Water howellia (Howellia aquatilis)
Where Listed: WHEREVER FOUND
Water howellia (Howellia aquatilis) is a winter annual aquatic plant that grows 4-24 inches high. It has extensively branched, submerged or floating stems and narrow, linear, alternate (sometimes opposite) leaves up to 2 inches in length. Water howellia usually flowers in May and June, with small trumpet-shaped blooms ranging from white to light purple in color, at or above the water surface. There may also be small axillary flowers beneath the water surface. Water howellia reproduces only by seed which germinates when ponds dry during fall. This results in annual variability in population size depending on the extent of the previous season’s drying. Flowering occurs from June to August. The plant grows in areas that were once associated with glacial potholes and former river oxbows that flood in the spring, but usually dry at least partially by late summer. It is often found in shallow water (1-2 meters) and on the edges of deep ponds that are partially surrounded by deciduous trees such as black cottonwood and aspen. States in which Howellia aquatilis is known to occur: Currently known from California, Idaho, Montana, and Washington. Historically found in Oregon. The plant has also been found on Turnbull National Wildlife Refuge in Washington.
- States/US Territories in which the Water howellia is known to or is believed to occur: California , Idaho , Montana , Oregon , Washington
- US Counties in which the Water howellia is known to or is believed to occur: View All
- USFWS Refuges in which the Water howellia is known to occur:
Ridgefield National Wildlife Refuge, Swan Valley Conservation Area, Turnbull National Wildlife Refuge
|Status||Date Listed||Lead Region||Where Listed|
|07/14/1994||Mountain-Prairie Region (Region 6)|
» Federal Register Documents
|04/16/1993||58 FR 19795 19800||ETWP; Proposed Listing of Water Howellia (Howellia aquatilis) as Threatened|
|07/14/1994||59 FR 35860 35864||ETWP; The Plant, Water Howellia (Howellia Aquatilis), Determined to Be a Threatened Species|
|04/18/2007||72 FR 19549 19551||Initiation of 5-Year Reviews of Seven Wildlife Species and Two Plant Species in the Mountain-Prairie Region|
|Date||Title||Plan Action Status||Plan Status|
|09/24/1996||Water Howellia (Howellia aquatilis) Recovery Plan, Public and Agency Review Draft||View Implementation Progress||Draft|
|Date||Citation Page||Title||Document Type|
|04/18/2007||72 FR 19549 19551||Initiation of 5-Year Reviews of Seven Wildlife Species and Two Plant Species in the Mountain-Prairie Region||
|08/30/2013||Water howellia (Howellia aquatilis) 5-Year Review|
» Critical Habitat
No critical habitat rules have been published for the Water howellia.
» Conservation Plans
No conservation plans have been created for Water howellia.
» Life History
No Life History information has been entered into this system for this species.
» 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.