cottontop cactus (echinocactus polycephalus), cacti in the stone desert among the rocks, mojave desert joshua tree

echinocactus polycephalus cottontop cactus manyheaded barrel california arid arizona desert cactaceae cacti cannonball dry ecology hardy landscape mojave national nature pear pink prickly red sharp spine spines succulent thorn valley vegetation wild wildlife north america sonoran saguaro park ajo mountain drive succulents barrell rock wilderness yucca