Lasthenia conjugens
Contra costa goldfields, Contra Costa Goldfields
no rights reserved · CC0
Family: Asteraceae · Type: Herb · Native
Conservation status: CNPS 1B.1 · Endangered
Lasthenia conjugens (Contra costa goldfields) is a native California herb in the Asteraceae family, recognized by club-shaped fruits lacking pappus and densely hairy receptacle.
Contra costa goldfields is a rare (CNPS 1B.1) California native annual found in southern Sacramento Valley (Napa and Solano counties), Central Coast, San Francisco Bay Area, and historically in northern coastal regions in vernal pools and wet meadows at elevations below 100 meters. Flowering from March to June, this plant produces bright yellow flowers in small heads with 6 to 13 ray flowers, each ray 5 to 10 millimeters long. Growing up to 40 centimeters tall with stems that are either simple or freely branched and glabrous or slightly hairy, it develops delicate linear leaves less than 8 centimeters long. Its leaves are entire or occasionally pinnately lobed, with an intricate involucre 6 to 10 millimeters wide featuring 12 to 18 hairy phyllaries that persist through flowering. The tiny fruits are club-shaped and less than 1.5 millimeters long, with no pappus present.
Identification and appearance
Key characters: 17 sympatric species; club-shaped fruits lacking pappus and densely hairy receptacle
Habitat and range
Habitat: Vernal pools, wet meadows
Elevation: < 100 m
Bloom period
Lasthenia conjugens blooms Mar-Jun.
Conservation status
CNPS 1B.1 · Endangered
How to tell it apart
vs Monolopia: Monolopia has alternate leaves; Lasthenia has opposite leaves throughout most of stem.; vs Eriophyllum: Eriophyllum is woolly-hairy; Lasthenia is smooth or only slightly hairy.; vs Ranunculus: Ranunculus has separate shiny petals and divided basal leaves; Lasthenia has composite flower heads.; vs Pseudobahia: Pseudobahia leaves are alternate above; Lasthenia leaves remain opposite throughout.; vs Blennosperma: Blennosperma has phyllaries fused into a cup; Lasthenia has separate overlapping phyllaries.
Frequently asked questions
Is Lasthenia conjugens native to California?
Yes. Lasthenia conjugens is native to California (recorded as native).
When does Lasthenia conjugens bloom?
Lasthenia conjugens blooms Mar-Jun.
What plant family does Lasthenia conjugens belong to?
Lasthenia conjugens is in the Asteraceae family, genus Lasthenia.
Is Lasthenia conjugens rare or endangered?
Lasthenia conjugens carries California Rare Plant Rank 1B.1, state rank S1.
What habitat does Lasthenia conjugens grow in?
Lasthenia conjugens grows in Vernal pools, wet meadows.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.