Bromus carinatus, mountain brome

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Intermountain Flora
Tall perrenials, often flowering the first season, without rhizomes; culms (3) 6-9 (14) dm tall, glabrous to pubescent; sheaths pilose, at least at the throat, rarely all glabrous; lingules relatively long, 1-3 (4) mm, erose, glabrous to pilose; auricles, if any at all, very small; blades flat and broad, (2) 3.5-9 (12) mm wide, rarely involute, scabrous to pilose or glabrous; panicles usually relatively long, (5) 10-20 (30) cm, loosely contracted and nodding; spikelets relatively long, 20-30 (40) mm, 4- to 7- (10)-flowered, strongly compressed; glumes lanceolate, strongly keeled, the first glume 7-11 mm long, 3- to 5-nerved, the second 9-13 mm long, 5- to 7-nerved; lemmas 11-15 (17) mm long, carinate-keeled, glabrous to scabrous or hirsute, the apex slightly bifid to entire; awns (3) 4-6 (8) mm long; anthers 1.5-3.5 mm long, sometimes small and included (cleistogamous) within the lemma; 2 n = 28, 42, 56, 70.

Cronquist, A., Holmgren, A.H., Holmgren, N.H., Reveal, J.L., and Holmgren, P.K. (1977) "Intermountain Flora" pg. 188, vol. 6, The New York Botanical Garden New York.