Stems cespitose from a short rhizome, 3-8 dm, glaucous, finely striate, without foliage lvs; basal sheaths to 10 cm, purple-brown at base, bristle-tipped; invol lf 1-2 dm, a fourth to a third as long as the stem; infl appearing lateral, 3-6 cm, freely branched and many-fld; fls prophyllate; tep lance-acuminate, 2.6-4 mm, slightly shorter to slightly longer than the dark purple- brown, shining, trilocular, beaked fr; anthers 6, about as long as the filaments; 2n=40, 42. Native of Eurasia and n. Afr., intr. in wet meadows and along roads in our range, as in N.Y., Ont., and Mich.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.