36G MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Figure 745.— Distribution of 

 Muhlenbergia cuspidata. 



caryopsis does not fall from the lemma and palea 

 as in most species of Sporobolus, nor can the pericarp 

 be separated from the grain by moistening it. 



13. Muhlenbergia asperifolia (Nees and Mey.) Pa- 

 rodi. Scratchgrass. (Fig. 749.) Perennial, pale or 

 glaucous, with slender 

 scaly rhizomes; culms 

 branching at base, 

 spreading, slender, 

 compressed, 10 to 40 

 cm tall, the branches 

 ascending or erect; 

 sheaths somewhat 

 compress e d-keeled, 



usually overlapping; ligule minute, erose- toothed; 

 blades flat, crowded, scabrous, mostly 2 to 5 cm long, 



1 to 2 mm wide ; panicle 

 diffuse, 5 to 15 cm long, 

 about as wide, the 

 capillary scabrous 

 branches finally widely 

 spreading, the panicle 

 at maturity breaking 

 away; spikelets 1.5 to 



2 mm long, occasion- 

 ally 2-flowered, the 

 pedicels capillary; 

 glumes acute, from 

 half to nearly as long 

 as thespikelet; lemma 

 thin, broad, minutely 

 mucronate from an 

 obtuse apex. % (Spo- 

 robolus asperij olius 

 Nees and Mey.) — 

 Damp or marshy, 

 often alkaline soil, 

 along irrigation ditches 

 and banks of streams, 

 Illinois and Alberta to 

 British Columbia, 



south to Texas, California, and Mexico (fig. 750); 

 southern South America. The caryopsis is frequently 

 affected by a fungus (Tilletia asperifolia Ell. and 

 Everh.) which produces 

 a large globular body. 



14. Muhlenbergia 

 torreyana (Schult.) 

 Hitchc. (Fig. 751.) Per- 

 ennial, strongly com- 

 pressed at base, with 

 short very scaly rhi- 



JSEF iSfclSlf. zomes; culms simple, or 



plant, x i; glumes and sparingly branching at base, erect, 30 to 60 cm tall; 



io% X I0 (Cratty ' blades elongate, rather firm, flat or folded, 1 to 3 



Figure 746. — Muhlenbergia wrightii. 

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

 (Standley 8249, N.Mex.) 



Figure 747.— Distribution of 

 Muhlenbergia wrightii. 



