Taxon Report
Hesperolinon congestum (Gray) SmallMarin western flax |
 © 2009 Neal Kramer |
Taxon Summary
Hesperolinon congestum, commonly known as Marin western flax, is a annual herb in the Linaceae that is found only in California. It occurs within Chaparral, and Valley and foothill grassland, growing at elevations from 5 to 370 meters. Hesperolinon congestum is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Hesperolinon congestum (Gray) Small |
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Common Name: |
Marin western flax |
| Family: | Linaceae |
| Element Code: | PDLIN01060 |
| USDA Plants Symbol: | HECO12 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb |
| Blooming Period: Apr-Jul | Apr-Jul |
| Elevation: | 5-370 (15-1215) |
| General Habitats: | Chaparral, Valley and foothill grassland |
| Microhabitat: | Serpentine |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.1 |
| Global Rank: | G1 |
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State Rank: |
S1 |
| State List: | CT |
| Fed List: | FT |
| Other Status: | SB_CalBG/RSABG; SB_UCBG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 27 |
| Element Occurrence Ranks: | |
| Excellent (A) | 4 |
| Good (B) | 10 |
| Fair (C) | 5 |
| Poor (D) | 1 |
| None (X) | 3 |
| Unknown (U) | 4 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Marin (MRN), San Francisco (SFO), San Mateo (SMT) | |
| Quads: Name (Quad Code) | |
| Bolinas (3712286), Novato (3812215), Palo Alto (3712242), Petaluma (3812226), Petaluma River (3812225), San Francisco North (3712274), San Geronimo (3812216), San Mateo (3712253), San Quentin (3712284), San Rafael (3712285), Woodside (3712243) | |
Threat List Data from the CNDDB
| Threat List Total: | 12 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 21 | 78 % | |
| Non-native plant impacts | 13 | 48% |
| Foot traffic/trampling | 12 | 44% |
| Road/trail construction/maint. | 11 | 40% |
| Development | 7 | 25% |
| Erosion/runoff | 5 | 18% |
| Recreational use (non-ORV) | 5 | 18% |
| Other | 4 | 14% |
| Grazing | 2 | 7% |
| Biocides | 2 | 7% |
| Dam/Inundation | 2 | 7% |
| Vandalism/dumping/litter | 2 | 7% |
| Disking | 1 | 3% |
Notes
| Protected in part at Ring Mtn. Preserve, MRN Co. Threatened by development, non-native plants, and foot traffic. Potentially threatened by hydrological alterations. See Proceedings of the American Academy of Arts and Sciences 6:521 (1865) for original description, and University of California Publications in Botany 32:235-314 (1961) 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 27 October 2025].