Opuntia robusta Opuntia robusta Opuntia robusta, the wheel cactus, nopal tapon, or camuesa, is a species of cactus in the Cactaceae family. It is native and endemic to central and northern Mexico to within 100 miles of the Arizona and New Mexico borders where it grow from 5,000 to 10,000 feet on rocky slopes, open shrub lands, woodlands and mixed with other cactus and succulents. Plants are commonly around high, though they may grow to over high when supported. The flattened stem segments are fleshy, round and blue-grey in colour. These are up to in diameter and have sharp spines up to
Opuntia basilaris These are more or less blue-gray, depending on variety, long and less than wide and thick. They are typically spineless, but have instead many small barbed bristles, called glochids, that easily penetrate the skin. "Opuntia basilaris" blooms from spring to early summer. The species is variable in nature and several names under different ranks have been described. Only four of these are generally accepted. Some experts consider the Trelease's beavertail to be a full species (Bowen 1987, R. van de Hoek). It is unique among the varieties of "Opuntia basilaris" in that the areoles contain spines in addition to the