Taxon Report
Howellia aquatilis Graywater howellia |
 ©2018 John Doyen |
Taxon Summary
Howellia aquatilis, commonly known as water howellia, is a annual herb (aquatic) in the Campanulaceae that is found in California and elsewhere. It occurs within Marshes and swamps, growing at elevations from 1085 to 1290 meters. Howellia aquatilis is ranked 2B.2, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Howellia aquatilis Gray |
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Common Name: |
water howellia |
| Family: | Campanulaceae |
| Element Code: | PDCAM0A010 |
| USDA Plants Symbol: | HOAQ |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb (aquatic) |
| Blooming Period: Jun | Jun |
| Elevation: | 1085-1290 (3560-4230) |
| General Habitats: | Marshes and swamps |
| Microhabitat: | |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 2B.2 |
| Global Rank: | G3 |
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State Rank: |
S2 |
| State List: | None |
| Fed List: | FD |
| Other Status: | |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 7 |
| Element Occurrence Ranks: | |
| Excellent (A) | 2 |
| Good (B) | 2 |
| Fair (C) | 1 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 2 |
| California Endemic: False | |
| California Counties and Islands: Name (Code) | |
| Humboldt (HUM), Mendocino (MEN), Trinity (TRI) | |
| Quads: Name (Quad Code) | |
| Alderpoint (4012325), Black Lassic (4012335), Buck Rock (3912288), Fort Seward (4012326), Leech Lake Mtn. (3912381) | |
Threat List Data from the CNDDB
| Threat List Total: | 3 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 3 | 43 % | |
| Foot traffic/trampling | 1 | 14% |
| Non-native plant impacts | 1 | 14% |
| Other | 1 | 14% |
Notes
| Federally listed as threatened on 1994-08-15; Delisted due to Recovery on 2021-07-16. Rediscovered in CA in 1996 by D. Isle and D. Efseaff. Previously known in CA from only a single collection near Howard Lake in 1928; where possibly extirpated by cattle grazing and trampling. Endangered in ID and OR, and state-listed as Threatened in WA. |
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Threats: |
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Threatened by hydrological alteration, grazing, and trampling. |
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Taxonomy: |
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Inadvertently omitted from The Jepson Manual. |
Selected References
| Proceedings of the American Academy of Arts and Sciences 15:43 (1879) |
| Howellia aquatilis profile for potential Species of Conservation Concern evaluation (2018) |
| Recovery Plan for Howellia aquatilis (water howellia) (USFWS 1996) |
| Wasmann Journal of Biology 33:90-91 (1975) [CA record] |
| Conservation Biology 2(3):275-282 (1988) [Ecological information] |
| Fremontia 25:3 (1997) [Account of rediscovery] |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 2 November 2025].