MANUAL OF THE GRASSES OF THE UNITED STATES 361 



to 2 mm wide, scabrous; panicles narrow, 5 to 15 cm long, the branches 



rather distant, ascending; spikelets 



on short thick pedicels ; glumes broad, 



obtuse, subequal, less than 1 mm 



long; lemma narrow, 3 to 4 mm long, 



scabrous, the slender awn 1 to 3 



cm long, o — Open dry ground, 



Arizona and southern California to 



Peru. Cleistogamous spikelets are 



developed at the base of lower sheaths, 



solitary or few in a fascicle in each 



axil, each spikelet included in an in- 

 durate thickened, tightly rolled nar- 

 rowly conical reduced sheath, which 



readily disarticulates from the plant 



at maturity. The glumes are wanting 



and awn of lemma reduced, but the 



grain is larger than that of the spike- 

 lets in the terminal inflorescence, being 



about the same length (2 mm) but 



much thicker. 



3. Muhlenbergia depauperata 



Scribn. (Fig. 734.) Annual; culms 



in dense tufts, 5 to 10 or rarely 15 



cm tall, erect; blades scabrous, pubes- 

 cent on the upper surface, mostly less 



than 3 cm long, about 1 mm wide; 



panicle narrow, loosely spikelike, 



usually more than half the entire 



length of the plant, the branches ap- 



pressed; glumes narrow, scabrous, the first irregularly bidentate or 



entire, mostly 1 to 2 mm long, 

 occasionally reduced, the second, 

 a little longer; lemma narrow, 

 terete, prominently 3-nerved, 

 slightly pubescent along the inter- 

 nerves, about 4 mm long, the 

 delicate awn straight, about 1 cm 

 long. O —Open gravelly places, 

 Colorado, New Mexico, and Ari- 

 zona; Mexico. 



4. Muhlenbergia filiformis 

 (Thurb.) Rydb. Pull-up muhly. 

 (Fig. 735.) Annual, tufted, rather 

 soft and lax, erect or somewhat 

 spreading; culms filiform, usually 

 5 to 15 cm tall, sometimes as much 

 as 30 cm;ligule about 2 mm long, 

 blades flat, usually less than 3 cm 

 long; panicle narrow, interrupted, 

 few-flowered, usually less than 5 cm 



.Figure 733.— Muhlenbergia mic-osperma. Plant, X l° n g; glumes OVate, 1 mm long; 



.i; glumes and floret, x io. (Mearns 2780, Ariz.) lemma lanceolate, acute, mucron- 

 ate, 2 mm long, minutely pubescent, scaberulous at tip. O — Open 



Figure 732.— Muhlenbergia texana. Plant, X 

 1; glumes and floret, X 10. (Pringle 399, 

 Mex.) 



