Found throughout the United States, primarily a weed of turfgrass. Stems prostrate, 4-angled, hairy, radiating out from the taproot. Leaflets have toothed margins, are widest at the apex, and have a projecting tip in the center of the leaf. The central leaflet is borne on a short stalk, while the lateral leaflets arise from the central petiole.
Stipules are present at the base of the petioles.
However, the longer stalk of the central leaflet compared to lateral leaflets, small projecting tip at the leaflet apex, and toothed margins are important characteristics that help to distinguish black medic from other trifoliate legumes.