Glabrous, 2-4 dm, often branched from the base, the decumbent stems often emitting new shoots the next year; young stems and lvs commonly somewhat red-tinted; cauline lvs numerous; oblanceolate to obovate, or the upper oval to ovate, commonly sessile; lvs subtending the umbel broadly elliptic to ovate or subcordate, those of the umbel broadly triangular-reniform, tending to be connate; rays of the primary umbel usually 3; fr smooth, 3 mm; seeds pale gray, 1.5-2 mm, deeply and uniformly pitted on both faces; 2n=28. Moist woods and shaded hillsides; Pa. to s. Ont., Mich., and Minn., s. to Fla. and Tex. Apr.-June. (Tithymalus c.; Galarhoeus c.) Southern plants, extending n. to Va., Ky., and Mo., with all cauline lvs oblanceolate and long (5-12 mm)-petioled, have been segregated as var. erecta Norton.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent on rocky or gravelly wooded slopes, mostly along streams and about lakes, sometimes in the talus of cliffs and rarely in the open, if so, usually about gravel pits.