DESCRIPTIONS OF TRIBES AND GENERA. 



101 



See. II. A rth rather um (Beau v. as a genus). Awns 

 naked, deciduous. 



See. III. Stipagrostis (Nees as a genus. Schistachne, 

 Fig. & De Notar.). Awns plumose, deciduous. Grasses of 

 the high plains and deserts of Africa and Western Asia. 



102. (109) Stipa L. Panicles usually expanded, empty 

 glumes narrow, often awned, longer than the flowering 

 glumes, the latter usually with a 

 hairy callus ; awns geniculate, 

 usually twisted below the genicu- 

 lation, finally deciduous. 



Species about one hundred, 

 distributed throughout the tem- 

 perate and tropical zones, growing 

 especially on elevated plateaus 

 and savannas, and upon rocky 

 soil. Leaves frequently filiform 

 or stiff and rush-like. 



St. pennata L., with long plu- 

 mose awns, together with St. tirsa 

 Stev. and the following species 

 (viz., St. capillata), form the prin- 

 cipal grasses of the Russian 

 Steppes. St. pennata is also an 

 ornamental grass for dry bou- 

 quets. 



St. capillata L. (Fig. 44) has 

 naked awns that are curved irreg- 

 ularly back and forth towards the 

 end. The fruiting glume with its pointed callus easily 

 bores through the skin of sheep, reaches the intestines 

 and causes death (especially in Russia), as does the 

 " Porcupine grass" (St. spartea Trim) of North America. 

 Upon the prairies and especially upon the elevated plains 

 of the West the numerous species of Stipa form a con- 

 siderable portion of the "bunch" grasses, and furnish 

 much but rather coarse grazing for stock. St. tenacissima 

 L. (Macrochloa tenacissima Kunth) is called "Esparto" in 

 Spain and Haifa or Alfa in North Africa; it has con- 

 tracted panicles, two-cleft flowering glumes awned from 



Fig. U. — Stipa capillata L., ral. 

 Callus. 



