Annual; stems tending to be erect, usually branched, to 8 dm, mostly pubescent; lf-segments elliptic to narrowly oblong, hirsutulous beneath; rays
1-4, mostly 3, in fr stiffly erect or ascending; pedicels 3-10, becoming much thickened and often clavate; fr lanceolate, 5.5-8 mm, concavely narrowed to a short beak, the ribs stout, from a little narrower than to more often equaling or wider than the intervals; 2n=22. Moist to dry sandy soil; se. Va., Ky., s. Ind., and e. Neb., s. to Fla., Tex. and Ariz. Mar.-May. (C. floridanum)
Two European biennials have been reported as casuals along the Atlantic seaboard. C. temulum L. has
6-10 rays, lance-ovate bractlets, and oblong to ovate lf-segments. C. bulbosum L. has 10-20 rays, lance- linear bractlets, and lanceolate to linear lf-segments.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.