Frequent throughout the state along railroads and roadsides and in lawns, waste places, and fields. It was probably mostly introduced in clover seed and lawn grass seed.
Kearney and Peebles 1969, McDougall 1973
Duration: Annual Nativity: Non-Native Lifeform: Forb/Herb General: Herbaceous annuals or perennials, to 60 cm tall, stems several, prostrate to decumbent or ascending, branching from the base, herbage pubescent to finely strigose. Leaves: Alternate, pinnately trifoliate, leaflets obovate to suborbicular, 6-15 mm long, margins denticulate, at least on the upper half, stipules lance-ovate, entire or few-toothed, petioles 2-15 mm long. Flowers: Yellow, very small, with banner, wing, and keel petals (papilionaceous), 2 mm long or less, keel petal shorter than the wing or banner petals, calyx tube campanulate with subequal teeth, villous, stamens diadelphous (9 fused, 1 free), flowers numerous, borne in ovoid, spike-like racemes, these becoming oblong in fruit, peduncles 10-25 mm long, (usually exceeding the leaves). Fruits: Pods kidney-shaped, 1-2 mm long, coiled in 1 plane, strongly veined, black when ripe, surfaces glabrous, not prickly. Seeds 1 per pod. Ecology: Found in disturbed areas, roadsides, and lawns, from 2,500-8,000 ft (762-2438 m); flowering March-September. Distribution: Widespread throughout North America. Notes: The tiny yellow flowers and kidney-shaped, unarmed seed pods coiled in 1 plane help identify this species. Naturalized from Europe. Ethnobotany: There is no use recorded for this species, but other species in this genus have uses. Etymology: Medicago is derived from Medike, or medick, the Greek name for alfalfa, which came to Greece from Medea, while lupulina means hop-like. Synonyms: Medica lupulina Editor: LCrumbacher 2012
Annual or biennial with prostrate or ascending stems to 8 dm; stipules lanceolate, entire or toothed; lfls elliptic to obovate, 1-2 cm; peduncles much exceeding the subtending lvs; heads globose to short-cylindric, to 1 cm; fls yellow, 10-50 per head, 2-4 mm; pods nearly black, 2-3 mm, reniform, unarmed, 1-seeded, the conspicuous veins tending to be longitudinal; 2n=16. Native of Eurasia, common as a weed in our range and elsewhere. May-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.