Aztekium

About

The genus Aztekium contains two species of small globular cactus. Collected in 1929 by F. Ritter, in Rayones, Nuevo León, Mexico, this genus was thought to be monotypic until a second species was identified by George S. Hinton, in Galeana, Nuevo León in 1991. A further possible species, Aztekium valdezii, was described in 2011, but is considered to be a synonym of A. ritteri.

Summary from Wikipedia