Stems erect, 2-7 dm, widely branched above; rays 4-7, rarely fewer, 1-3 cm, ±widely spreading, subequal; pedicels 2-6, usually unequal, to 1.5 cm, or the central fl of each umbellet sessile; fr 1.5-2 mm, varying from strongly tuberculate to nearly smooth; 2n=16. Dry sandy soil, chiefly on the coastal plain; Va. to Fla. and Tex., n. in the interior to Kans. Apr., May.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.