Annual, climbing herb, growing up to 1 or 2 m high with angular, glabrescent, winged stems; leaves paripinnate; leaflets in a pair, ovate-oblong or elliptic, glabrous above, hairy along the veins beneath; terminal tendril twines around supporting plants or structures; stipules falcate, auricled at base, foliaceous; flowers purple, in axillary clusters, usually 1-3 on short pedicels; calyx about 1 cm, cleft halfway down; corolla white, pink or purple; stamens-10, diadelphous, sheath truncate; ovary subsessile or stipitate, style flattened and hairy below stigma; pods not winged, slightly curved, pubescent, 6-8 seeded, hairy.