Maihueniopsis

I obtained this species from C and D Plants. It is interesting not only for the coloration of the plant (purplish-green) and its flowers...Read More (ranging from reddish-brown through cherry or blood red to purplish-red) but for its fruits, which are edible and said to be sweet-tasting; and also for its being self-fertile, a very, very rare characteristic within the Cactaceae-- almost all cacti being what are called "obligate outcrossers", requiring fertilization by a genetically distinct clone to set fruit. M. nigrispina will set fruit even when fertilized by its own pollen, or so it's claimed. When I coax mine into to bloom, I will find out if it really does so and report back.

Another synonym is Platyopuntia atroglobosa.
The leaves on Maihueniopsis's are very small and fall off early.