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



Culms usually 1 m or more tall. 



Spikelets mostly not more than 6-flowered, purplish. 



39. E. TRICHODES. 

 Spikelets mostly 8- to 15-flowered, stramineous to bronze. 



40. E. PILIFERA. 



Panicle at maturity about as broad as long. 

 Panicle purple, the branches slender but rigid. 



41. E. SPECTABILIS. 

 Panicle green to leaden, the branches capillary, fragile. 



Spikelets appressed and distant along the nearly simple panicle 



branches 44. E. refracta. 



Spikelets on long pedicels. 



Lemmas 2 mm long 42. E. elliottii. 



Lemmas 3 mm long 43. E. acuta. 



Figure 269.— Eragrostis obtusiftora. Plant, X Yi, two views of floret, X 10. (Tourney, Ark.) 



Section 1. Cataclastos Doell 



Rachilla of spikelets disarticulating between the florets at maturity. 

 1. Eragrostis obtusifiora Scribn. (Fig. 269.) Culms erect or 

 ascending, firm, wiry, 30 to 50 cm tall, from stout creeping rhizomes 

 with closely imbricate hard spiny-pointed scales; sheaths pubescent 

 or pilose at the throat; blades firm, glaucous, flat, becoming involute 

 at least toward the spiny-pointed tip, 5 to 10 cm long, 2 to 3 mm wide 



