Purple Cactus, Yellow Flower

This might be my best shot so far of the unique colors of the Santa Rita prickly pear cactus in my backyard.

This genus of cactus (Opuntia violaceae) has a purplish, sometimes lavender, hue. The more stressed (dry) it is, the darker the color.  It grows in clumps, 4' x 5'  in size.  In comparison, mine is still an infant, measuring  2'x 2'.

It is just starting to turn purple.  It has been green since I stuck the single pad in the ground to start growing it almost seven years ago.

What is especially interesting about the Santa Rita cactus is that it is native to the valley in which I live, in the shadow of the Santa Rita mountains.  
It is now found growing in other areas of Arizona, New Mexico and California (and in pots around the world), but it's origin, and thus the derivation it's common name, is from the thirty or so mile stretch of the mountain range I so adore.