Fls resupinate, the banner lowermost; cal nearly regular, the tube hemispheric, the lobes subequal; standard rotund, much exceeding the other pet, with a minute median spur at the base; wings oblong, obtuse; keel-pet broadly semi-obovate, strongly incurved; stamens 10, diadelphous, the anthers all alike; style glabrous, strongly incurved to the pilose stigma; fr elongate, many-seeded, with a longitudinal ridge near each margin, tightly coiled after dehiscence; twining herbs with pinnately compound lvs of 3 stipellate lfls, and with solitary or clustered axillary fls. 45, New World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.