The Beavertail Cactus is found in southwest USA, mostly in the Mojave and Colorado deserts, and also in northwest Mexico. The Beavertail Cactus is a smaller prickly pear cactus growing about 60 cm tall. A single plant may consist of hundreds of fleshy, flattened pads. These are blue-gray, growing to a length of 14 cm and are maximum 10 cm wide and 1 to 1.5 cm thick. They are spineless, but have instead little barbed bristles, called glochids, that easily penetrate the skin. The rose purple flowers bloom from spring to early summer.

There is one subspecies and there are many varieties known to this species:

• Opuntia basilaris subsp. whitneyana
• Opuntia basilaris var. albiflorus
• Opuntia basilaris var. aurea
• Opuntia basilaris var. brachyclada
• Opuntia basilaris var. cordata
• Opuntia basilaris var. heilii
• Opuntia basilaris var. humistrata
• Opuntia basilaris var. longiareolata _ Elongated Beavertail Prickly Pear
• Opuntia basilaris var. ramosa
• Opuntia basilaris var. treleasei _ Trelease's Beavertail Prickly Pear, (California) Bakersfield Cactus Conservation status: Endangered

Some experts consider the Bakersfield Cactus to be a full species (Bowen 1987, R. van de Hoek). This variety is unique among the varieties of Opuntia basilaris in that the eye_spots contain spines in addition to the bristles:

• Opuntia basilaris var. treleasii
• Opuntia basilaris var. whitneyana
• Opuntia basilaris var. woodburyi

This indicates that the species does vary a lot in its exterior.