Lophophora

Lophophora is a genus of spineless, button-like cacti. Its native range covers Texas through Mexico to southwestern Mexico. The species are extremely slow growing, sometimes taking up to thirty years to reach flowering age (at the size of about a golf ball, excluding the root) in the wild. Cultivated specimens grow considerably faster, usually taking between three and ten years to reach from seedling to mature flowering adult. The slow rate of reproduction and over-harvesting by collectors render the species under threat in the wild.

Taxonomy
Lophophora means "crest-bearing", referring to the tufts of trichomes that adorn each tubercle. Lophophora has been reported to have two species, L. diffusa and L. williamsii. Another three species have been proposed: L. fricii, L. koehresii, and L. alberto-vojtechii. Recent DNA sequencing studies (Butterworth et al. 2002) have shown that L. diffusa and L. williamsii indeed are distinct species. DNA evidence from the alleged species L. fricii and L. koehresii would allow for more accurate classification.

Species
, Plants of the World Online accepted four species:

Cultivation
Lophophora species easily adapt to cultivation, requiring warm conditions and a free-draining substrate, and to be kept dry in winter.