234 A TEXT-BOOK OF GRASSES 



with their antrorsely scabrous avms are sharp-pointed so they 

 readily penetrate clothing and the wool of sheep, because of which 

 these species are considered a great pest. The following key will 

 distinguish the common species: 



A. Panicle contracted, dense. 

 B. Awn % inch long. 



c. Culm pubescent below panicle B. rvbens L. 



oc. Culm glabrous below panicle B .madritensisL. 



BB. Awn about 3<^ inch long B. hordeaceus L. 



AA. Panicle open, the branches spreading. 



B. Awn twisted and bent B. trinli Desv. 



BB. Awn not twisted and bent. 



c. Sheaths smooth B. seccdinus L. 



cc. Sheaths pubescent. 



D. Awn 13^ to 2 inches long B. villosus 



DD. Awn not over % inch long. [Forsk. 



E. First glume 1-nerved B. tectorum L. 



EE. First glume 3-nerved. 



F. Lemmas pubescent B. arenarius 



[LabiU. 



FF. Lemmas glabrous. B. pratensis 



[Ehrh. 



