Bush forms of Mucuna pruriens grow rapidly, but have a more compact growth habit than vining types. The leaves are large and trifoliate with lateral leaflets 7–15 cm long, 5–12 cm wide. Flowers are light purple or white, resulting in pods 4-13 cm in length. Wild forms of M. pruriens have pods with hairs that, due to a protein called mucunain, are irritating to the skin and can cause severe itching; cultivated varieties (var. utilis) have non-stinging hairs. Mature, dry pods have a hard shell with each pod containing 4-6 seeds which, depending on the variety, vary in color (from black to white, brown, or mottled) and are 1-2 cm long.