Opuntia engelmannii Opuntia engelmannii Opuntia engelmannii is a prickly pear common across the south-central and Southwestern United States and northern Mexico. It goes by a variety of common names, including cow's tongue cactus, cow tongue prickly pear, desert prickly pear, discus prickly pear, Engelmann's prickly pear, and Texas prickly pear in the US, and nopal, abrojo, joconostle, and vela de coyote in Mexico. The nomenclatural history of this species is somewhat complicated due to the varieties, as well as its habit of hybridizing with "Opuntia phaeacantha". The "Opuntia engelmannii" range extends from California to Louisiana in the United States, and from Sonora
Opuntia fragilis in). Both the common and scientific names refer to the easily detached stem segments. This is known to be a means of plant dispersal. "Opuntia fragilis" is a small, prostrate plant, rarely more than 4 inches high: joints tumid, fragile, easily detached, oval, elliptical, or subglobose, 1-2 in. long and nearly as thick as broad, bright green: areoles ¼-½ in. apart, with whitish wool and a few white to yellow bristles, which are much longer and more abundant on older joints; spines 1-4, occasionally a few small additional ones, weak, dark brown, the upper one usually longer and stronger than