MANUAL OF THE GRASSES OF THE UNITED STATES 



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Figure 570. — Muhlenbergia porteri. 

 Plant, X 1 ; glumes and floret, X 

 10. (Chase 5887, Tex.) 



54. Muhlenbergia arenicola Buckl. 

 (Fig. 573.) Resembling M. torreyi; 

 culms mostly 30 to 50 cm. tall; 

 blades usually straight and on the 

 average longer; panicle larger, mostly 

 pale, the branchlets and pedicels ap- 

 pressed; spikelets slightly longer, the 

 lemma scabrous, the awn 1 to 2 mm. 

 long. % — Sandy plains and mesas, 

 western Kansas to Arizona, south to 

 northern Mexico. 



55. Muhlenbergia setifdlia Vasey. 

 (Fig. 574.) Perennial, tufted; culms 

 erect, hard, wiry, 50 to 80 cm. tall; 

 sheaths with erect auricles, 2 to 10 

 mm. long; blades involute, fine, 

 scarcely 0.5 mm. thick, very sca- 

 brous, flexuous, as much as 20 cm. 



long; panicle narrow, open, 10 to 30 

 cm. long, the capillary branches as- 

 cending, flexuous ; spikelets, excluding 

 awns, about 5 mm. long, the glumes 

 one-third to half as long, obtuse to 

 subacute; lemma hairy on the callus, 

 otherwise smooth, tapering into a 

 flexuous awn 1.5 to 2 cm. long. Q| 

 — Rocky hills, western Texas and 

 northern Mexico. 



56. Muhlenbergia xerophila CO. 

 Goodding. (Fig. 575.) Culms 45 to 90 

 cm. tall, densely tufted, glabrous or 

 scaberulous; sheaths scaberulous; lig- 

 ule 2 to 4 mm. long, obtuse; blades 

 involute, 15 to 50 cm. long, 1 to 1.5 

 mm.- wide; panicle open (contracted at 

 maturity), 15 to 35 cm. long, with cap- 



