Click on image for larger version of photo.
From the Wikipedia:
The Saguaro, pronounced "sah-wah-roh", (Carnegiea gigantea) is a large, tree-sized cactus species in the monotypic genus Carnegiea. It is native to the Sonoran Desert in Arizona and California, United States and northern Mexico.
The common name of the cactus, saguaro, is a Spanish-language adaptation of a word used by a local aboriginal American nation, the Tohono O'odham, for the plant. Local English speakers pronounce it /səˈwɑɹo/.
Saguaros are slow growing, taking up to 75 years to develop a side arm. The arms themselves are grown to increase the plants reproductive capacity (more apices equal more flowers and fruit). The growth rate of saguaros is strongly dependent on local precipitation patterns ...