200 



A TEXT-BOOK OF GRASSES 



awn. This awn is usually tightly twisted below, the 

 upper part being once or twice bent. In some species 

 (S. spartea Trin.) (Fig. 36) the awn is stout and several 

 inches long; in others it is beautifully plumose with silky 



hairs (S. pennata L. of 

 the Russian steppes and 

 S. spetiosa Trin. & Rupr. 

 of California). The vari- 

 ous species form an 

 important part of the 

 forage on the plains and 

 foothills of the south- 

 western states and 

 Mexico. The esparto- or 

 alfa-grass of Spain and 

 Algeria (S. tenacissima 

 L.) furnishes a fiber that 

 is used for paper and for 

 cordage. The sleepy- 

 grass (S. Vaseyi Scribn.) of Colorado and New 

 Mexico because of narcotic qualities is injurious to 

 horses. Two species of the Old World are said to 

 be poisonous (S. inebrians Hance and S. sibirica 

 Lam.). 



231. Muhlenbergia Schreb. A large genus of 

 mostly American grasses, especially abundant on the 

 dry uplands of the southwestern states and Mexico. 

 It grades on the one hand into Sporobolus, from 

 which it differs in having an awned or mucronate lemma, 

 and on the other into Epicampes, from which it differs 

 in having a relatively firmer lemma. Many species are 

 important constituents of the forage upon grazing areas 

 in the Southwest. One species of the allied genus 



