Bui. 201 , U. S. Dcpt. of Agriculture. 



Plate III. 



Fig. 1.— Bouteloua Rothrockii under Protection just below the Northern 

 Foothills of the Santa Rita Mountains, Ariz. 



Fig. 2.— Bouteloua Aristidoides in a Favorable Season on Desert Mesas, South 



of Tucson, Ariz. 



