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 engelmannii (state) to the Tamaulipan matorral in Chihuahua (state), in Mexico. In the Sonoran Desert, terminal pads face predominantly east-west, so as to maximize the absorption of solar radiation during summer rains. Although found occasionally in the Mojave Desert, it tends to be replaced by "Opuntia basilaris", which does not need the summer rain. The overall form of "Opuntia engelmannii" is generally shrubby, with dense clumps up to high, usually with no apparent trunk. The pads are green (rarely blue-green), obovate to round, about 15–30 cm long and 12–20 cm wide. The glochids are yellow initially, then brown with age. Spines