Ariocarpus agavoides, found only in six locations in the Mexican states of Tamaulipas and San Luis Potosi, is a diminutive thin tuberculed cacti to 3 inches across. It is one of the smallest species of Ariocarpus. Usually solitary in the wild it will eventually produce offsets in cultivation. It is very rare in the wild due to overcollection and habitat destruction by grazing animals. It produces 1-1/2 inch wide magenta flowers in mid summer. Some specimens like mine have a rare spine or two near the tubercule tips. The typical form is spineless. Mine also has a healthy tuberous root.
     I found this one at Tohono Chul Park and snatched it up immediately because I knew the spines were a rarity. A close up is below. It's still a fairly small specimen so I don't expect flowers anytime soon. Click HERE for a link to a Mark Altenloh page with flower pics. Mark has a pretty extensive collection himself and it's worth spending some time there.