:: 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