Astragalus obscurus
Arcane milkvetch
(c) Steve Matson, some rights reserved (CC BY), uploaded by Steve Matson · licence
Family: Fabaceae · Type: Herb · Native
Astragalus obscurus (Arcane milkvetch) is a native California herb in the Fabaceae family, recognized by low mat-forming habit and thick leaflets.
Arcane milkvetch is a California native perennial found in the southeastern Klamath Ranges, Cascade Range, and Modoc Plateau in rocky basalt and granite habitats at elevations of 800 to 2,150 meters. Flowering from May to July, this plant produces cream or dirty white flowers with a lilac tinge, with banner petals recurved at about 45 degrees. Growing with prostrate or tufted stems less than 15 centimeters tall and widely branched, it forms low, spreading clusters. Its leaves are 2.5 to 10 centimeters long, composed of 5 to 15 narrowly to widely elliptic leaflets that are 2 to 15 millimeters long and slightly thick. The fruit is an erect, linear-oblong pod 10 to 25 millimeters long, finely hairy and leathery with a thickened upper suture.
Identification and appearance
Key characters: 34 sympatric species; key features are low mat-forming habit and thick leaflets
Habitat and range
Habitat: Rocky, basalt, granite
Elevation: 800-2150 m
California counties: Siskiyou, Modoc, Lassen, Trinity
Outside California: to Oregon, Idaho, Nevada
Bloom period
Astragalus obscurus blooms May-Jul.
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 obscurus native to California?
Yes. Astragalus obscurus is native to California (recorded as native).
When does Astragalus obscurus bloom?
Astragalus obscurus blooms May-Jul.
Where in California does Astragalus obscurus grow?
Astragalus obscurus occurs in Siskiyou, Modoc, Lassen, Trinity, at elevations of 800-2150 m.
What plant family does Astragalus obscurus belong to?
Astragalus obscurus is in the Fabaceae family, genus Astragalus.
What habitat does Astragalus obscurus grow in?
Astragalus obscurus grows in Rocky, basalt, granite.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
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.