The saguaro cactus, Carnegiea gigantea, is the state flower of Arizona. It is native to the Sonoran desert that ranges from the southern ends of both California and Arizona and the northern tip of Mexico.  It is a columnar cacti that can grow up to 50 feet during its life span that can exceed 200 years. 

Although it is not easy to survive in the hot, arid desert, the saguaro has adapted to its hostile environment in a variety of ways.  The saguaro cactus can store vast quantities of water within its expandable ribs during wet periods and it relies on those reserves during periods of drought.  Rather then leaves, the saguaros are covered with spines that not only minimize water loss and exposure to the sun's rays but also protect it from wildlife.

In addition to being a beautiful addition to the Sonoran landscape, the saguaro has been used by desert inhabitants throughout history.  The flesh, seeds, and juice of the saguaro fruit are used to make wine, jams, syrup, and candy.  The Tohono O'odham Indians celebrated their harvest of the saguaro fruit and sufficient rainfall  by forming a friendship circle around the great cactus. 

Do saguaros really expand to store water? 
How do other organisms interact with the saguaro? 
Do the yearly climatic fluctuations affect the growth cycle? 
Why do the saguaro flowers attract pollinators? 
 

Dohl, Kevin. Desert Harvest. http:www.tucsonweekly.com/tw/06-22-95/cover.htm