Infl 1-2 dm; pet 6-8 mm; stamens 10-25; anthers subglobose, 0.5 mm; style divided a fourth to a third of its length into linear stigmas; fr 4-5 mm; seeds minutely roughened and strongly wrinkled. Thin soil overlying sandstone, and on sand prairies; nw. Ind. to Minn., Neb., and Kans., and reputedly in ne. Tex. July, Aug. Fls open in late afternoon only.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.