cacti in the stone desert in the foothills, echinocactus polycephalus (cottontop cactus, many-headed barrel cactus

arizona desert polycephalus echinocactus cottontop cactus manyheaded barrel cannonball cacti california death ecology mojave national nature plant red sharp spines summer thorn travel usa valley arid background cactaceae dry flora flower hardy hot landscape pear pink prickly purple spine succulent vegetation water wild wildlife