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, taking around ten years to reach maturity from seed in the wild. Growth can be accelerated considerably in cultivation by grafting. The slow rate of reproduction and over-harvesting render the species under threat in the wild; both L. williamsii and L. diffusa are assessed as Vulnerable on the IUCN Red List.