Annual or short-lived perennial 2-12 dm with tufted or solitary culms, the herbage glabrous to scabrous or pubescent; lvs flat, mostly 2-8 mm wide, mostly under 10 cm; ligules 1.5-3.5 mm, finely erose-ciliate; infl 0.5-2 dm, erect or nodding; glumes dissimilar, the first 1-3 mm, narrow, 0.1-0.3(-0.4) mm wide in side-view, with scabrous keel, the second 1.2-4.2 mm, broader, 0.5-1 mm wide in side-view; lemmas awnless, blunt to acute, smooth to scaberulous, the first 1.4-4.4 mm, the second a bit shorter; anthers small, mostly 0.3-0.7 mm; 2n=14. Moist meadows, streambanks, and shores of ponds or lakes; Nf. to Alas., s. to Fla., W.I., and Mex. Two vars. with similar ranges:
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.