Plants perennial; rhizomatous, rhizomes slender, well-developed. Culms 25-60 cm tall, 1-2 mm thick, often decumbent, sometimes erect; internodes mostly scabrous, retrorsely hispidulous below the nodes. Sheaths longer than the internodes, scabridulous; ligules 0.5-2 mm, truncate to obtuse, erose or lacerate; blades 4-12 cm long, 1-2.6 mm wide, flat to involute distally, not arcuate, scabrous abaxially, hirsute or scabrous adaxially. Panicles 4-12 (17) cm long, 0.3-2.4 cm wide, contracted, interrupted below; branches 0.3-3 cm, usually appressed, occasionally diverging up to 30° from the rachises; pedicels 0.1-1.2 mm, scabrous to hirsute. Spikelets 2.4-3.5 mm. Glumes equal, 1.5-3.5 mm, 1-veined, veins scabrous, apices acute or acuminate, usually awned, awns, if present, to 1.5 mm; lemmas 2.4-3.4 mm, elliptic, pubescent on the lower the 1/2 of the midveins and margins, hairs to 0.6 mm, tawny, apices acuminate to acute, awned, awns 0.1-3 (5) mm; paleas 2.2-3.4 mm, elliptic, intercostal region pubescent on the lower 1/2, apices acuminate to acute; anthers 1.8-2.4 mm, orange. Caryopses 1.7-2 mm, fusiform, brownish. 2n = 60.
Calif., Ariz., N.Mex., Tex.
Muhlenbergia glauca grows on calcareous rocky slopes, cliffs, canyon walls, table rocks, and volcanic rock outcrops, at elevations of 1200-2780 m. Its range extends from the southwestern United States to central Mexico. M. glauca resembles M. polycaulis, but differs in its shorter lemma awns and strongly rhizomatous habit.
"decumbent" is not a number.