Origin and Habitat: Restricted to a small area in the Cerritos and Villa Juárez Municipalities, San Luis Potosi, México. There are six known disjunct subpopulations of Turbinicarpus laui, which are distributed over an area of 250 km² (extent of occurrence) and add up to an area of occupancy of less than 5 km².
Altitude: It grows at about 1,000 m asl.
Habitat and Ecology: This cactus grows in semi-desert (Chihuahuan Desert, although not typical) among bare areas with Helieta parvifolia and Ptelea trifoliata as neighboring vegetation. It occurs on gypsum-calcareous or gypsum soils. One of the localities is characterized by massive, dark-colored limestone rocks. The habitat is locally classified as matorral submontano. The population of about 4,000 mature individuals is severely fragmented and is suffering from a continuing decline due to illegal collecting and fires.

• Turbinicarpus laui Glass & R.A.Foster
• Neolloydia laui (Glass & R.A.Foster) E.F.Anderson
• Pediocactus laui (Glass & R.A.Foster) Halda
• Strombocactus laui (Glass & R.A.Foster) Mays

Description: Turbinicarpus laui is a tiny solitary, flattened globose cactus. Some hobbyists refer to the genus as Gymnocactus.
Stem: Sub-globose to depressed globose, up to 35 mm wide and up to 15 mm tall.
Ribs: Divided into tubercles, arranged in 5 and 8 spirals with 3 or 4 tubercles per spiral, dull medium green, up to 5 mm high, rhomboidal and up to 10 mm wide at base, conoidal.
Areoles: About 1 mm long, copiously woolly with thick, long, white wool in youth, soon becoming bare
Spines: 6 to 7, and occasionally with an additional upper (sub-central) spine, glassy white with blackish tip, slender acicular, relatively stiff and slightly recurved, spreading, radiating; lower three spines up to 5 mm long, upper lateral spines up to 7 mm long, upper spine (s) ca. 18-22 mm long and generally incurved, connivent over the top of the stem, or occasionally erect to somewhat tortuous;
Flowers: White or pink, 35 mm wide, ca. 18 to 25 mm long; perianth segments with a slightly darker pale pink or pale tan middle-stripe; outer segments with a brownish middle-stripe on the outer surface; style white to pale cerise with 3 to 6 whitish stigma lobes which overtop anthers; stamens numerous with pale cerise filaments and golden yellow anthers, the longest to about 12 mm long.
Fruit: Small, round, greenish to brown, ca 5 mm in diameter, dehiscent by a longitudinal slit
Seed: 1.1 mm long, tuberculate, black.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
3) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
4) Fitz Maurice, W.A., Sotomayor, M., Smith, M. & Fitz Maurice, B 2013. Turbinicarpus laui. In: IUCN 2013. "IUCN Red List of Threatened Species." Version 2013.2. <www.iucnredlist.org>. Downloaded on 18 February 2014.

Cultivation and Propagation: It’s quite prone to rot, especially after the first flowering. Needs a well-drained soil. Watering should be rather infrequent, but abundant, so that the soil becomes completely soaked. The fact that the plant retracts into the soil, and assumes a grey-green colouring between waterings, is perfectly natural and doesn’t cause any damage. Keep dry in winter or when night temperatures remain below 10° C. It is hardy to -4°C for a short period. Assure a good ventilation.
Exposure: Full sun where it obtains a flat natural looking aspect, or part sun.