Sep 5, the 3 outer small, the 2 inner (lateral) ones, called wings, much larger and often petaloid; pet 3, all ±united below with the filament-tube, the 2 upper ones similar, the lower one keel-shaped or boat-shaped with a fringe-like crest (in our spp.); stamens (6)8, the filaments monadelphous into a sheath split along the upper side; ovary bilocular; seed usually with an aril; ours herbs with alternate or verticillate lvs and small (except in the first sp.) fls in open to dense and spike-like or head-like racemes. 500, cosmop.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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