Familiar to many cactus collectors, opuntia microdasys
is native to Mexico but has become established in the wild in some parts of central Arizona, 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.