saguaro, cholla, ocotillo and barrel cacti in the semi-desert landscape of usery mountain regional park

activities arizona backgroundn barrel blue cacti cactus catuses cholla clouds county desert environment flora forest formations geological geology hiking landscape layers maricopa mountain national nature near ocotillo outdoors park pass phoenix plants precambrian prickly reginal regional reserve rock rocks saguaro sates scarface semidesert shadow shrubs spectacular tonto trail trails united usery valley vascular views vista wilderness with