Opuntia phaeacantha be described as varieties or full species some day. Opuntia phaeacantha Opuntia phaeacantha is a species of prickly pear cactus known by the common names tulip prickly pear and desert prickly pear found across the southwestern United States, lower Great Plains, and northern Mexico. The plant forms dense but localized thickets. Several varieties of this particular species occur, and it also hybridizes easily with other prickly pears, making identification sometimes tricky. "Opuntia phaeacantha" has a characteristic prickly pear appearance, with flattened green pads bearing wool and spines. The spines are brown, reddish-brown, or gray, and often over 3 cm in
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