The genus Aztekium, of the family Cactaceae, is endemic to the state of Nuevo León, Mexico. Aztekium ritteri was discovered by F. Ritter in 1929 near the town of Rayones. For over 72 years this cryptic genus was regarded as monotypic until the discovery of A. hintonii by George S. Hinton, growing in a gypsum canyon less than 40 km away.
Aztekium ritteri is restricted to a valley in Rayones between 700 and 1000 meters above sea level; it grows on vertical conglomerate or gypsum walls. It grows solitary or in clusters, with stems up to 5 cm in diameter, with up to 12 grooved aerole-bearing ribs and smaller secondary ribs in between them. The flowers are white to pink, 8 mm in diameter, arising from the center. Though much sought after for decades its numbers in the wild remain in the millions.
Aztekium hintonii grows on vertical gypsum walls in the municipalities of Galeana and Iturbide, from 1100 to 1900 meters above sea level. It is solitary, to 10 cm in diameter and 15 cm high, with 9 to 12(15) finely grooved ribs, rarely with secondary ribs as those of A. ritteri. The flowers are magenta 1-3 cm in diameter. Although much sought after, its habitat remains mostly undisturbed and its numbers in the wild estimated at 40 million. It shares part of its habitat with Geohintonia mexicana, another genus endemic to the state of Nuevo León.
Pictures by George S. Hinton
