Britton and Rose, Smithsonian Miscellaneous Collections 50: 532, 1908
Opuntia covillei is a medium-sized plant that grows in angular shapes. Areoles have 4-8 whitish spines. The plants often grow in impenetrable thickets 2- to 3-ft tall. It grows at the base of Mt. San Bernardio, Mt. Baldy, Mt. Gorgonio and into the desert foothills near Banning. The bright yellow flowers are large for a plant of this size. The stigma is green. Unlike many CA opuntias, O. covillei grows in inland valleys. O. covillei seems to be the same as O. megacarpa, which was described around the same time. However, the name, O. covillei, has precedence. See the original description. Ploidy is unknown.