Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to California, scattered eastward across much of North America.
Habitat: Waste ground and disturbed areas, mostly at low elevations.
Flowers: March-June
Origin: Introduced
Growth Duration: Annual, Perennial
Conservation Status: Not of concern
Pollination: Bees, butterflies
Usually glabrous annual, the stems 1-4 dm. long, prostrate to nearly erect.
Leaves trifoliate, the leaflets obovate or obcordate with a wedge-shaped base, 1-1.5 cm, long, not spotted, denticulate at the apex; stipules lacerated for over half their width.
Flowers 2-5 on fairly short peduncles arising from the leaf axils; calyx 3 mm. long, the 5 teeth slightly longer than the tube; corolla pea-like, yellow, 4-5 mm. long, the banner erect, much longer than the wings and keel.
Pod spirally coiled, the margins narrowly keeled, spineless, or with two rows of divergent prickles up to 3 mm. long.
PNW Herbaria: Specimen records of Medicago polymorpha in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Medicago polymorpha checklist entry
OregonFlora: Medicago polymorpha information
E-Flora BC: Medicago polymorpha atlas page
CalPhotos: Medicago polymorpha photos