Opuntia microdasys irritation so the plants must be treated with caution. The Latin specific epithet "microdasys" means “small and hairy”. The yellow flowers appear only rarely. Despite this, it is a very popular cactus in cultivation, partly because of the young plant’s comical resemblance to a rabbit’s head. It has gained the Royal Horticultural Society’s Award of Garden Merit. The very closely related "Opuntia rufida" differs in having reddish-brown glochids. It occurs further north in northern Mexico, and into western Texas. Some botanists treat the two as a single species. Opuntia microdasys Opuntia microdasys (angel's-wings, bunny ears cactus, bunny cactus or polka-dot
Opuntia arenaria 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 4-7 x 2–3 cm in size. Major spines are found in the distal areoles and are often reflexed, up to 30 mm long. Minor spines are