthes click beetle | Eopenthes debilis | Species of Concern | Wherever found | |
| Weakfish | Cynoscion regalis | Not Listed | | |
| Weak milk-vetch | Astragalus solitarius | Species of Concern | Wherever found | |
| Webber's ivesia | Ivesia webberi | Threatened | Wherever found | 07-03-2014 |
| Webber's milk-vetch | Astragalus webberi | Species of Concern | Wherever found | |
| Weber's catseye | Cryptantha weberi | Resolved Taxon | Wherever found | |
| Weber's Whitlow grass | Draba weberi | Resolved Taxon | Wherever found | |
| Web-footed coqui | Eleutherodactylus karlschmidti | Species of Concern | Wherever found | |
| Webug sucker | Chasmistes fecundus | Resolved Taxon | Wherever found | |
| Wedge-leaved horkelia | Horkelia cuneata sericea | Species of Concern | Wherever found | |
| Wedge spurge | Chamaesyce deltoidea serpyllum | Endangered | | 10-31-2016 |
| Wedge-winged metromenus ground beetle | Metromenus cuneipennis | Species of Concern | Wherever found | |
| Weed Shiner | Notropis texanus | Status Undefined | Wherever found | |
| Weist's sphinx moth | Euproserpinus wiesti | Resolved Taxon | Wherever found | |
| Wekiu bug | Nysius wekiuicola | Resolved Taxon | Wherever found | |
| Wekiwa hydrobe | Aphaostracon monas | Status Undefined | Wherever found | |
| Wekiwa siltsnail | Cincinnatia wekiwae | Status Undefined | Wherever found | |
| Welch's rhyncogonus weevil | Rhyncogonus welchii | Species of Concern | Wherever found | |
| Welder machearanthera | Psilactis heterocarpa | Species of Concern | Wherever found | |
| Weller's salamander | Plethodon welleri | Resolved Taxon | Wherever found | |
| Well's pixie-moss | Pyxidanthera barbulata brevifolia | Species of Concern | Wherever found | |
| Welsh phacelia | Phacelia welshii | Species of Concern | Wherever found | |
| Welsh's cryptantha | Cryptantha welshii | Species of Concern | Wherever found | |
| Welsh's milkweed | Asclepias welshii | Threatened | Wherever found | 10-28-1987 |
| Wenatchee larkspur | Delphinium viridescens | Resolved Taxon | Wherever found | |
| Wenatchee Mountains checkermallow | Sidalcea oregana var. calva | Endangered | Wherever found | 12-22-1999 |
| Wengerors' cave amphipod | Stygobromus wengerorum | Resolved Taxon | Wherever found | |
| West African manatee | Trichechus senegalensis | Threatened | Wherever found | 10-16-1979 |
| West African ostrich | Struthio camelus spatzi | Endangered | Wherever found | 06-02-1970 |
| Western Banded Gecko | Coleonyx variegatus | Not Listed | | |
| Western benitoa | Benitoa occidentalis | Resolved Taxon | Wherever found | |
| Western bluebird | sialia mexicana | Species of Concern | Wherever found | |
| Western bog aster | Aster paludicola | Resolved Taxon | Wherever found | |
| Western bog violet | Viola primulifolia occidentalis | Species of Concern | Wherever found | |
| western (boreal) toad | Anaxyrus boreas | Status Undefined | Wherever found | |
| Western bristlebird | Dasyornis longirostris (=brachypterus I.) | Endangered | Wherever found | 06-02-1970 |
| Western brook lamprey | Lampetra richardsoni | Resolved Taxon | Wherever found | |
| Western Bumble bee | Bombus occidentalis | Under Review | Wherever found | |
| Western Burrowing Owl | Athene cunicularia hypugaea | Species of Concern | Wherever found | |
| Western Chicken turtle | Deirochelys reticularia ssp. miaria | Under Review | Wherever found | |
| Western dichondra | Dichondra occidentalis | Resolved Taxon | Wherever found | |
| Western fanshell | Cyprogenia aberti | Threatened | Wherever found | 07-27-2023 |
| Western Floater | Anodonta kennerlyi | Not Listed | | |
| Western giant eland | Taurotragus derbianus derbianus | Endangered | Wherever found | 07-27-1979 |
| Western glacier stonefly | Zapada glacier | Threatened | Wherever found | 12-23-2019 |
| Western gray kangaroo | Macropus fuliginosus | Recovery | Wherever found | 12-30-1974 |
| Western Grebe | aechmophorus occidentalis | Species of Concern | Wherever found | |
| Western grey squirrel | Sciurus griseus | Resolved Taxon | Wherever found | |
| Western Gull | Larus occidentalis | Species of Concern | | |
| Western hare wallaby | Lagorchestes hirsutus | Endangered | Wherever found | 12-02-1970 |
| Western Joshua Tree | Yucca brevifolia | Not Listed | | |
| Western lily | Lilium occidentale | Endangered | Wherever found | 08-17-1994 |
| Western long-nosed snake | rhinocheilus lecontei ssp. lecontei | Species of Concern | Wherever found | |
| Western Meadowlark | Sturnella neglecta | Species of Concern | Wherever found | |
| Western Mosquitofish | Gambusia affinis | Not Listed | | |
| Western mouse | Pseudomys occidentalis | Endangered | Wherever found | 12-02-1970 |
| Western Pearlshell | Margaritifera falcata | Not Listed | | |
| Western prairie fringed Orchid | Platanthera praeclara | Threatened | Wherever found | 09-28-1989 |
| western red-backed salamander | Plethodon vehiculum | Status Undefined | Wherever found | |
| Western redback salamander | plethodon vehiculum | Species of Concern | Wherever found | |
| Western red-tailed skink | eumeces gilberti ssp. rubricaudatus | Species of Concern | Wherever found | |
| Western red-tailed skink | Plestiodon gilberti rubricaudatus | Not Listed | | |
| Western regal fritillary | Argynnis idalia occidentalis | Proposed Threatened | Wherever found | |
| western ridged mussel | Gonidea angulata | Under Review | | 07-27-2021 |
| Western rufous bristlebird | Dasyornis broadbenti littoralis | Endangered | Wherever found | 06-14-1976 |
| Western Sand Darter | Ammocrypta clara | Not Listed | | |
| Western Screech Owl | Megascops kennicottii | Status Undefined | Wherever found | |
| Western Screech-Owl | Megascops kennicottii cardonensis | Species of Concern | | |
| Western Screech-Owl | Megascops kennicottii kennicottii | Species of Concern | | |
| Western silvery minnow | Hybognathus argyritis | Species of Concern | Wherever found | |
| Western Snowy Plover | Charadrius nivosus nivosus | Threatened | Pacific Coast population DPS-U.S.A. (CA, OR, WA), Mexico (within 50 miles of Pacific coast) | 03-05-1993 |
| Western spadefoot | Spea hammondii | Not Listed | Wherever found | |
| Western spadefoot | Spea hammondii | Proposed Threatened | Northern Distinct Population Segment | |
| Western spadefoot | Spea hammondii | Proposed Threatened | Southern Distinct Population Segment | |
| Western Spotted Skunk | Spilogale gracilis | Not Listed | | |
| Western toad | Bufo boreas | Species of Concern | Wherever found | |
| Western tragopan pheasant | Tragopan melanocephalus | Endangered | Wherever found | 06-02-1970 |
| Western whipbird | Psophodes nigrogularis | Endangered | Wherever found | 06-02-1970 |
| Westfall's clubtail | Gomphus westfalli | Under Review | Wherever found | |
| West Florida cow-lily | Nuphar lutea ssp. ulvacea | Status Undefined | | |
| West Indian Manatee | Trichechus manatus | Threatened | Wherever found | 03-11-1967 |
| West Indian Walnut (=Nogal) | Juglans jamaicensis | Endangered | Wherever found | 01-13-1997 |
| West Indian Whistling-Duck | Dendrocygna arborea | Species of Concern | Puerto Rico | |
| West's flax | Linum westii | Under Review | Wherever found | |
| Westslope cutthroat trout | Oncorhynchus clarkii lewisi | Resolved Taxon | Wherever found | 03-11-1967 |
| West Virginia burrowing mayfly | Ephemera triplex | Species of Concern | Wherever found | |
| West Virginia spring salamander | Gyrinophilus subterraneus | Proposed Endangered | Wherever found | |
| West Wills Valley cave beetle | Pseudanophthalmus assimilis | Species of Concern | Wherever found | |
| Wet Canyon talussnail | Sonorella macrophallus | Status Undefined | Wherever found | |
| Wetherill milk-vetch | Astragalus wetherillii | Resolved Taxon | Wherever found | |
| Wet Mountains yellow-bellied marmot | Marmota flaviventris notioros | Resolved Taxon | Wherever found | |
| Wet-rock physa | Physella zionis | Resolved Taxon | Wherever found | |
| Wharton's dewberry | Rubus whartoniae | Species of Concern | Wherever found | |
| Wheeler's peperomia | Peperomia wheeleri | Endangered | Wherever found | 01-14-1987 |
| Wherry's pitcherplant | Sarracenia alabamensis ssp. wherryi | Under Review | Wherever found | |
| Wherry's Sweet pitcher-plant | Sarracenia rubra ssp. wherryi | Under Review | Wherever found | |
| Whetstone Holospira | Holospira whetstonensis | Resolved Taxon | Wherever found | |
| Whetstone Talussnail | Sonorella insignis | Resolved Taxon | Wherever found | |
| Whimbrel | Numenius phaeopus | Species of Concern | Wherever found | |
| Whimbrel | Numenius phaeopus hudsonicus | Species of Concern | | |
| Whip `ena`ena | Gnaphalium sandwicensium flagellare | Resolved Taxon | Wherever found | |
| Whipple's claopodium moss | claopodium whippleanum | Species of Concern | Wherever found | |
| Whipple's monkey-flower | Mimulus whipplei | Species of Concern | Wherever found | |
| Whiskered Auklet | Aethia pygmaea | Species of Concern | Wherever found | |
| Whiskered Screech-Owl | Megascops trichopsis | Species of Concern | | |
| Whistling Frog | Eleutherodactylus cochranae | Resolved Taxon | Wherever found | |
| White Abalone | Haliotis sorenseni | Endangered | North America (West Coast from Point Conception, CA, U.S.A., to Punta Abreojos, Baja California, Mexico) | 11-16-2005 |
| Whitebark pine | Pinus albicaulis | Threatened | Wherever found | 01-17-2023 |
| White Bass | Morone chrysops | Not Listed | | |
| White bear desert-poppy | Arctomecon merriamii | Species of Concern | Wherever found | |
| White birds-in-a-nest | Macbridea alba | Threatened | | 05-08-1992 |
| White bladderpod | Physaria pallida | Endangered | Wherever found | 03-11-1987 |
| White blanketflower | Gaillardia aestivalis winkleri | Species of Concern | Wherever found | |
| White Bluffs bladderpod | Physaria douglasii ssp. tuplashensis | Threatened | Wherever found | 05-23-2013 |
| White-bracted, New England thoroughwort | Eupatorium leucolepis novae-angliae | Species of Concern | Wherever found | |
| White-breasted guineafowl | Agelastes meleagrides | Threatened | Wherever found | 01-12-1995 |
| White-breasted Nuthatch | Sitta carolinensis aculeata | Species of Concern | Wherever found | |
| White-breasted thrasher | Ramphocinclus brachyurus | Endangered | Wherever found | 06-02-1970 |
| White-browed tit-spinetail | Leptasthenura xenothorax | Endangered | Wherever found | 07-24-2012 |
| White Catfish | Ameiurus catus | Not Listed | | |
| White catspaw (pearlymussel) | Epioblasma perobliqua | Endangered | Wherever found | 06-14-1976 |
| White Cay ground iguana | Cyclura rileyi cristata | Threatened | Wherever found | 06-22-1983 |
| White-cheeked pintail | Anas bahamensis | Status Undefined | Puerto Rico | |
| White cockatoo | Cacatua alba | Threatened | Wherever found | 06-24-2014 |
| White-collared mangabey | Cercocebus torquatus | Endangered | Wherever found | 10-19-1976 |
| White-collared Seedeater | Sporophila torqueola | Species of Concern | Wherever found | |
| White column cory cactus | Escobaria albicolumnaria | Species of Concern | Wherever found | |
| White Crappie | Pomoxis annularis | Not Listed | | |
| White-crowned Pigeon | Patagioenas leucocephala | Species of Concern | Wherever found | |
| White desertsnail | Eremarionta immaculata | Species of Concern | Wherever found | |
| Whited milk-vetch | Astragalus sinuatus | Species of Concern | Wherever found | |
| White-eared (=buffy tufted-ear) marmoset | Callithrix aurita (=jacchus a.) | Endangered | Wherever found | 05-16-1986 |
| White eared pheasant | Crossoptilon crossoptilon | Endangered | Wherever found | 12-02-1970 |
| White-eared pocket mouse | Perognathus alticola alticola | Species of Concern | Wherever found | |
| White-faced ibis | Plegadis chihi | Species of Concern | Wherever found | |
| White fairypoppy | Meconella oregana | Species of Concern | Wherever found | |
| White-felted paintbrush | Castilleja hololeuca | Resolved Taxon | Wherever found | |
| white-flippered penguin | Eudyptula albosignata | Threatened | Wherever found | 09-02-2010 |
| White-flowered Cinquefoil | Potentilla albiflora | Resolved Taxon | Wherever found | |
| Whiteflower tansyaster | Dieteria canescens var. leucanthemifolia | Resolved Taxon | Wherever found | |
| White-footed tamarin | Saguinus leucopus | Threatened | Wherever found | 10-19-1976 |
| White-footed vole | Arborimus albipes | Species of Concern | Wherever found | |
| White fringeless orchid | Platanthera integrilabia | Threatened | | 10-13-2016 |
| White-haired goldenrod | Solidago albopilosa | Recovery | Wherever found | 04-07-1988 |
| White-haired leatherflower | Clematis albicoma | Resolved Taxon | Wherever found | |
| White-headed Woodpecker | Dryobates albolarvatus | Species of Concern | Wherever found | |
| White-headed Woodpecker | Dryobates albolarvatus gravirostris | Species of Concern | | |
| White Heelsplitter | Lasmigona complanata | Not Listed | | |
| White irisette | Sisyrinchium dichotomum | Endangered | Wherever found | 09-26-1991 |
| Whiteline topminnow | Fundulus albolineatus | Resolved Taxon | Wherever found | |
| White liptooth | Polygyra peregrina | Species of Concern | Wherever found | |
| White-margined penstemon | Penstemon albomarginatus | Under Review | | |
| White meadowbeauty | Rhexia parviflora | Under Review | Wherever found | |
| White Mountains copper | Lycaena rubicus ssp. | Species of Concern | Wherever found | |
| White Mountains ground squirrel | Spermophilus tridecemlineatus monticola | Resolved Taxon | Wherever found | |
| White Mountains icarioides blue | Plejebus icarioides ssp. | Species of Concern | White Mts | |
| White Mountains paintbrush | Castilleja sulphurea | Species of Concern | Wherever found | |
| White Mountains saepiolus blue | Plejebus saepiolus ssp. | Species of Concern | White Mts | |
| White Mountains sandhill skipper | Polites sabuleti albomontana | Species of Concern | Wherever found | |
| White Mountains skipper | Hesperia mirimae ssp. | Species of Concern | Wherever found | |
| White Mountains water penny | Psephenus montanus | Species of Concern | Wherever found | |
| White-naped Crane | Grus vipio | Endangered | Wherever found | 06-14-1976 |
| White-necked crow | Corvus leucognaphalus | Endangered | Wherever found | 04-03-1991 |
| White-necked rockfowl | Picathartes gymnocephalus | Endangered | Wherever found | 06-02-1970 |
| White-nosed saki | Chiropotes albinasus | Endangered | Wherever found | 06-02-1970 |
| White Perch | Morone americana | Not Listed | | |
| White-rayed pentachaeta | Pentachaeta bellidiflora | Endangered | Wherever found | 02-03-1995 |
| Whiterim scurf-pea | Pediomelum subacaule | Resolved Taxon | Wherever found | |
| White River beardtongue | Penstemon scariosus albifluvis | Resolved Taxon | Wherever found | |
| White River desert sucker | Catostomus clarki intermedius | Resolved Taxon | Wherever found | |
| White River speckled dace | Rhinichthys osculus ssp. | Resolved Taxon | White River | |
| White River spinedace | Lepidomeda albivallis | Endangered | Wherever found | 09-12-1985 |
| White River springfish | Crenichthys baileyi baileyi | Endangered | Wherever found | 09-27-1985 |
| White River Valley pyrg | Pyrgulopsis sathos | Resolved Taxon | Wherever found | |
| White River Valley skipper | Hesperia uncas grandiosa | Resolved Taxon | Wherever found | |
| White River wood nymph | Cercyonis pegala ssp. | Species of Concern | White River | |
| White sand bear scarab | Lichnanthe albopilosa | Species of Concern | Wherever found | |
| White Sands pocket gopher | Geomys arenarius brevirostris | Resolved Taxon | Wherever found | |
| White Sands pupfish | Cyprinodon tularosa | Under Review | Wherever found | |
| White Sands woodrat | Neotoma micropus leucophaea | Species of Concern | Wherever found | |
| White sedge | Carex albida | Endangered | Wherever found | 10-22-1997 |
| White Shiner | Luxilus albeolus | Not Listed | | |
| White-sided jackrabbit | Lepus callotis | Resolved Taxon | Wherever found | |
| White-stemmed evening-star | Mentzelia albicaulis | Status Undefined | Wherever found | |
| White sturgeon | Acipenser transmontanus | Endangered | U.S.A. (ID, MT), Canada (B.C.), (Kootenai R. system) | 09-06-1994 |
| White sturgeon | Acipenser transmontanus | Not Listed | Wherever Found | |
| White Sucker | Catostomus commersonii | Not Listed | | |
| White-Tailed Deer | Odocoileus virginianus | Not Listed | | |
| White-tailed Hawk | Buteo albicaudatus | Species of Concern | Wherever found | |
| White-tailed Kite | Elanus leucurus | Species of Concern | Wherever found | |
| White-tailed laurel Pigeon | Columba junoniae | Threatened | Wherever found | 01-12-1995 |
| White-tailed prairie dog | Cynomys leucurus | Resolved Taxon | Wherever found | |
| White-tailed ptarmigan | Lagopus leucura | Status Undefined | Mt. Rainier white-tailed ptarmigan | |
| White-tailed ptarmigan | Lagopus leucura | Status Undefined | Rocky Mountains population | |
| White-tailed ptarmigan | Lagopus leucura | Status Undefined | U.S. Population | |
| White-tailed Tropicbird | Phaethon lepturus catesbyi | Species of Concern | | |
| Whitetail Woodlandsnail | Ashmunella lepiderma | Resolved Taxon | Wherever found | |
| White-throated Ground Dove | Alopecoenas xanthonurus | Species of Concern | | |
| White wartyback (pearlymussel) | Plethobasus cicatricosus | Endangered | Wherever found | 06-14-1976 |
| White wartyback (pearlymussel) | Plethobasus cicatricosus | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1)) | 10-15-2007 |
| Whitewater crayfish ostracod | Dactylocythere prinsi | Species of Concern | Wherever found | |
| Whitewater Creek woodlandsnail | Ashmunella danielsi | Resolved Taxon | Wherever found | |
| White-wicky | Kalmia cuneata | Species of Concern | Wherever found | |
| White-winged cotinga | Xipholena atropurpurea | Endangered | Wherever found | 06-14-1976 |
| White-winged guan | Penelope albipennis | Endangered | Wherever found | 09-28-1990 |
| White-winged Scoter | Melanitta fusca | Species of Concern | Wherever found | |
| White-winged wood duck | Cairina scutulata | Endangered | Wherever found | 06-02-1970 |
| Whiting's dalea | Psorothamnus thompsoniae var. whitingii | Species of Concern | Wherever found | |
| Whitney sedge | Carex whitneyi | Resolved Taxon | Wherever found | |
| Whooping crane | Grus americana | Endangered | Wherever found, except where listed as an experimental population | 03-11-1967 |
| Whooping crane | Grus americana | Experimental Population, Non-Essential | U.S.A. (AL, AR, CO, FL, GA, ID, IL, IN, IA, KY, LA, MI, MN, MS, MO, NC, NM, OH, SC, TN, UT, VA, WI, WV, western half of WY) | 06-26-2001 |
| Whooping crane | Grus americana | Experimental Population, Non-Essential | U.S.A. (CO, ID, FL, NM, UT, and the western half of Wyoming) | 01-22-1993 |
| Whooping crane | Grus americana | Experimental Population, Non-Essential | U.S.A (Southwestern Louisiana) | 02-03-2011 |
| Whorled mountainsnail | Oreohelix vortex | Species of Concern | Wherever found | |
| Whorled Sunflower | Helianthus verticillatus | Endangered | | 08-01-2014 |
| Wicker ancylid | Rhodacme filosa | Species of Concern | Wherever found | |
| Wide-leaf warea | Warea amplexifolia | Endangered | | 04-29-1987 |
| Widemouth blindcat | Satan eurystomus | Proposed Endangered | Wherever found | |
| Widemouth Holospira | Holospira mesolia | Resolved Taxon | Wherever found | |
| Widstoe wild-buckwheat | Eriogonum aretioides | Species of Concern | Wherever found | |
| Wiggins' cholla | Opuntia wigginsii | Resolved Taxon | Wherever found | |
| Wiggin's croton | Croton wigginsii | Resolved Taxon | Wherever found | |
| Wiggins' lily | Lilium pardalinum ssp. wigginsii | Resolved Taxon | Wherever found | |
| Wilbur Springs minute moss beetle | Ochthebius reticulus | Species of Concern | Wherever found | |
| Wilbur Springs shore bug | Saldula usingeri | Resolved Taxon | Wherever found | |
| Wilbur Springs shore fly | Paracoenia calida | Species of Concern | Wherever found | |
| Wild, Hill Country mercury | Argythamnia aphoroides | Species of Concern | Wherever found | |
| Wild Rose Canyon buckwheat | Eriogonum eremicola | Species of Concern | Wherever found | |
| Wild, silvery mercury | Argythamnia argyraea | Resolved Taxon | Wherever found | |
| Wild spiderflower | Tarenaya spinosa | Resolved Taxon | Wherever found | |
| Wild yak | Bos mutus (=grunniens m.) | Endangered | Wherever found | 06-02-1970 |
| Wilkin's harebell | Campanula wilkinsiana | Species of Concern | Wherever found | |
| Wilkinson's whitlow-wort | Paronychia wilkinsonii | Species of Concern | Wherever found | |
| Willamette daisy | Erigeron decumbens | Endangered | Wherever found | 01-25-2000 |
| Willamette silverspot | Speyeria callippe extincta | Resolved Taxon | Wherever found | |
| Willamette Valley larkspur | Delphinium nuttallii ssp. nuttallii | Species of Concern | Wherever found | |
| Willet | Tringa semipalmata | Species of Concern | | |
| Williams' bronze shoulderband | Helminthoglypta arrosa williamsi | Species of Concern | Wherever found | |
| Williamson's Sapsucker | Sphyrapicus thyroideus | Species of Concern | Wherever found | |
| Williamson's Sapsucker | Sphyrapicus thyroideus nataliae | Species of Concern | | |
| Willow Flycatcher | Empidonax traillii | Species of Concern | Wherever found | |
| Willow-leaved bidens | Bidens salicoides | Resolved Taxon | Wherever found | |
| Willowy monardella | Monardella viminea | Endangered | Wherever found | 10-13-1998 |
| Wilson's phalarope | Phalaropus tricolor | Status Undefined | | |
| Wilson's Plover | Charadrius wilsonia | Species of Concern | Wherever found | |
| Wilson's Storm-Petrel | Oceanites oceanicus | Species of Concern | Wherever found | |
| Wilson's warbler | wilsonia pusilla | Species of Concern | Wherever found | |
| Wind's elfin butterfly | Incisalia mossi doudoroffi | Resolved Taxon | Wherever found | |
| Winged Floater | Anodonta nuttalliana | Not Listed | | |
| Winged Mapleleaf | Quadrula fragosa | Endangered | Wherever found, except where listed as an experimental population | 06-20-1991 |
| Winged Mapleleaf | Quadrula fragosa | Experimental Population, Non-Essential | U.S.A. (AL-specified portions of the Tennessee River; see 17.85(a)(1)) | 06-14-2001 |
| Winged spike | Elliptio nigella | Species of Concern | Wherever found | |
| winged water-starwort | Callitriche marginata | Species of Concern | Wherever found | |
| Wing-shoulder minute moss beetle | Ochthebius crassalus | Species of Concern | Wherever found | |
| Wing Snaggletooth | Gastrocopta procera | Not Listed | | |
| Wingtail crayfish | Procambarus latipleurum | Resolved Taxon | Wherever found | |
| Winkler cactus | Pediocactus winkleri | Threatened | Wherever found | 08-20-1998 |
| Winter Flounder | Pseudopleuronectes americanus | Not Listed | | |
| Winter quillwort | Isoetes hyemalis | Status Undefined | | |
| Wintu sideband | Monadenia troglodytes ssp. wintu | Under Review | Wherever found | |
| Wiregrass gentian | Gentiana pennelliana | Species of Concern | Wherever found | |
| Wireleaf dropseed | Sporobolus teretifolius | Under Review | Wherever found | |
| Wireweed | Polygonella basiramia | Endangered | | 01-21-1987 |
| Wisconsin puma | Felis concolor schorgeri | Species of Concern | Wherever found | |
| Wisconsin well amphipod | Stygobromus putealis | Species of Concern | Wherever found | |
| Withered wooly milk-vetch | Astragalus mollissimus marcidus | Species of Concern | Wherever found | |
| Wolf's evening-primrose | Oenothera wolfii | Species of Concern | Wherever found | |
| Wolverine | Gulo gulo | Not Listed | | |
| wonder caddisfly | Neothremma prolata | Not Listed | | |
| Wonderland Alice-flower | Aliciella caespitosa | Resolved Taxon | Wherever found | |
| Wongs springsnail | Pyrgulopsis wongi | Species of Concern | Wherever found | |
| Wood Bison | Bison bison athabascae | Experimental Population, Non-Essential | U.S.A. (Alaska) | 05-07-2014 |
| Wood Bison | Bison bison athabascae | Threatened | Wherever found | 06-02-1970 |
| wood duck | Aix sponsa | Status Undefined | Wherever found | |
| Wood Frog | Lithobates sylvaticus | Status Undefined | Wherever found | |
| Woodhouse's Scrub-Jay | Aphelocoma woodhouseii | Species of Concern | | |
| Woodhouse's Scrub-Jay | Aphelocoma woodhouseii woodhouseii | Species of Concern | | |
| Woodland peperomia | Peperomia membranacea | Resolved Taxon | Wherever found | |
| Woodland vole | Microtus pinetorum | Status Undefined | Wherever found | |
| woodland woollythreads | Monolopia gracilens | Not Listed | | |
| Wood reedgrass | Calamagrostis perplexa | Species of Concern | Wherever found | |
| Wood River sculpin | Cottus leiopomus | Species of Concern | Wherever found | |
| Woodruff's ataenius dung beetle | Ataenius woodruffi | Species of Concern | Wherever found | |
| Wood stork | Mycteria americana | Threatened | U.S.A. (AL, FL, GA, MS, NC, SC) | 02-28-1984 |
| Wood Thrush | Hylocichla mustelina | Species of Concern | Wherever found | |
| Wood turtle | Glyptemys insculpta | Under Review | Wherever found | |
| Woodville Karst Cave crayfish | Procambarus orcinus | Resolved Taxon | Wherever found | |
| woolly rosette grass | Dichanthelium scabriusculum | Resolved Taxon | Wherever found | |
| Woolly seablite | suaeda taxifolia | Species of Concern | Wherever found | |
| Woolly spider monkey | Brachyteles arachnoides | Endangered | Wherever found | 06-02-1970 |
| Wooly berry | Vaccinium hirsutum | Species of Concern | Wherever found | |
| Wooly Gulf dune scarab | Polylamina pubescens | Species of Concern | Wherever found | |
| Wooly hydroporus diving beetle | Hydroporus hirsutus | Species of Concern | Wherever found | |
| Worm eating Warbler | Helmitheros vermivorum | Species of Concern | Wherever found | |
| Worn Stygobromid | Stygobromus tritus | Resolved Taxon | Wherever found | |
| Worthington's Marsh Wren | Cistothorus palustris griseus | Species of Concern | Wherever found | |
| Worthy Shield Lichen | Canoparmelia amabilis | Species of Concern | | |
| wounded darter | Etheostoma vulneratum | Species of Concern | Wherever found | |
| Woundfin | Plagopterus argentissimus | Endangered | Wherever found, except where listed as an experimental population | 10-13-1970 |
| Woundfin | Plagopterus argentissimus | Experimental Population, Non-Essential | Gila R. drainage, AZ, NM | 07-24-1985 |
| Wreathed cactus snail | Xerarionta redimita | Resolved Taxon | Wherever found | |
| Wrentit | Chamaea fasciata | Species of Concern | | |
| Wright fishhook cactus | Sclerocactus wrightiae | Endangered | Wherever found | 10-11-1979 |
| Wright's Dogweed | Adenophyllum wrightii | Resolved Taxon | Wherever found | |
| Wright's marsh thistle | Cirsium wrightii | Threatened | | 05-25-2023 |
| Wright's spiderwort | Tradescantia wrightii | Resolved Taxon | Wherever found | |
| Wright's trichocoronis | trichocoronis wrightii | Species of Concern | Wherever found | |
| Wright's water-willow | Justicia wrightii | Species of Concern | Wherever found | |
| Wright's yellowshow | Amoreuxia wrightii | Resolved Taxon | Wherever found | |
| Wupatki Arizona pocket mouse | Perognathus amplus cineris | Species of Concern | Wherever found | |
| Wyoming Dodder | Cuscuta plattensis | Resolved Taxon | Wherever found | |
| Wyoming pocket gopher | Thomomys clusius | Resolved Taxon | Wherever found | |
| Wyoming Toad | Anaxyrus baxteri | Endangered | Wherever found | 01-17-1984 |
| Xerces blue | Glaucopsyche xerces | Resolved Taxon | Wherever found | |
| XL Spring tui chub | Gila bicolor oregonensis | Species of Concern | Wherever found | |
| Yacare Caiman | Caiman yacare | Threatened | Wherever found | 06-02-1970 |
| Yadkin River Goldenrod | Solidago plumosa | Not Listed | | |
| Yadon's piperia | Piperia yadonii | Endangered | Wherever found | 08-12-1998 |
| Yalobusha Riverlet crayfish | Hobbseus yalobushensis | Under Review | Wherever found | |
| Yamaguchi phyllostegia | Phyllostegia yamaguchii | Resolved Taxon | Wherever found | |
| Yancey sideswimmer | Stygobromus carolinensis | Species of Concern | Wherever found | |
| Yangtze Sturgeon | Acipenser dabryanus | Endangered | Wherever found | 05-26-2021 |
| Yaqui catfish | Ictalurus pricei | Threatened | Wherever found | 08-31-1984 |
| Yaqui chub | Gila purpurea | Endangered | Wherever found | 08-31-1984 |
| Yaqui sucker | catostomus bernardini | Species of Concern | Wherever found | |
| Yarkand deer | Cervus elaphus yarkandensis | Endangered | Wherever found | 07-27-1979 |
| Yates' tight coin | Ammonitella yatesii | Species of Concern | Wherever found | |
| Yavapai Arizona cotton rat | Sigmodon arizonae jacksoni | Species of Concern | Wherever found | |
| Yavapai Arizona pocket mouse | Perognathus amplus amplus | Species of Concern | Wherever found | |
| Yavapai mountainsnail | Oreohelix yavapai | Species of Concern | Wherever found | |
| Yazoo crayfish | Orconectes hartfieldi | Resolved Taxon | Wherever found | |
| Yazoo darter | Etheostoma raneyi | Resolved Taxon | Wherever found | |
| Yazoo Shiner | Notropis rafinesquei | Not Listed | | |
| Yellow anisetree | Illicium parviflorum | Resolved Taxon | Wherever found | |
| Yellow-banded andrenid bee | Perdita hirticeps luteocincta | Species of Concern | Wherever found | |
| Yellow banded bumble bee | Bombus terricola | Resolved Taxon | Wherever found | |
| Yellow-bellied sapsucker | sphyrapicus varius | Species of Concern | Wherever found | |
| Yellow-billed Cuckoo | Coccyzus americanus | Threatened | Western DPS: U.S.A. (AZ, CA, CO (western), ID, MT (western), NM (western), NV, OR, TX (western), UT, WA, WY (western)); Canada (British Columbia (southwestern); Mexico (Baja California, Baja California Sur, Chihuahua, Durango (western), Sinaloa, Sonora) | 11-03-2014 |
| Yellow-billed Loon | Gavia adamsii | Resolved Taxon | Wherever found | |
| Yellow-billed Magpie | Pica nuttalli | Species of Concern | Wherever found | |
| Yellow-billed parrot | Amazona collaria | Threatened | Wherever found | 04-11-2013 |
| Yellow blanketflower | Gaillardia flava | Resolved Taxon | Wherever found | |
| Yellow bleedingheart | Dicentra ochroleuca | Resolved Taxon | Wherever found | |
| Yellow blossom (pearlymussel) | Epioblasma florentina florentina | Extinction | Wherever found; Except where listed as Experimental Populations | 06-14-1976 |
| Yellow blossom (pearlymussel) | Epioblasma florentina florentina | Resolved Taxon | U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a)) | 06-14-2001 |
| Yellow-blotched ensatina | Ensatina eschscholtzii croceator | Species of Concern | Wherever found | |
| Yellow-blotched map turtle | Graptemys flavimaculata | Threatened | Wherever found | 01-14-1991 |
| Yellow brachycercus mayfly | Brachycercus flavus | Species of Concern | Wherever found | |
| Yellow-breasted chat | icteria virens | Species of Concern | Wherever found | |
| Yellow-breasted Chat | Icteria virens virens | Species of Concern | | |
| Yellow-breasted Crake | Hapalocrex flaviventer hendersoni | Species of Concern | Wherever found | |
| Yellow-browed toucanet | Aulacorhynchus huallagae | Candidate | Wherever found | |
| Yellow Bullhead | Ameiurus natalis | Not Listed | | |
| Yellow-bur navarretia | Navarretia prolifera lutea | Resolved Taxon | Wherever found | |
| Yellow cedar | Callitropsis nootkatensis | Not Listed | | |
| Yellowcheek Darter | Etheostoma moorei | Endangered | Wherever found | 09-08-2011 |
| Yellow coneflower | Rudbeckia nitida nitida | Species of Concern | Wherever found | |
| Yellow-crested cockatoo | Cacatua sulphurea | Endangered | Wherever found | 06-24-2014 |
| yellow-eyed penguin | Megadyptes antipodes | Threatened | Wherever found | 09-02-2010 |
| yelloweye rockfish | Sebastes ruberrimus | Threatened | Puget Sound - Georgia Basin DPS See 50 CFR 223.102 | 04-13-2011 |
| Yellowfin cutthroat trout | Oncorhynchus clarkii macdonaldi | Resolved Taxon | Wherever found | |
| Yellowfin madtom | Noturus flavipinnis | Experimental Population, Non-Essential | U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.84(e)(1)(iii)) | 10-15-2007 |
| Yellowfin madtom | Noturus flavipinnis | Experimental Population, Non-Essential | U.S.A. (TN-specified portions of the Tellico River; see 17.84(e)(1)(ii)) | 08-12-2002 |
| Yellowfin madtom | Noturus flavipinnis | Experimental Population, Non-Essential | U.S.A. (TN, VA-specified portions of the Holston River and watershed; see 17.84(e)(1)(i)) | 08-04-1988 |
| Yellowfin madtom | Noturus flavipinnis | Threatened | Wherever found, except where listed as an experimental population | 10-11-1977 |
| Yellow-footed Gull | Larus livens | Species of Concern | | |
| Yellow-footed rock wallaby | Petrogale xanthopus | Endangered | Wherever found | 06-04-1973 |
| Yellow-foot yellow-faced bee | Hylaeus flavipes | Species of Concern | Wherever found | |
| Yellow-headed Blackbird | Xanthocephalus xanthocephalus | Species of Concern | | |
| Yellow lampmussel | Lampsilis cariosa | Species of Concern | Wherever found | |
| Yellow lance | Elliptio lanceolata | Threatened | Wherever found | 05-03-2018 |
| Yellow larkspur | Delphinium luteum | Endangered | Wherever found | 01-26-2000 |
| Yellow monitor | Varanus flavescens | Endangered | Wherever found | 06-14-1976 |
| Yellow mud turtle | Kinosternon flavescens flavescens | Species of Concern | Wherever found | |
| Yellow Mud Turtle | Kinosternon flavescens | Not Listed | | |
| Yellow-nosed cotton rat | Sigmodon ochrognathus | Species of Concern | Wherever found | |
| Yellow Perch | Perca flavescens | Not Listed | | |
| Yellow Pond lily | Nuphar lutea ssp. sagittifolia | Status Undefined | | |
| Yellow Rail | Coturnicops noveboracensis | Species of Concern | Wherever found | |
| Yellow Sandshell | Lampsilis teres | Not Listed | | |
| Yellow Shore Crab | Hemigrapsus oregonensis | Resolved Taxon | Wherever found | |
| Yellow-shouldered blackbird | Agelaius xanthomus | Endangered | Wherever found | 12-12-1976 |
| Yellow-sided clubtail | Stylurus potulentus | Under Review | Wherever found | |
| Yellow-spotted woodland salamander | Plethodon pauleyi | Under Review | | |
| Yellowstone cutthroat trout | Oncorhynchus clarkii bouvieri | Resolved Taxon | Wherever found | |
| Yellowstone Sand Verbena | Abronia ammophila | Resolved Taxon | Wherever found | |
| Yellow-tailed woolly monkey | Lagothrix flavicauda | Endangered | Wherever found | 10-19-1976 |
| Yellow-tubered toothwort | Cardamine nuttallii | Species of Concern | Wherever found | |
| Yellow warbler | dendroica petechia ssp. brewsteri | Species of Concern | Wherever found | |
| Yellow Warbler | Dendroica petechia gundlachi | Species of Concern | Wherever found | |
| Yellow-white catseye | Cryptantha ochroleuca | Resolved Taxon | Wherever found | |
| Yelm pocket gopher | Thomomys mazama yelmensis | Threatened | Wherever found | 05-09-2014 |
| Yerba de zanja | Ruppia anomala | Resolved Taxon | Wherever found | |
| Yoknapatawpha Darter | Etheostoma faulkneri | Not Listed | | |
| Yontocket saytr | Coenonympha tullia yontockett | Resolved Taxon | Wherever found | |
| Yorba Linda trigonoscuta weevil | Trigonoscuta yorbalindae | Resolved Taxon | Wherever found | |
| Yosemite bitterroot | Lewisia disepala | Resolved Taxon | Wherever found | |
| Yosemite mariposa sideband | Monadenia hillebrandi yosemitensis | Species of Concern | Wherever found | |
| Yosemite onion | Allium yosemitense | Resolved Taxon | Wherever found | |
| Yosemite toad | Anaxyrus canorus | Threatened | Wherever found | 06-30-2014 |
| Yosemite wooly-sunflower | Eriophyllum nubigenum | Species of Concern | Wherever found | |
| Young's snowbell | Styrax platanifolius ssp. youngiae | Species of Concern | Wherever found | |
| Yreka phlox | Phlox hirsuta | Endangered | Wherever found | 02-03-2000 |
| Yucaipa onion | allium haematochiton | Species of Concern | Wherever found | |
| Yukon aster | Symphyotrichum yukonense | Species of Concern | Wherever found | |
| Yukon Floater Mussel | Anodonta beringiana | Not Listed | | |
| Yuma brown towhee | Pipilo fuscus relictus | Resolved Taxon | Wherever found | |
| Yuma hispid cotton rat | Sigmodon hispidus eremicus | Species of Concern | Wherever found | |
| Yuma myotis | Myotis yumanensis | Species of Concern | Wherever found | |
| Yuman desert fringe-toed lizard | Uma rufopunctata | Under Review | Wherever found | |
| Yuma puma | Felis concolor browni | Species of Concern | Wherever found | |
| Yuma Ridgway's rail | Rallus obsoletus yumanensis | Endangered | Wherever found | 03-11-1967 |
| Yuma rufous-crowned sparrow | Aimophila ruficeps rupicola | Resolved Taxon | Wherever found | |
| Yunaska rock ptarmigan | Lagopus muta yunaskensis | Species of Concern | Wherever found | |
| Yunnan snub-nosed monkey | Rhinopithecus bieti | Endangered | Wherever found | 09-27-1990 |
| Zanzibar red colobus monkey | Procolobus (=Colobus) pennantii (=kirki) kirki | Endangered | Wherever found | 06-02-1970 |
| Zanzibar suni | Neotragus moschatus moschatus | Endangered | Wherever found | 07-27-1979 |
| Zapata bladderpod | Physaria thamnophila | Endangered | Wherever found | 11-22-1999 |
| Zarzarilla | Mimosa quadrivalvis var. urbaniana | Species of Concern | Wherever found | |
| Zayante band-winged grasshopper | Trimerotropis infantilis | Endangered | Wherever found | 01-24-1997 |
| Ziegler's aster | Machaeranthera canescens ziegleri | Resolved Taxon | Wherever found | |
| Ziegler's layia | Layia platyglossa | Species of Concern | Wherever found | |
| Zigzag blackwater caddisfly | Agarodes ziczac | Species of Concern | Wherever found | |
| Zion, coccineum wild-buckwheat | Eriogonum zionis coccineum | Resolved Taxon | Wherever found | |
| Zion tansy | Sphaeromeria ruthiae | Species of Concern | Wherever found | |
| Zion whitlow-grass | Draba asprella zionensis | Resolved Taxon | Wherever found | |
| Zion, zionis wild-buckwheat | Eriogonum zionis zionis | Resolved Taxon | Wherever found | |
| Zuni bluehead Sucker | Catostomus discobolus yarrowi | Endangered | Wherever found | 08-25-2014 |
| Zuni fleabane | Erigeron rhizomatus | Threatened | Wherever found | 04-26-1985 |