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



2.5 cm long. OL (A. reverchoni Vasey.) Dry or rocky hills and 

 plains, Texas to Utah, Nevada, and southern California, south to 



Puebla, Mexico (fig. 969). 

 23. Aristida purpurea 

 Nutt. PURPLE THREE- 

 AWN. (Fig. 970.) Per- 

 ennial, often in large 

 tufts; culms 30 to 50 

 cm tall; blades usually 

 involute and less than 

 10 cm long, 1 to 1.5 mm 

 wide when unrolled; 



FIGURE 966. Aristida spiciformis, X 1. 

 1115, Fla.) 



(Combs and Baker 



the body tapering to a scarcely beaked 

 summit, tuberculate-scabrous in lines 

 from below the middle to the summit; 

 awns nearly equal, spreading, 3 to 5 cm 

 long. 31 Dry hills and plains, Arkan- 

 sas and Kansas to Utah and southern 



FIGURE 967. Distribution of 

 Aristida spiciformis. 



panicle narrow, nod- 

 ding, rather lax and 

 loose, usually purplish, 

 10 to 20 cm long, the 

 branches and longer 

 pedicels capillary, more 

 or less curved or flexu- 

 ous; first glume 6 to 8 

 mm long, the second 

 about twice as long; 

 lemma about 1 cm long, 



FIGURE 969. Distribution of 

 Aristida glauca. 



California, south to northern Mexico 

 (fig. 971). ARISTIDA PURPUREA var. 

 LAXIFL6RA Merr. Panicle few-flowered, 

 the capillary branches bearing 1 or 2 

 spikelets. 01 Texas to Arizona. 



24. Aristida roemeriana Scheele. (Fig. 972.) Differing from 

 A, purpurea chiefly in the smaller spikelets; first glume 4 to 5 mm 



FIGURE 968 Aristida glauca, X 1. 

 (Reverchon 1237, Tex.) 



