Climbing or sprawling annual herb to 80 cm. Leaves paripinnate with 3-8 pairs of leaflets, the rhachis usually terminating in a branched tendril; leaflets linear to oblong or obcordate, mucronate. Inflorescence subsessile with 1-2(-4) flowers per inflorescence. Corolla 10-30 mm, light reddish-purple, bluish or mauve. Pod 25-50 mm, brownish-black.