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 arenaria strongly deflexed and much shorter. Overall, plants (clumps) of cladodes may be 20–30 cm across and about 4–8 cm tall. Fruits are small, about 2.5 cm. Opuntia arenaria Opuntia arenaria was considered a variety of "O. polyacantha" by many botanists, and is still treated that way in the Flora of North America. However, "O. arenaria" is diploid and "O. polyacantha" is tetraploid. It was described by Engelmann in 1856. "Opuntia arenaria" can grow in soil that is essentially pure sand. It has rhizomes up to 1.5 m long that give rise to above ground shoots with small cladodes that are