The Arizona Sonora Desert stretches from central Arizona south into the state of Sonora, Mexico and west into portions of Southern California. It is the hottest and driest desert in North America with an area of over 120,000 square miles. Its most prominent landmark is the saguaro cactus, but the biodiversity of the desert is truly amazing. The Desert is generally divided into seven regions according to characteristic vegetation: Lower Colorado Valley, Arizona Upland, Plains of Sonora, Foothills of Sonora, Central Gulf Coast, and Magdalena Region. Other major types of cactus, some of which are shown in the panorama, include Cholla, beavertail, hedgehog, fishhook, prickly pear, night blooming cereus, and organ pipe. The picture above show the variety of plant species found in the Desert, such as Creosote bush and bursage, Indigo bush, Mormon tea, and mesquite. Prominent in the panorama is a spindly ocotillo cactus, which sprouts leaves only in the wet season.