Taxon Report
Chorizanthe howellii Goodm.Howell's spineflower |
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Taxon Summary
Chorizanthe howellii, commonly known as Howell's spineflower, is a annual herb in the Polygonaceae that is found only in California. It occurs within Coastal dunes, Coastal prairie, and Coastal scrub, growing at elevations from 0 to 45 meters. Chorizanthe howellii is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Chorizanthe howellii Goodm. |
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Common Name: |
Howell's spineflower |
| Family: | Polygonaceae |
| Element Code: | PDPGN040C0 |
| USDA Plants Symbol: | CHHO2 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb |
| Blooming Period: May-Jul | May-Jul |
| Elevation: | 0-45 (0-150) |
| General Habitats: | Coastal dunes, Coastal prairie, Coastal scrub |
| Microhabitat: | Disturbed areas (often), Sandy |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.2 |
| Global Rank: | G1 |
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State Rank: |
S1 |
| State List: | CT |
| Fed List: | FE |
| Other Status: | |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 9 |
| Element Occurrence Ranks: | |
| Excellent (A) | 0 |
| Good (B) | 6 |
| Fair (C) | 0 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 3 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Mendocino (MEN) | |
| Quads: Name (Quad Code) | |
| Fort Bragg (3912347), Inglenook (3912357), Mendocino (3912337) | |
Threat List Data from the CNDDB
| Threat List Total: | 8 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 8 | 89 % | |
| Foot traffic/trampling | 5 | 55% |
| Other | 5 | 55% |
| Recreational use (non-ORV) | 4 | 44% |
| Non-native plant impacts | 3 | 33% |
| Development | 2 | 22% |
| Road/trail construction/maint. | 2 | 22% |
| Erosion/runoff | 1 | 11% |
| ORV activity | 1 | 11% |
Notes
| Known only from north of Ft. Bragg. Threatened by development, foot traffic, recreational activities, vehicles, and non-native plants. Potentially threatened by trail construction. Closely related to C. pungens. See Annals of the Missouri Botanical Garden 21:44 (1934) for original description, and Phytologia 66(2):131-132 (1989) for taxonomic treatment. |
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Threats: |
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Taxonomy: |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 20 November 2025].