Taxon Report
Lasthenia conjugens GreeneContra Costa goldfields |
 © 2013 Neal Kramer |
Taxon Summary
Lasthenia conjugens, commonly known as Contra Costa goldfields, is a annual herb in the Asteraceae that is found only in California. It occurs within Cismontane woodland, Playas (alkaline), Valley and foothill grassland, and Vernal pools, growing at elevations from 0 to 470 meters. Lasthenia conjugens is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Lasthenia conjugens Greene |
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Common Name: |
Contra Costa goldfields |
| Family: | Asteraceae |
| Element Code: | PDAST5L040 |
| USDA Plants Symbol: | LACO6 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb |
| Blooming Period: Mar-Jun | Mar-Jun |
| Elevation: | 0-470 (0-1540) |
| General Habitats: | Cismontane woodland, Playas, Valley and foothill grassland, Vernal pools |
| Microhabitat: | Mesic |
| 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: | FE |
| Other Status: | SB_UCBG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 36 |
| Element Occurrence Ranks: | |
| Excellent (A) | 2 |
| Good (B) | 12 |
| Fair (C) | 1 |
| Poor (D) | 0 |
| None (X) | 11 |
| Unknown (U) | 10 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Alameda (ALA), Contra Costa (CCA), Marin (MRN), Mendocino (MEN)*, Monterey (MNT), Napa (NAP), Santa Barbara (SBA)*, Santa Clara (SCL)*, Solano (SOL), Sonoma (SON) | |
| Quads: Name (Quad Code) | |
| Antioch North (3812117), Antioch South (3712187), Benicia (3812212), Capell Valley (3812242)*, Cuttings Wharf (3812223), Denverton (3812128), Dos Pueblos Canyon (3411948), Elmira (3812138), Fairfield North (3812231), Fairfield South (3812221), Goleta (3411947)*, Marina (3612167), Milpitas (3712148), Napa (3812233), Newark (3712251)*, Petaluma River (3812225), Point Arena (3812386)*, Salinas (3612166), San Jose East (3712137)*, San Leandro (3712262), Seaside (3612157), Valley Ford (3812238), Walnut Creek (3712281)* | |
Threat List Data from the CNDDB
| Threat List Total: | 14 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 25 | 69 % | |
| Development | 13 | 36% |
| Grazing | 8 | 22% |
| Non-native plant impacts | 7 | 19% |
| Disking | 4 | 11% |
| Agriculture | 3 | 8% |
| Other | 3 | 8% |
| Feral pigs | 2 | 5% |
| Altered flood/tidal/hydrologic regime | 2 | 5% |
| ORV activity | 2 | 5% |
| Landfill | 1 | 2% |
| Military operations | 1 | 2% |
| Erosion/runoff | 1 | 2% |
| Recreational use (non-ORV) | 1 | 2% |
| Wood cutting or brush clearing | 1 | 2% |
Notes
| Many historical occurrences extirpated by development and agriculture. Currently threatened by development, habitat alteration, hydrological alterations, overgrazing, and non-native plants. See Pittonia 1:221 (1888) for original description, and Madroño 50(2):83-93 (2003) for ecological information. |
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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 6 November 2025].