I grow several forms and varieties of O. basilaris. The beavertail cactus is native to the Mojave and Sonoran deserts to about to 6,000 feet. The blue-gray 10inch long pads are shaped like a beaver's tail. Dense clusters of brown glochids are it's main defence.the flowers are hot pink/magenta. The fruits are dry and pearshaped. Mature clumps can get to be two foot tall and three to four foot across.
http://plants.usda.gov/java/profile?symbol=OPBA2
http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Opuntia+ba...
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242413847
Here are a couple of patches of Opuntia basilaris var. basilaris I have.
