Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Cal-tube short, obconic, nearly regular, the lobes about equal, lanceolate, much exceeding the tube, the 2 upper connate part-way; pet about equal in length; standard broadly obovate, narrowed to the base; wings oblong, blunt; keel-pet oblong, somewhat incurved; stamens 10, diadelphous; ovary and fr pubescent; style glabrous; fr flat, dehiscent, 1–2-seeded; trailing, twining, or erect perennial herbs with 1-foliolate or pinnately 3-foliolate lvs and lacking stipellules; fls small, yellow, in axillary racemes, without bracteoles. (Dolicholus) 200, warm reg.