Origin and Habitat: Lophophora luteaSN|1749]]SN|1771]] (=Lophophora diffusaSN|1771]]SN|1749]]) is the southernmost population of Lophophora endemic of the of the state of Querétaro, México it grows only in a small area in the hight desert in a valley between Vizarron, Bucareli, and Toliman (Extent of occurrence about 300 km²). L. diffusa occurs at the south end of the range of the genus.
Altitude: It grows at an elevations of 1,300 to 1,800 metres above sea level.
Habitat and Ecology: Driest and stoniest desert Xerophytic shrubland, on calcareous soils where the soil is deep enough to allow the tuberous root to grow. L. diffusa grows mainly beneath the canopy of some locally dominant shrub and possible nurse plant (e.g. Larrea tridentata and Acacia sororia). The species is threatened by illegal collecting and use by indigenous people for medicine, and by collectors for ornamental trade.

• Lophophora lutea (Rouhier) Backeb.
• Lophophora echinata var. lutea (Rouhier) Croizat
• Lophophora williamsii var. lutea (Rouhier) Soulaire
• Lophophora williamsii var. luteus Rouhier

• Lophophora diffusa (Croizat) Bravo
• Lophophora echinata var. diffusa Croizat
• Lophophora williamsii subs. diffusa (Croizat) Scheinvar
• Lophophora williamsii var. diffusa (Croizat) G.D.Rowley
• Peyotl diffusus (Croizat) Sotom., Arred. & Mart.Mend.
• Lophophora diffusa var. koehresii Říha
• Lophophora koehresii (Říha) Bohata, Myšák & Šnicer
• Lophophora viridescens (Halda) Halda
• Lophophora williamsii var. koehresii (Říha) Grym
• Lophophora diffusa subs. kubesae Halda, Kupčák & Malina
• Lophophora diffusa subsp. kubesai Halda, Kupčák & Malina
• Lophophora diffusa var. swobodaiana Halda, Kupčák & Malina
• Lophophora diffusa subs. viridescens Halda
• Peyotl viridescens (Halda) Sotom., Arred. & Mart.Mend.
• Lophophora lutea (Rouhier) Backeb.
• Lophophora echinata var. lutea (Rouhier) Croizat
• Lophophora williamsii var. lutea (Rouhier) Soulaire
• Lophophora williamsii var. luteus Rouhier

Description: Lophophora luteaSN|1117]]SN|1771]] (= Lophophora diffusaSN|1749]]SN|1749]]) is a globular spineless cactus with large tap root. Solitary or forming variable stemmed clumps with few stems or sometime large mounded group with several heads. This is the more primitive species of Lophophora. It is rare in cultivation:
Stem: 2-7 cm tall, 5-12 cm in diameter (some population have larger stems up to 20-25 cm in diameter), yellow-green or grey-green, usually lacking well-defined ribs and furrows.
Ribs: 5 to 13 the podaria are rarely elevated, wavy, broad and flat.
Areoles: With tufts of hairs that usually spread unequally on the prominent podaria.
Flowers: Commonly whitish to yellowish-white, 1,5-3 centimetres in diameter.
Note: Lophophora luteaSN|1771]]SN|1771]] (= Lophophora diffusaSN|1749]]SN|1749]]) is geographically isolated, but questionably distinct from Lophophora williamsiiSN|1771]]SN|1117]].

Bibliography: Major references and further lectures
1) Gómez-Hinostrosa, C., Sánchez , E., Guadalupe Martínez, J. & Terry, M. 2013. Lophophora diffusa. In: IUCN 2013. “IUCN Red List of Threatened Species.” Version 2013.2. <www.iucnredlist.org>. Downloaded on 24 February 2014 .
2) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
3) 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
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
5) Edward F. Anderson “Peyote: The Divine Cactus” University of Arizona Press, 1996

Cultivation and Propagation: Slow growing Requires half shade in summer, full sun the rest of the year.
Grow it in a narrow and deep container to accommodate the tap root, they are very rot prone, so use highly gritty compost with much drainage.
Waterings should be rather infrequent to keep the plant compact and not to become excessively elongated and unnatural in appearance, watering it properly is often difficult because this plant tends to crack open or rot if over-watered. The fact that the plant retracts into the soil and assume a grey-green colouring between watering, is perfectly natural and doesn’t cause any damage.
Like other arid zone cacti, they require a dry and cool over-wintering otherwise they may succumb to rot. It also promotes flowering. Assure a good ventilation.
Propagation: Seeds.
Seed should be sown in spring in sterile cacti mix. Cover with a humidity dome or plastic wrap and leave in a warm spot in 50-75% shade. Fluctuating temperatures are best (ie. high day temperature and low night temperature) as they simulate the desert environment.
Keep constantly humid as seedlings cannot survive if to dry. Seedlings will emerge in 7-21 days and can be grown in the same environment for a number of months. Mulch with thin layer of small quartz gravel (1-2mm diameter) this helps them stay upright, hinders algae growth and regulates moisture. As they get older the watering can become less frequent. Potting up can be done when 5-10mm in diameter.