Cacti of the Desert Southwest

The deserts of the American Southwest boast a remarkable diversity of drought-tolerant plant life, including many species found nowhere else on earth. And no group says "desert" quite like cacti. Their prickly nature notwithstanding, cacti and the desert habitats in which they reside are especially fragile. Indeed, Saguaro National Park and Organ Pipe Cactus National Monument were established primarily to protect the largest concentrations of these respective species. Others, such as the Pima pi…