MANUAL OF THE GRASSES OF THE UNITED STATES 



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Figure 573. — Muhlenbergia arenicola. ^ 

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

 (Hitchcock 13602, Tex.) 



ligule truncate, 1 to 2 mm. long; 

 blades 15 to 50 cm. long, 1 to 2 mm. 

 wide, involute, glabrous, or sca- 

 berulous below; panicle 15 to 35 cm. 

 long, 2 to 4 cm. wide, densely flow- 

 ered, the branches appressed; spike- 

 lets about 4 mm. long; glumes sub- 

 equal, 2 to 3 mm. long, acute, more 

 or less erose, scaberulous; lemma 3.5 

 to 4 mm. long, the callus appressed- 

 pilose with hairs 1 to 1.5 mm. long; 

 awn straight, scabrous, 3 to 10 mm. 

 long. % — Canyons and rocky 

 slopes, Santa Cruz and Pima Coun- 

 ties, southern Arizona. 



60. Muhlenbergia expansa (DC.) 

 Trin. (Fig. 579.) Resembling M. 

 capillaris, in denser tufts, the old 

 basal sheaths forming a curly fibrous 

 mass; blades narrow, flat, becoming 

 involute; panicle relatively smaller, 

 narrower, the capillary branches and 

 branchlets mostly straight; spikelets 

 3.5 to 5 mm. long, the glumes one- 

 third to two-thirds as long, acute to 



acuminate ; lemma scaberulous, nearly 

 glabrous at base, awnless or with an 

 awn 2 to 3 mm. long, rarely longer. 

 % (M. trichopodes Chapm.) — Moist 

 pine barrens near the coast, Virginia 

 to Florida and Texas. 



61. Muhlenbergia reverchoni Va- 

 sey and Scribn. (Fig. 580.) Resem- 

 bling M . expansa, culms more slender, 

 foliage finer; glumes less than half as 

 long as the lemma, subacute or erose; 

 lemma with an awn 2 to 5 mm. long. 

 % — Rocky prairies, Texas and 

 Oklahoma. 



62. Muhlenbergia capillaris (Lam.) 

 Trin. (Fig. 581.) Perennial, in tufts; 

 culms rather slender, erect, 60 to 100 

 cm. tall; sheaths scaberulous, at least 

 toward the summit, and with auricles 

 mostly 3 to 5 mm. long; blades elon- 

 gate, flat or involute, 1 to 4 mm. wide, 

 those of the innovations narrower, in- 

 volute; panicle purple, oblong, diffuse, 

 one- third to half the entire height of 

 the culm, the branches capillary, flex- 



