Cal irregular, 4-lobed through fusion of the 2 upper lobes; lowest lobe the longest, much exceeding the tube; standard orbicular or broadly round-ovate, its sides at base folded over the other pet; wings much shorter than the keel, oblong, upcurved; keel-pet broadest near the middle, abruptly contracted and strongly curved upward into a beak; stamens 10, diadelphous; style bearded along the upper side; fr subterete, elongate, coiled after dehiscence, with several woolly seeds; twining or trailing herbs with pinnately trifoliolate, stipellate lvs and long-peduncled heads of small pink-purple to white fls, each closely subtended by a pair of striate bracteoles. 3, e. N. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
