A prostrate, spreading annual. Flowers terminal, in dense rounded clusters, very small, yellow, in the typical configuration of members of the pea family. Blooms March–November. Leaves alternate, compound with 3 leaflets to ¾ inch long, the leaflets shallowly toothed. Stems usually angled or square, with soft hairs. Fruits a tiny, coiled, 1-seeded pod, almost black.
There are 5 species of Medicago in Missouri, including Medicago sativa (alfalfa) and 3 species of bur clover.