Annual, to 1 m, sparingly and somewhat umbellately branched above; lvs narrowly triangular to oblong, lanceolate, or ovate-oblong, 4-10 cm, the principal ones with the blade rounded at base and less than twice as long as the petiole; fls in dense terminal infls 1-3 cm; staminate fls with 5 sep, 5 pet, and 10-14 stamens; pistillate fls apetalous, the 6-10 sep accrescent to 1 cm; styles 3, each 2-3 times dichotomous, the stigmas thus 12-24; 2n=20. Dry, usually sandy soil and waste places; O. to Ind. and Neb., s. to Fla. and Tex. Ours are var. capitatus.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.