Opuntia cespitosa in late spring. This species was historically included in a broadly-defined "Opuntia humifusa" group, which is found further to the east. "Opuntia cespitosa" differs from "Opuntia humifusa" in its flowers having a red center. Opuntia cespitosa Opuntia cespitosa, commonly called the eastern prickly pear, is a species of cactus native to North America. It most common west of the Appalachian Mountains and east of the Mississippi River, where it is found in the Midwest, Upper South and in Ontario. Its natural habitat is in dry, open areas, such as outcrops, glades, and barrens. "Opuntia cespitosa" is a prostrate succulent shrub,
Opuntia dulcis common in trans-Pecos Texas, New Mexico, and Arizona. It has been observed in the mountains of southern Nevada.. Opuntia dulcis Opuntia dulcis has been described as a variety of, and is confused with, "O. phaeacantha". However, "O. dulcis" is a larger plant with ascending branches, to 2 ft (exceptionally 4 ft). While it is a larger plant, immature specimens of O. dulcis may overlap in size with O. phaeacantha. "Opuntia dulcis" resembles "O. engelmannii" in some ways but does not become as erect or large as that species. Also, the spines of "O. dulcis" are finer than those of "O.