:: Ariocarpus retusus ssp retusus -- This species is the largest of the genus, capable of reaching 25cm in diameter.  It is divided into two sub-species, ssp retusus and ssp trigonus.  The Ariocarpus retusus ssp retusus may be found in many areas of San Louis Potosi and Nuevo Leon.

Along with the Ariocarpus fissuratus, it is commonly called a 'living rock', due to its mimicry of its habitat.  Consequently, specimens slightly vary morphologically depending on their habitat.  Generally, the Ariocarpus retusus ssp retusus is characterized by long, pyramidal tubercles formed densely, varying from light to dark green in colour.  Most frequently tubercles are smooth, however minor wrinkling is visible in some forms.  The Ariocarpus retusus ssp retusus produces large diurnal white flowers. ::

Ariocarpus retusus ssp retusus

:: Ariocarpus bravoanus ssp hintonii

TAnother relatively new inclusion in the Ariocarpus genus.  The hintonii was originally included in the fissuratus species and was named after George Hinton, who discovered it.  The plant is endangered and may be found in only two locations in the state of San Louis Potosi.  The plant is characterized by generally shorter tubercles than the bravoanus sub-species and very distinct lateral grooves on the tubercles.  The Ariocarpus bravoanus ssp hintonii produces large pinkish flowers.. ::

Ariocarpus bravoanus ssp hintonii