Walker's manioc (Manihot walkerae)
Where Listed: WHEREVER FOUND
Walker’s manioc, a member of the spurge family (Euphorbiacea), is a spindly, almost vine-like perennial herb.
- States/US Territories in which the Walker's manioc, Wherever found is known to or is believed to occur: Texas
- US Counties in which the Walker's manioc, Wherever found is known to or is believed to occur: View All
- USFWS Refuges in which the Walker's manioc, Wherever found is known to occur:
Lower Rio Grande Valley National Wildlife Refuge, Santa Ana National Wildlife Refuge
- Countries in which the the Walker's manioc, Wherever found is known to occur: Mexico
- Additional species information
|Status||Date Listed||Lead Region||Where Listed|
|1991-10-02||Southwest Region (Region 2)||Wherever found|
» Federal Register Documents
|1990-10-01 00:00:00.0||55 FR 39989 39992||ETWP; Proposed Rule to List the Plant Manihot walkerae (Walker's manioc) as Endangered; 55 FR 39989 39992|
|1991-10-02 00:00:00.0||56 FR 49850 49854||ETWP; Final Rule to List the Plant Manihot walkerae as Endangered; 56 FR 49850 49854|
|2007-04-23 00:00:00.0||72 FR 20134 20136||5-Year Reviews of 24 Southwestern Species|
|2015-04-15 00:00:00.0||80 FR 20241 20243||Endangered and Threatened Wildlife and Plants; 5-Year Status Reviews of Black-Lace Cactus, Bone Cave Harvestman, Pima Pineapple Cactus, Texas Snowbells, and Walker’s Manioc in the Southwest Region (Notice of initiation of reviews; request for information.|
|Date||Title||Plan Action Status||Plan Status|
|1993-12-12||Walker's Manioc (Manihot walkerae) Recovery Plan||View Implementation Progress||Final|
|Date||Citation Page||Title||Document Type|
|2015-04-15||80 FR 20241 20243||Endangered and Threatened Wildlife and Plants; 5-Year Status Reviews of Black-Lace Cactus, Bone Cave Harvestman, Pima Pineapple Cactus, Texas Snowbells, and Walker’s Manioc in the Southwest Region (Notice of initiation of reviews; request for information.||
|2007-04-23||72 FR 20134 20136||5-Year Reviews of 24 Southwestern Species||
|2009-06-04||Walker's Manioc Completed 5-Yr Review|
» Critical Habitat
No critical habitat rules have been published for the Walker's manioc.
» Conservation Plans
No conservation plans have been created for Walker's manioc.
» Life History
Walker’s manioc usually grows among low shrubs, native grasses and herbaceous plants, either in full sunlight, or in partial shade of shrubs. Woody associates of Walker’s manioc, include calderona (Krameria ramosissima), blackbrush acacia (Acacia rigidula), cenizo (Leucophyllum frutescens), Mission fiddlewood (Citharexylum spathulatum), coyotillo (Karwinskia humboldtiana), and tasajillo (Opuntia leptocaulis). Other plants that grow in association with Walker’s manioc include anacahuita (Cordia boissieri), barreta (Helietta parvifolia), blue sage (Salvia ballotaeflora), drago (Jatropha dioica), elbowbush (Forestiera angustifolia), guayacan (Guaiacum angustifolium), oregano cimarron (Lippia graveolens), and colima (Zanthoxylum fagara).
Walker’s manioc is found in sandy, calcareous soil, shallowly overlying caliche and conglomerate of the Goliad Formation on rather xeric slopes and uplands.
Movement / Home Range
Walker’s manioc populations occur in Starr and Hidalgo counties, Texas. Populations also occur in northeast Mexico.
Male flowers are about ˝ inch (1.3 centimeters) long, white with light purple streaks and almost tubular in shape. The 3/8 inch (0.95 centimeters) long female flowers occur at the base of the male flower stalks. The fruit is a dry, globular capsule about ˝ inch long (1.3 centimeters), occur on slightly downward curved stalks and contain three seeds. The seeds are round or slightly flattened and gray with small irregular dark spots.
The plants can reach up to six feet (1.83 meters) in height. The leaves have up to five lobes that may be shallowly or deeply indented. The narrow stems are smooth and grayish brown. The tuberous roots of the Walker’s manioc measure up to ten inches in length and four inches in width and resemble carrots or turnips.
» Other Resources
NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.