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....read more on Wikipedia.