Kroenleinia grusonii

Kroenleinia grusonii, popularly known as the golden barrel cactus, golden ball, "mother-in-law's cushion" or "mother-in-law’s chair", is a species of barrel cactus which is endemic to east-central Mexico.

The golden barrel cactus is rare and endangered—potentially regionally extinct—in nature. It is native to the Mexican states of Querétaro and Hidalgo, particularly near Mesa de León. Wild populations of K. grusonii were adversely affected in the 1990s as a result of wild specimens being poached as well as the creation of the Zimapán Dam and reservoir (in Hidalgo). The golden barrel cactus is a fairly adaptable species, but naturally prefers growing in rich, volcanic (but well-aerated) soil on sunny slopes, where water quickly flees from its roots. The species may be found growing at altitudes as high as 1,400 metres (4,600 ft) above sea level.