Ariocarpus retusus subsp. trigonus LRM170

The plants of A. trigonus in the San Antonio area are of the 'elongatus' type, and often occur in more open locations than the more westerly colonies. At this location the plants occur in association with Obregonia denegrii, but generally inhabit the higher, more exposed areas, Obregonia being more prevalent in the protection of bushes at lower levels.