Perennial, 3-6 dm, sparingly branched; lfls 11-29, oblanceolate to oblong, 1-3 cm, peduncles from the upper axils, stout, 1-3 dm; racemes dense, 5-10 cm; bracts brownish, lanceolate; fls rosy, 10-14 mm; cal-lobes linear-setaceous, 3-5 mm, usually ciliate or long-hairy; fr obliquely rotund-ovate, 5-8 mm, strongly and coarsely reticulate-veined, the broadly rounded lower suture beset with short stout spines or coarse teeth; 2n=28. Native of s. Europe, occasionally intr. in our range. June, July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.