Cal-tube campanulate, the 5 lobes subequal; standard obovate or oblong, longer than the oblong erect wings, these with a prominent spur on the surface and a large retrorse basilateral lobe; keel blunt, shorter than and adherent to the wings; stamens 10, diadelphous, all free from the cor; style short; pod straight to more often ±coiled, usually indehiscent, 1-several-seeded; herbs with 3-foliolate, serrulate lvs, the terminal lfl stalked; fls discharging pollen by an explosive trip-mechanism, small, yellow or blue, in axillary heads or short head-like racemes. 80, Old World, mainly Eurasia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.