Etymology -This unusual genus was named by F. Boedeker in 1929 because the colour of the rock-like body and the lateral very distinctive ribs are said to be reminiscent of original designs in the sculptures of the early Aztek Indians.
Two species make up the genus Aztekium that were discovered over 60 years apart. Despite this gap in discovery, the two species clearly belong in the same genus. Both grow on vertical or near-vertical gypsum cliffs where little else will grow. They grow in the Mexican state of Nuevo Leon in separate populations; each in a single valley. With such limited distribution, these extreme survivors need serious protection to keep from becoming extinct in the wild due to illegal collecting.
Both species are star shaped. A. ritteri which was discovered first, has rounded ribs with many transverse wrinkles making even young plants look ancient. A. hintonii on the other hand has much more acute or distinct ribs with more uniform cross banding on the ribs. Spines are not prominent on either species. Both species are fairly small, with stems not exceeding 4 inches in diameter and typically are half that size. A. hintonii stays solitary, while A. ritteri tends to form clumps when older. Flowers are dainty and loose, arising from the apex of the plant. Hintonii has dark pink flowers and ritteri has white flowers with a faint pink stripe.
Because of the limited distribution and the unusual growth habits of this genus, it is much sought after by experienced cacti enthusiasts. However, it is especially slow-growing and not especially easy to grow. As a result, most plants in cultivation are grafted specimens that survive on a much hardier root stock.