Opuntia engelmannii particular, classified the fruits by color, time of ripening, and how well they kept in storage. "Opuntia engelmannii" is cultivated as an ornamental plant, for use in drought tolerant gardens, container plantings, and natural landscaping projects. Master Gardeners of the University of Arizona Pima County Cooperative Extension — "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
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