Bromus briziformis, rattlesnake chess

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Intermountain Flora
Small annuals; culms 1.5-5.5 (8.5) dm tall; sheaths usually densely retrorsely hispid; lingules 0.5-2 mm long, usually 1 mm, erose, pubscent; auricles lacking; blades flat, (1) 2-4.5 (6) mm broad, sometimes involute, pilose; panicles usually relatively short, 3-10 (20) cm long, nodding, and somewhat secund, usually very few spikelets; spikelets (15) 20-26 (30) mm long, strongly compressed, oblong-ovate, 8-12 mm broad, many-flowered, (7) 9-15, the florets widely spreading, glabrous, rarely scabrous; glumes oblong-lanceolate, the nerves faint, relatively short, the first glume 4.5-6 mm long, 3- to 5-nerved, the second 6.5-7.5 mm long, (5-) 7- to 9-nerved; lemmas relatively short, (7) 8-9.5 mm long and exceptionally broad, 2.8-4 mm in side view, rhombic-ovate, strongly inflated, the nerves several, very faint, the apex scarcely bifid; awns, when present, up to only 1 mm long; palea slender; anthers usually enclosed (cleistogamous), about 0.8 mm long; 2 n = 14.

Cronquist, A., Holmgren, A.H., Holmgren, N.H., Reveal, J.L., and Holmgren, P.K. (1988) "Intermountain Flora" pg. 195, vol. 6, The New York Botanical Garden New York.