Cactus Flower Power

All Photos by Marty Horowitz 3/30/2016
As members of the same family (Cactaceae), cactus plants have flowers that look similar to each other. Fruits are similar as well : -) And for foliage, they've got spines.

Hedgehog Cactus flowers (Echinocereus fasciculatus) 

Saguaro flowers (Carnegiea gigantea)

State flower of Arizona

Engelmann Prickly Pear flowers (Opuntia engelmannii var. engelmannii)