370 



GRASSES OF IOWA. 



Fig. 171. Blue Grama, {Bouteloua oligai^tachya). One of the most valuable of 

 the western grasses. Occurs in northern Iowa from Lyon to Dickinson 

 county. (F. Lamson-Serlbner. U. S. Dept. Agrl.) 



AGROPYRON OR WHEAT GRASSES. 



This genus contains quite a number of valuable grasses as 

 well as some members that are quite difficult to exterminate, as 

 the common quack grass (Agropyron repens), and as the Agro- 

 2yyron occidentale has become in eastern Minnesota. Some of the 

 members of this genus are certainly among the most valuable 

 of the grasses of the plains and Rocky Mountain country. 

 Thus the A. occidentale is one of the most valuable grasses of 

 the plains, while Agropyron tenerum and A. pseudo-repens and A. 

 richardsoni and A. divergens are valuable in the foothills and 

 mountains. 



Western Wheat Grass {Agropyron occidentale). — During 

 the summer one may see along our great trunk lines a con- 



