Mammillaria hahniana is a beautiful member of the Mammillaria genus and one that forms large clumping groups. It is easily identified by its long white hairs, which can densely cloak the plant's body and increase in thickness, richness and length in age. This cactus flowers prolifically, even when young. Native to the central Mexican states of Guanajuato, San Luis Potosí, and Queretaro, where it's range is extremely limited, thus making it relatively endangered in the wild. Mature specimen, many heads.