Cool season, annual bunchgrass. Stems 50–150 cm. Leaves: blades flat and ascending, 6–12 mm wide; sheaths with overlapping margins; ligule membranous. Inflorescence a two-sided terminal spike with short internodes, 6–12 cm long, rachis readily disarticulating at maturity. Spikelets 1 per node, 14–18 mm long, mostly with 2 florets, glumes narrow and linear. Lemmas with distinctively scabrous veins, distinctly keeled, the margins conspicuously pectinate-ciliate, awn 20–40 mm long; palea enclosed in floret. Disarticulation below the glumes; unit of dispersal the spikelet and subtending internode of the inflorescence rachis (Lavin in
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).