CLEMENTS 



Desert Plains 



PLATE 28 



■HP*' _»ip^^.JW^* 



A. Boutdoua-HiUiria association, Empire Valley, Arizona. 



B. Bouteloua rothrockii and Aristida divaricata, Santa Rita Reserve, Tucson, Arizona. 



C. Bouteloua race?nosa consociation, Oracle, Arizona. 



