MANUAL OP THE GRASSES OF THE UNITED STATES 383 



cm tall; sheaths with erect firm auricles, 4 to 10 mm long, rarely 

 longer; blades involute, scabrous; panicle narrow, sometimes almost 

 spikelike, grayish, 10 to 30 cm long, rarely longer; spikelets about 

 4 mm long; glumes about half as long as the spikelet, minutely sca- 

 berulous, obtuse; lemma minutely scaberulous, with an awn as much 

 as 4 mm long, rarely acuminate only. 01 (M. acuminata Vasey; 



FIGURE 789. Muhlenbergia parviglumis. 

 Panicle, X 1; glumes and floret, X 10. 

 (Vasey, Tex.) 



FIGURE 791. Distribution of 

 Muhlenbergia pauciflora. 



FIGURE 790. Muhlenbergia pauciflora. Plant, X 1; glumes 

 and floret, X 10. (Wright 732, Tex.) 



Sporobolus ligulatus Vasey and Dewey.) Canyons and rocky hills, 

 western Texas to Arizona and northern Mexico. 



46. Muhlenbergia rigida (H.B.K.) Kunth. PURPLE MUHLY. 

 (Fig. 800.) Perennial, densely tufted; culms erect, 60 to 100 cm 

 tall; leaves crowded at base, old sheaths persistent, the sheaths with 

 auricles 2 to 5 mm, rarely longer; blades flat or soon involute, flexuous, 

 those of the innovations involute; panicle dark purple, narrow, finally 

 loose and open, 15 to 30 cm long, the capillary branches ascending, 



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