Page authors: Don Knoke, David Giblin
Medicago polymorpha
bur-clover, toothed medic, smooth medic

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.

Accepted Name:
Medicago polymorpha L.
Publication: Fl. Carniol. (ed. 2) 2: 89. 1772.

Synonyms & Misapplications:
Medicago apiculata Willd.
Medicago hispida Gaertn. [HC]
Medicago hispida Gaertn. var. apiculata (Willd.) Burnat
Medicago hispida Gaertn. var. confinis (W.D.J. Koch) Burnat
Medicago polymorpha L. var. brevispina (Benth.) Heyn
Medicago polymorpha L. var. ciliaris (Ser.) Shinners
Medicago polymorpha L. var. polygyra (Urb.) Shinners
Medicago polymorpha L. var. tricycla (Gren. & Godr.) Shinners
Medicago polymorpha L. var. vulgaris (Benth.) Shinners
Additional Resources:

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

16 photographs:
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