Astragalus rattanii var. jepsonianus
Jepson's milkvetch
(c) Steve Matson, some rights reserved (CC BY), uploaded by Steve Matson · licence
Family: Fabaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Astragalus rattanii var. jepsonianus (Jepson's milkvetch) is a native California herb in the Fabaceae family, recognized by distinctive flower coloration and narrow linear fruits diagnostic.
Jepson's milkvetch is a rare (CNPS 1B.2) California native annual found in southern North Coast Ranges Interior and central eastern South Coast Ranges Interior, specifically at the northern edge of the New Idria serpentine mass, in grasslands and woodland openings at elevations of 150 to 700 meters. Flowering from April to June, this plant produces white flowers with a distinctive purple-tipped banner, clustered in small groups of 4 to 9 blossoms. Growing as a delicate annual with slender stems, it develops low to the ground in serpentine and vertic clay environments. Its compound leaves feature 7 to 9 leaflets, creating a fine, intricate foliage pattern typical of milkvetches. The plant's adaptation to serpentine soils and its subtle flower coloration make it a unique component of California's grassland ecosystems.
Identification and appearance
Key characters: 5 sympatric species; distinctive flower coloration and narrow linear fruits diagnostic
Habitat and range
Habitat: Grasslands, grassy openings in woodland and chaparral, vertic clay, often serpentine
Elevation: 150-700 m
California counties: Lake, Colusa, Napa, Glenn, Tehama, San Benito, San Bernardino
Bloom period
Astragalus rattanii var. jepsonianus blooms Apr-Jun.
Conservation status
CNPS 1B.2
How to tell it apart
vs Vicia: Astragalus has racemes of flowers; vetches (Vicia) have tendrils at leaf tips and climbing or sprawling habit.; vs Oxytropis: Astragalus keel tip is rounded to slightly pointed; Oxytropis keel has a pronounced pointed beak.; vs Cleomella: Astragalus has pea-shaped flowers; Cleomella has 4-petaled cruciform flowers with long stamens.; vs Lupinus: Astragalus has pinnate compound leaves; lupines have palmate leaves (leaflets radiating from one point).; vs Dalea: Astragalus has typical pea flowers; Dalea has tiny flowers with petals attached to the stamen tube.
Frequently asked questions
Is Astragalus rattanii var. jepsonianus native to California?
Yes. Astragalus rattanii var. jepsonianus is native to California (recorded as native).
When does Astragalus rattanii var. jepsonianus bloom?
Astragalus rattanii var. jepsonianus blooms Apr-Jun.
Where in California does Astragalus rattanii var. jepsonianus grow?
Astragalus rattanii var. jepsonianus occurs in Lake, Colusa, Napa, Glenn, Tehama, San Benito, San Bernardino, at elevations of 150-700 m.
What plant family does Astragalus rattanii var. jepsonianus belong to?
Astragalus rattanii var. jepsonianus is in the Fabaceae family, genus Astragalus.
Is Astragalus rattanii var. jepsonianus rare or endangered?
Astragalus rattanii var. jepsonianus carries California Rare Plant Rank 1B.2, state rank S3.
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.