saguaro

The giant columnar cactus of the Sonoran Desert — Carnegiea gigantea — the largest cactus in the United States, reaching 40 feet or more, living 150 to 200 years, and weighing several tons when fully hydrated. A saguaro does not grow its first arm until it is 50 to 75 years old. Its pleated trunk expands like an accordion to store water after rain. Gila woodpeckers and elf owls nest in holes carved into its flesh. The saguaro is the defining organism of its desert — remove it and the ecosystem loses its architecture.