Bromus tectorum, cheatgrass

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Intermountain Flora
Small annuals with soft hispid pubescence throughout; culms 1-5 (7) dm tall; lingules 1-2.5 (4) mm long, lacerate-erose; auricles lacking; blades flat, relatively narrow, 2-3.5 (7.5) mm broad; panice (4) 6-12 (15) cm long, nodding, often densely branched, the lower one spreading or reflexed; spikelets small, (12) 15-20 (24) mm long, few flowered, 3-6, the nerves usually prominent; glumes narrow-lanceolate to lanceolate, the first glume 5.5-7 mm long, 1-nerved, the second 8-11 mm long, 3-nerved; lemmas 10-12.5 (17.5) mm long, rounded to slightly carinte on back, 1-1.5 mm broad, glabrous to villose, the narrow apical teeth 1-3 mm long; awns (7) 10-17 mm long, straight or very slightly geniculate; anthers 0.5-0.7 mm long, usually included in the lemma (cleistogamous); 2 n = 14.
Cronquist, A., Holmgren, A.H., Holmgren, N.H., Reveal, J.L., and Holmgren, P.K. (1977) "Intermountain Flora" pg. 200, vol. 6, The New York Botanical Garden New York.