Thistle on Saguaro Famous for their accordion-like trunk which expands with rain to store water for the desert drought, the Arizona saguaro is an amazing survivalist. Their armor of long and short spines provides protection from animals but also shelter to some insects and birds, like the cactus wren the Arizona state bird. The thorny bull thistle is a likely companion. This art work watercolor painting southwest reminds me of my 18 years living in Phoenix.