Proboscidea althaeifolia (devil's claw, unicorn plant) ( )

Among our showiest desert annuals, but relatively uncommon is devil's claw. This unusual member of the unicorn-plant family also utilizes C₄ metabolism and thus summer flowering. Devil's claw is a brilliant, yellow-flowered perennial. It has a sprawling growth form with large, moist, and sticky-lobed leaves. The large bilaterally symmetrical flowers, up to 1½ inch across, look like those of jacaranda and other flowers in the related bignon family (Bignoniaceae). It is a perennial with a stout tap root that prefers dunes. The origin of the rather sinister name devil's claw is because of the long, woody capsules, up to 3-4 inches in length, which split open at one end to form a pair of curved claws. These claws readily cling to the hooves of grazing animals, or your shoes if you are not watching where you step. Since these claws don't fit the hooves of native grazing animals, scientists have speculated that this form evolved to facilitate dispersal by giant ground sloths and other Pleistocene megafauna that are now extinct. "California Desert Plants, Philip W Rundel, Robert J Gustafson, Michael E Kauffmann."
This plant sprawls along the ground and resembles a squash vine. It sports showy pink or yellow trumpet-shaped blossoms that produce a seedpod with long, curved hooks that easily attach to shoes or hooves. The seed itself is covered in smaller, sharp spines. "Wicked Plants, Amy Stewart."