Taxon Report
Isocoma arguta GreeneCarquinez goldenbush |
 © 2010 Doug Wirtz |
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
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Threats: |
| Threatened by grazing and trampling at Jepson Prairie Preserve. Threatened by development and agriculture elsewhere. |
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Taxonomy: |
| 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. |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 24 October 2025].