The living rock cactus (Ariocarpus fissuratus) is a strange plant, with a large, turnip-like taproot. Its above-ground part consists of a rosette of triangular tubercles which have no spines and which blend in with the stones and rocks on the limestone ledges.
Ariocarpus fissuratus is the only species of this genus that occurs in the USA, although five other species of Ariocarpus are found in the Chihuahuan Desert of mainland Mexico. All are protected plants in the regions where they occur. Many exist as only small, isolated populations and are in danger of extinction because they are sought by plant collectors.
