The deserts of the American Southwest boast a remarkably 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 pineapple cactus, are less conspicuous but also more rare and in need of special protection and conservation.