402 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Figure 569. — Muhlenbergia pungens. Plant, X 1 ; glumes and floret, X 10. (Jones 6046, Utah.) 



Nevada, and southern California, 

 south to northern Mexico. Known 

 also as mesquite "grass and black 

 grama. 



52. Muhlenbergia arizonica Scribn. 

 (Fig. 571.) Perennial, in close tufts; 

 culms slender, erect or decumbent at 

 base, 15 to 40 cm. tall; sheaths 

 keeled; ligule thin, 1 to 2 mm. long, 

 decurrent; blades flat or folded, 

 mostly less than 5 cm. long, 1 to 

 2 mm. wide, the margins and mid- 

 nerve white, cartilaginous; panicle 

 open, 5 to 12 cm. long, 4 to 8 cm. 

 wide, the branches capillary, com- 

 pound; spikelets long-pedicellate, 

 about 3 mm. long, the glumes about 

 one-third as long, ovate, subacute; 

 lemma narrowly lanceolate, minutely 

 pubescent along the midnerve and 

 margins below, the awn about 1 mm. 

 long, from a minutely notched apex. 

 91 — Stony hills, southern Arizona 

 and northwestern Mexico. 



53. Muhlenbergia torreyi (Kunth) 

 Hitchc. ex Bush. Ringgrass. (Fig. 

 572.) Perennial in loose tufts, with 

 numerous innovations, the base de- 

 cumbent or forming short rhizomes, 

 the plants usually gregarious, some- 

 times 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, form- 

 ing a crisp curly cushion; panicle 

 open, usually about half the entire 

 length of the culm, commonly purple, 

 the capillary branches finally spread- 

 ing, the pedicels mostly as long as 

 the spikelets or longer; spikelets about 

 3 mm. long, the glumes, including 

 the awn-tip, about two-thirds as 

 long; lemma nearly glabrous, tapering 

 into a delicate awn about 3 mm. long. 

 01 (M. gracillima Torr.) — Plains, 

 mesas, and dry hills, western Kansas 

 and Wyoming to Texas and Arizona. 



