Opuntia polyacantha for livestock when little other food is available. It will also grow in waste areas where good forage will not take hold. In fact, an abundance of the cactus indicates land that is poor in quality. Several insects attack the cactus, including the cactus moth "Melitara dentata", the blue cactus borer "Olycella subumbrella", and the cactus bug "Chelinidea vittiger". Opuntia polyacantha Opuntia polyacantha is a common species of cactus known by the common names plains pricklypear, hairspine cactus, panhandle pricklypear, and starvation pricklypear. It is native to North America, where it is widespread in Western Canada, the Great Plains, the
Opuntia readily between species. This can make classification difficult, yielding a reticulate phylogeny where different species come together in hybridization. Also, not all species listed here may actually belong in this genus, meaning that "Opuntia" is not a monophyletic group. "Opuntia" also has a tendency for polyploidy. The ancestral diploid state was 2n=22, but many species are hexaploid (6n = 66) or octaploid (8n = 88). Chollas, now recognized to belong to the distinct genus "Cylindropuntia", are distinguished by having cylindrical, rather than flattened, stem segments with large barbed spines. The stem joints of several species, notably the jumping cholla ("Cylindropuntia