Erect perennial from a deep root, glabrous to villous, 3-10 dm, usually simple below, umbellately or paniculately branched above; lvs not ciliate, the cauline ones alternate, linear to elliptic, 3-6 cm, those subtending the primary branches similar, whorled, those of the infl smaller and often opposite; involucres numerous, forming a corymbiform or paniculiform cyme to 3 dm wide; pedicels, except a few lower ones, less than 1 cm; appendages white (green), conspicuous, ovate or oblong to obovate or rhombic, commonly longer than wide, 1.5-4 mm; seeds ovoid; 2n=28. Dry woods and old fields in the e., in the w. abundant on prairies; Mass. and N.H. to Minn., s. to Fla. and Tex. June-Sept. (Tithymalopsis c.) Two confluent geographic vars:
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.