Opuntia macrorhiza Opuntia macrorhiza Opuntia macrorhiza is a common and widespread species of cactus with the common names plains prickly pear or twistspine pricklypear or Western pricklypear. It is found throughout the Great Plains of the United States, from Texas to Minnesota, as well as in the desert and Rocky Mountain states from Arizona to Idaho, with sporadic populations in the Mississippi and Ohio Valleys. It is also reported from northern Mexico, in the states of Chihuahua, Sonora, Coahuila, Nuevo León, Durango, Tamaulipas, and San Luís Potosí. The species is cultivated as an ornamental in other locations. The species prefers dry, sandy
Opuntia ovaries per carpel. Placentation is parietal, and the fruit is a berry with arillate seeds. Prickly pear species can vary greatly in habit; most are shrubs, but some, such as "Opuntia echios" of the Galápagos, are trees. "O. ficus-indica" thrives in regions with mild winters having a prolonged dry spell followed by hot summers with occasional rain and relatively low humidity. A mean annual rainfall of provides good growth rates. "O. ficus-indica" proliferates in various soils ranging from sub-acid to sub-alkaline, with clay content not exceeding 15-20% and the soil well-drained. The shallow root system enables the plant to grow