MANUAL OF THE GRASSES OF THE UNITED STATES 



377 



30 to 60 cm tall ; sheaths glabrous, mostly basal, becoming flat and loose ; 



blades flat to involute, 1 to 2 mm wide ; panicle narrow, rather loose, 5 to 



15 cm long, the branches 

 ascending or appressed, 

 floriferous from base ; 

 first glume acute, 1.5 

 mm long, the second 

 longer, broader, 3- 

 nerved, 3-toothed; 

 lemma about 4 mm long, 

 pilose below, scaberu- 

 lous above, the awn 

 slender, flexuous, 1 to 

 1.5 cm long, sometimes 

 shorter. 91 (M. trifi- 

 da Hack., M. gracilis of 

 authors, not Kunth.) — 

 Canyons, mesas, and 

 rocky hills, 2,000 to 

 3,000 meters, Montana 

 to Utah and central Cali- 

 fornia, south to western 



Figure 779.— Distribution of 

 Muhlenbergia schreberi. 



Texas and southern 

 Mexico (fig. 784). 



35. Muhlenbergia vi- 

 rescens (H.B.K.) Kunth. 



SCREWLEAF MUHLY. (Fig. 



785.) Perennial; culms 

 densely tufted, erect, 40 

 to 60 cm tall, the old 

 basal sheaths flattened 

 and more or less coiled; 

 ligule, except the margin, 

 delicate, 3 to 10 mm long ; 

 blades flat or those of the 

 innovations involute, 

 mostly elongate and flex- 

 uous ; panicle narrow but 

 rather loose, 5 to 10 cm 

 long, the branches erect; 

 spikelets, excluding 



Figure 778.— ,4, Muhlenbergia schreberi. Plant, X W, plumes and aWIlS, about 5 111111 long, 



floret, X 10. (Curtiss 3400, Tenn.) B, M. curtisetosa. Glumes flip crlnniPQ «1 i (rli 1 1 v 

 and floret, X 10. (Wolf 30, 111.) l / & UUllb!3 bllgllHV 



shorter, acute, the sec- 

 ond 3-nerved ; lemma and palea pubescent on the lower half, the lemma 

 tapering into a slender flexuous awn 1 to 1.5 cm long. % — Can- 



