T. bicolor and its current (2013) botanically accepted subspecies bolaensis, flavidispinus, heterochromus and schwarzii having the widest distribution. In contrast, one species, T. lausseri, only occurs in one known remote locality in central Coahuila state. Species are distributed in mountainous stony/rocky places or grassy territory with clay soil. Cultivation Thelocactus species are generally easy to cultivate, even if many species fail to flower until they are five years old. Soils should be composed of equal proportions of sand and humus. Water normally from Spring to Autumn. In Winter, keep most species at a minimum temperature of 8 °C. They can survive at lower temperatures but the roots then must be kept dry. The dark brown or black seeds can be relatively large for the size of cactus and they germinate readily. Reproduction is nearly always from seed, since the plant rarely produces plantlets. The seed should be put in a sand and compost mixture, kept moist, maintained at a temperature of 21 °C and placed in a shady position. Thelocactus bicolor has gained the Royal Horticultural Society's Award of Garden Merit. Synonymy The following genera have been brought to synonymy with Thelocactus: Hamatocactus Britton & Rose This genus contained 8 species and was known from the Southwest United States and in northern Mexico. The name Hamatocactus means "hooked cactus" in Latin. Thelomastus Fric (nom. inval.) Species Species recognized by International Cactaceae Systematics Group. (Anderson E. F., 2001) Formerly placed here Turbinicarpus beguinii (N.P.Taylor) Mosco & Zanov. (as T. beguinii N.P.Taylor) Turbinicarpus gielsdorfianus <small>(Werderm.) V.John & Ríha (as T. gielsdorfianus (Werderm.) Borg) Turbinicarpus horripilus (Lem.) V.John & Ríha (as T. horripilus (Lem.) Kladiwa) Turbinicarpus knuthianus (Boed.) V.John & Ríha (as T. knuthianus (Boed.) Borg) Turbinicarpus lophophoroides (Werderm.) Buxb. & Backeb. (as T. lophophoroides Werderm.) Turbinicarpus mandragora (Fric ex A.Berger) A.D.Zimm. (as T. mandragora A.Berger) Turbinicarpus pseudopectinatus (Backeb.) Glass & R.A.Foster (as T. pseudopectinatus (Backeb.) E.F.Anderson & Boke) Turbinicarpus saueri (Boed.) V.John & Ríha (as T. saueri (Boed.) Borg) Turbinicarpus subterraneus (Backeb.) A.D.Zimm. (as T. subterraneus (Backeb.) Backeb. & F.M.Knuth) Turbinicarpus viereckii (Werderm.) V.John & Ríha (as T. viereckii (Werderm.) Bravo) Turbinicarpus ysabelae (Schlange) V.John & Ríha (as T. ysabelae Schlange) References This article has been expanded using, inter alia, material based on a translation of an article from the Swedish Wikipedia, by the same name. It has also been augmented by material translated from the Italian Wikipedia. Literature Edward F. Anderson: