Cal 4-lobed through fusion of the upper 2, the lowest lobe the longest, the two lateral ones the shortest, all exceeding the tube; standard round-obovate; keel-pet narrowly oblong, nearly straight, auriculate at base; stamens 10, the uppermost one coherent with the others only near the middle; style elongate, glabrous; fr flat, several-seeded, hirsute; tall, woody or half-woody twiners with ovate stipules, large, pinnately trifoliolate lvs, and reddish-purple fls in dense axillary racemes or panicles. 12, e. Asia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.