Taxon Report
Isocoma arguta GreeneCarquinez goldenbush |
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Taxon Summary
Isocoma arguta, commonly known as Carquinez goldenbush, is a perennial shrub in the Asteraceae that is found only in California. It occurs within Valley and foothill grassland, growing at elevations from 1 to 20 meters. Isocoma arguta is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Isocoma arguta Greene |
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Common Name: |
Carquinez goldenbush |
| Family: | Asteraceae |
| Element Code: | PDAST57050 |
| USDA Plants Symbol: | ISAR2 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial shrub |
| Blooming Period: Aug-Dec | Aug-Dec |
| Elevation: | 1-20 (5-65) |
| General Habitats: | Valley and foothill grassland |
| Microhabitat: | |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.1 |
| Global Rank: | G1 |
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State Rank: |
S1 |
| State List: | None |
| Fed List: | None |
| Other Status: | SB_UCBG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 14 |
| Element Occurrence Ranks: | |
| Excellent (A) | 0 |
| Good (B) | 4 |
| Fair (C) | 3 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 7 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Contra Costa (CCA), Solano (SOL) | |
| Quads: Name (Quad Code) | |
| Benicia (3812212), Birds Landing (3812127), Briones Valley (3712282), Cordelia (3812222), Denverton (3812128), Dozier (3812137), Elmira (3812138), Mare Island (3812213), Vine Hill (3812211), Walnut Creek (3712281) | |
Threat List Data from the CNDDB
| Threat List Total: | 7 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 8 | 57 % | |
| Grazing | 3 | 21% |
| Road/trail construction/maint. | 3 | 21% |
| Other | 1 | 7% |
| Recreational use (non-ORV) | 1 | 7% |
| Agriculture | 1 | 7% |
| Biocides | 1 | 7% |
| Development | 1 | 7% |
Notes
| Threatened by grazing and trampling at Jepson Prairie Preserve. Treatened by development and agriculture elsewhere. See Manual of the Botany of the Region of San Francisco Bay, p. 175 (1894) by E. Greene for original description, and Phytologia 70(2):69-114 (1991) 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 3 September 2025].