MANUAL OF THE GRASSES OF THE UNITED STATES 



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smooth, spreading; away from the branches, the prophyllum con- 

 spicuous; blades mostly about 1 mm wide, flat, 2 to 5 cm long, early 

 deciduous from the sheaths; panicle 5 to 10 cm long, open, the slender 

 branches and branchlets brittle, widely spreading, bearing rather few 

 long-pedicled spikelets; glumes narrow, acuminate, slightly unequal, 

 the second about 2 mm long; lemma purple, acuminate, sparsely 

 pubescent, 3 to 4 mm long, with a delicate awn about 5 to 8 mm 

 long. % — Dry mesas and hills, canyons, and rocky deserts, 

 western Texas to Colorado, Nevada, and southern California, south 



Figure 7*6— Muhlenbergia polycaulis. Plant, X 1: glumes and floret, X 10. (Type) 



to northern Mexico (fig. 793). Known also as mesquite grass and 

 black grama. 



42. Muhlenbergia torreyi (Kunth) Hitchc. Rixggrass. (Fig. 

 794.) Perennial in loose tufts, with numerous innovations, the base 

 decumbent or forming short rhizomes, the plants usually gregarious, 

 sometimes forming large patches or " fairy rings"; culms slender, 10 

 to 30 cm tall; leaves in a short basal cluster; blades closely involute, 

 usually 2 to 3 cm long, falcate or flexuous, forming a crisp curly 

 cushion; panicle open, usually about half the entire length of the 



