Hypanthium elongate, pedicel-like; cal-lobes unequal, the lowest triangular, acute, larger than the 4 ovate-oblong obtuse upper, the 2 uppermost connate about half-length; standard broadly obovate to orbicular; wings shorter than the standard, oblong- obovate, clawed, biauriculate at the base of the blade; keel curved upward, about equaling the wings; stamens 10, monadelphous, the anthers alternately oblong and subglobose; joints of the fr 2, the lowest generally sterile and stipe-like, the upper fertile, flattened, tipped with the hooked persistent style; perennial herbs with pinnately trifoliolate lvs and small fls in short leafy spikes; stipules adnate to the petiole and connate into a tube around the stem, subulate-tipped. 25, mostly warm reg.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
