380 



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



pilose; panicles numerous, narrow, 2 

 to 12 cm. long; spikelets 3.5 to 4.5 

 mm. long; glumes abruptly acute or 

 acuminate, commonly aristate, 1.5 to 

 2 mm. or sometimes 3 mm. long, the 

 awn about half the entire length; 

 lemma 3- to 5-nerved, scabrous to 

 prominent]}'' ciliate on the lateral 

 nerves, the callus appressed-pubes- 

 cent; awn 10 to 30 mm. long. O 

 — Moist rocky hillsides, southern 

 Arizona; Mexico. 



Figure 529. — Muhlenbergia pectinate. Plant, X 1; 

 glumes and floret, X 10. (Type.) 



11. Muhlenbergia depauperata 



Scribn. (Fig. 530.) Culms 2 to 15 cm. 

 tall, densely tufted, erect, scabrous to 

 hispidulous below the nodes; blades 1 

 to 1.5 cm. long (rarely 3 cm.), 1 to 

 1.5 mm. wide, scabrous, puberulent 

 on the upper surface, with white car- 

 tilaginous midnerve and margins; 

 panicles narrow, spikelike, often in- 

 cluded, 1 to 4 cm. long (rarely to 6 

 cm.), the branches and pedicels 

 closely appressed; glumes narrow, 

 scabrous, about equal to or slightly 



longer than the floret, the tips often 

 spreading; first glume 2-nerved, bi- 

 dentate or entire, 2.5 to 3.5 mm. long; 

 second glume 1-nerved, acuminate- 

 aristate, 3 to 4 mm. long; lemma 3 to 

 3.5 mm. long, prominently 3-nerved, 

 scabrous above, sparsely pubescent 

 on the internerves, the straight awn 

 2 to 10 mm. long, rarely less. O 

 — Open gravelly places, Arizona and 

 New Mexico; northern Mexico. 



12. Muhlenbergia brevis C. 0. 

 Goodding. (Fig. 531.) Culms 3 to 20 

 cm. tall, erect, tufted, much branched 

 below; ligule 1 to 3 mm. long, lacer- 

 ate; blades flat to involute, 0.5 to 4 

 cm. long, scabrous or puberulent 

 above, scabrous below; panicles 1 to 

 2 cm. long, narrow, rather densely 

 flowered, the branches erect; glumes 

 scabrous, variable, shorter than the 

 floret; first glume 1 to 3 mm. long, 

 2-nerved, minutely to deeply bifid; 

 second glume 1.5 to 4 mm. long (usu- 



Figure 530. — Muhlenbergia depauperata. Plant, X 1; 

 glumes and floret, X 10. (Hitchcock 13560, N. Mex.) 



