Low-growing, usually yellow-green cactus from the Chihuahuan Desert of northern Mexico with pointy, often incurved tubercles projecting above ground level. Usually a few inches in diameter. Flowers are yellow or cream.

This is the only Ariocarpus species to occur (in part) outside the Chihuahuan Desert. Found in Tamaulipas, Hidalgo, and Nuevo León. Central Tamaulipas is the easternmost extent of the genus.

Ariocarpus trigonus is considered by some taxonomists as a subspecies of A. retusus, but is geographically disjunct, with differences in color, tubercles, and flower color. Intermediate forms between the two species are known to exist.

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