Muhlenbergia mexicana (L.) Trin.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Vigorously rhizomatous; culms 3–9 dm; internodes dull and puberulent, especially toward the top; sheaths glabrous; blades 5–15 cm × 2–6 mm, glabrous; ligule membranous, 0.5–1 mm; infls terminal on the main stem or also on long leafy branches, the peduncles exserted 2–12 cm; panicles very slender to dense and lobulate, the terminal one 7–21 cm × 2–10 mm; spikelets closely clustered, mostly subsessile, 1.7–4.4 mm, the glumes narrow, shorter than or equaling the lemma, often cuspidate or with an awn-tip to 1.5 mm; lemmas 1.5–3.4 mm, awnless or with an awn-tip to 9 mm, the callus bearded; anthers 0.3–0.5 mm; 2n=40. In a wide range of moist or wet, open or wooded habitats; Que. and N.S. to B.C., s. to N.C., Mo., Tex., and Calif. (M. foliosa; M. ambigua, the awned form)