Howellia

{{Short description|Genus of flowering plants}} {{Speciesbox |image = Howelliaaquatilis.jpg |status = G3 |status_system=TNC |status_ref=<ref>{{cite web|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.136199/Howellia_aquatilis|title=''Howellia aquatilis''|author=NatureServe|publisher=NatureServe|location=Arlington, Virginia|website=NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer|access-date=3 April 2023|date=3 March 2023}}</ref> |status2 = DL |status2_system = ESA |status2_ref = <ref name=fr86>{{Federal Register|86|31955}}</ref> |display_parents = 2 |genus = Howellia |parent_authority = A.Gray |species = aquatilis |authority = A.Gray }}

'''''Howellia aquatilis''''', the '''water howellia''', is a small plant in the family Campanulaceae that was considered a federally threatened species between 1994<ref>{{Federal Register|59|35860}}</ref> and 2021 under the Endangered Species Act of 1973.<ref name=fr86/><ref>{{Cite web|url=https://www.federalregister.gov/documents/2019/10/07/2019-21645/endangered-and-threatened-wildlife-and-plants-removal-of-howellia-aquatilis-water-howellia-from-the|title=Endangered and Threatened Wildlife and Plants; Removal of Howellia aquatilis (Water Howellia) From the List of Endangered and Threatened Plants|date=2019-10-07|website=Federal Register|access-date=2019-10-06}}</ref> It is the only species in the monotypic genus '''''Howellia'''''.<ref name=cpc>{{Cite web |url=http://www.centerforplantconservation.org/collection/cpc_viewprofile.asp?CPCNum=2278 |title=Center for Plant Conservation. |access-date=2011-04-16 |archive-url=https://web.archive.org/web/20110807124520/http://www.centerforplantconservation.org/collection/cpc_viewprofile.asp?CPCNum=2278 |archive-date=2011-08-07 |url-status=dead }}</ref> Thomas Jefferson Howell and Joseph Howell discovered the species in 1878.<ref name=Companion>{{cite book |last= Engeman |first= Richard H. |title= The Oregon Companion: An Historical Gazetteer of The Useful, The Curious, and The Arcane |year= 2009 |publisher= Timber Press |location= Portland, Oregon |isbn= 978-0-88192-899-0 |page= 184}}</ref>

==Distribution== The water howellia is found in large area of the Pacific Northwest region of the United States. It can be found in California, Idaho, Montana, and Washington, and it is known historically from Oregon.<ref name=fed>[http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=Q2RM USFWS Species Profile.]</ref>

The plant grows in wetland habitat surrounded by forests, which provide organic material.<ref name=cpc/> Associated tree species include ''Populus trichocarpa'' (California poplar), ''P. tremuloides'' (quaking aspen), and ''Fraxinus latifolia'' (Oregon ash).<ref name=cpc/> The water bodies are located in glacial potholes, river oxbows, ephemeral ponds, flood plains and other areas that fill with water periodically as snow melts and spring rain falls.<ref name=cpc/>

==Biology== The plant produces two types of flowers. Submerged cleistogamous flowers remain closed and self-pollinate, and flowers that bloom above the surface of the water open into white blossoms and may cross with other individuals.<ref name=cpc/> Because it often pollinates itself, the species has a low genetic diversity.<ref name=cpc/> Seeds are produced in the water but they require open air for germination, so they sprout when the wetland has dried in the fall.<ref name=cpc/>

==Conservation== Threats to this species include loss of habitat to logging and draining and conversion to urban use, alteration of the local hydrology by placement of dams and dikes, deposition of silt, livestock activity, introduced species of plants, low genetic diversity, and climate change.<ref name=fs>[http://www.fs.fed.us/wildflowers/rareplants/profiles/tep/howellia_aquatilis/index.shtml USFS Wildflowers.]</ref>

==References== {{Reflist}}

==External links== *[https://plants.usda.gov/cgi_bin/topics.cgi?earl=plant_profile.cgi&symbol=HOAQ USDA Plants Profile]

Category:Lobelioideae Category:Monotypic Campanulaceae genera