Familiar to many cactus collectors, opuntia microdasys
is native to Mexico but has become established in the wild in some parts of central Arizona, and a few other urban locations, as well as being extensively used as a decorative landscaping plant. The species is related to opuntia rufida
of west Texas, being completely spineless, the closely-spaced areoles instead bearing large tufts of glochids, usually pure white, and very easily detached.
The bright green pads are oval in shape, longest dimension about 4 inches, and the plant forms extensive, fast-growing clusters, of dozens or even hundreds of stem segments, mostly expanding sideways rather than vertically.