Spikelets strongly compressed, mostly 2-fld, disarticulating below the glumes and between the lemmas; rachilla prolonged behind the upper palea, seldom bearing a third floret; glumes keeled, dissimilar, the first 1(3)-veined, linear or rather narrowly oblong, usually distinctly shorter than the firmer, much wider, 3(5)-veined, scarious-margined second one, which nearly equals the first lemma; lemmas firm, slender, rounded on the back or keeled distally, obscurely veined, awnless or (especially the upper one) with a straight or bent, subterminal awn; palea hyaline, nearly equaling the lemma; seeds with minute embryo and liquid endosperm; ligule membranous; annual or more often perennial, with tufted or solitary stems, not rhizomatous, and with shining, often slender and spike-like panicles. 4, N. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.