Fls perfect or the lower ones staminate; cal very small; cor gamopetalous, funnelform, 5-lobed; stamens mostly 10, with long, slender filaments; fr prickly, oblong to linear, obtusely tetragonal, the sutures (collectively forming a replum) about as wide as the persistent valves and separating from them at maturity; sprawling perennial herbs, armed with numerous stout hooked prickles; lvs bipinnate, sensitive, with small lfls; fls rose-purple, numerous in axillary peduncled heads. Nearly 600, New World. Description here based entirely on the small series Quadrivalves of section Batocaulon, forming the traditional genus Schrankia
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.