Black medick is a procumbent annual, biennial or short-lived perennial wildflower. It is native in grassy places and rough ground, this particular plant was growing the the cracks of a pavement.
Black medick has small (2–3 mm) yellow flowers grouped in tight bunches. On larger plants the flower heads may reach 8 mm or more. The fruit is a single-seeded pod, 1.5 to 3 mm in diameter, that does not open upon maturation, but hardens and turns black when ripe. Each pod contains a single amber-coloured seed.
Black medick is a good source of nectar for bees to use to make honey. It is frequently found in natural pastures, and may be planted in order to create artificial meadows, especially on dry land.
The presence of black medick in large concentrations as a lawn weed may indicate that the soil is poor in nitrogen. As black medick and other clovers fix nitrogen in the soil, this deficiency can improve over time due to the presence of these plants.