Four accepted species
Plants of the World Online accepts four species. These are Lophophora alberto-vojtechii, L. diffusa, L. fricii and L. williamsii. John Merle Coulter published the genus in 1894. Older accounts recognised one to five species, depending on the rank assigned to different populations. The name L. koehresii, treated as a separate species in Šnicer and colleagues' account, is now a synonym of L. diffusa in POWO. [2-WWW] [2-WWW] [Šnicer et al. 2009, POWO, as of 10 October 2026. Šnicer et al., pp. 296–297]
The most complete anatomical data in the accounts cited come from L. williamsii. Boke and Anderson studied stem-surface development, while Terry and Mauseth explained underground-organ structure and the basis of regeneration after damage. The expanded description of L. alberto-vojtechii and account of variation in L. fricii mainly provide morphological measurements, seed images and field observations. [Boke and Anderson 1970, Boke and Anderson, pp. 569–577. Šnicer et al., pp. 295–300. Hansen, pp. 225–232] [Šnicer et al. 2009, Boke and Anderson, pp. 569–577. Šnicer et al., pp. 295–300. Hansen, pp. 225–232] [Hansen 2000, Boke and Anderson, pp. 569–577. Šnicer et al., pp. 295–300. Hansen, pp. 225–232] [Terry and Mauseth 2006, Boke and Anderson, pp. 569–577. Šnicer et al., pp. 295–300. Hansen, pp. 225–232]
Above-ground body and underground part
Stems are spherical to flattened, solitary or branched at the base. A photosynthetic crown lies above the substrate surface, and its base passes into an underground stem section and thickened root. Flora del Bajío describes roots as napiform, broad in the upper part and narrowing downwards. The above-ground part may be blue-green, yellowish green or have a reddish tint. Proportions, rib number and hair persistence vary among species. [Arias and Aquino 2019, Flora del Bajío, p. 112. Šnicer et al., pp. 298, 300] [Šnicer et al. 2009, Flora del Bajío, p. 112. Šnicer et al., pp. 298, 300]
Sections of L. williamsii show that the externally visible swelling includes two organs with different anatomy. The underground stem retains areoles and meristems capable of regenerating branches. The root has a different vascular tissue arrangement. The shape of the water-storing part alone therefore does not determine where a new shoot can arise after damage. Detailed data on this regeneration belong to the L. williamsii account. [Terry and Mauseth 2006]
Development of tubercles and areoles
Boke and Anderson followed stem-surface development mainly in material of L. williamsii. Primordia formed spirally on the sides of the apical meristem. In a young tubercle, a vestigial leaf primordium, its expanding base and the bud meristem in the leaf axil jointly formed one complex. Hairs appeared on the side facing the tip, then surrounded the areole meristem. Further growth broadened the tubercles, and their bases merged into low ribs. This developmental description explains the link between tubercle, areole and rib in the plant studied. [Boke and Anderson 1970, p. 571, ryc. 7–18]
The adult stem mainly bears hair tufts. In the L. williamsii seedlings studied, the first tubercles had three to six feathery spines each. In adult individuals, the authors saw primordia that did not develop into spines. Absence of spines on the mature crown therefore results from areole development. In L. alberto-vojtechii, hairs fall off early, so even a mature, flowering plant may have an almost smooth surface. [Boke and Anderson 1970, Boke and Anderson, p. 571. Šnicer et al., pp. 297–298] [Šnicer et al. 2009, Boke and Anderson, p. 571. Šnicer et al., pp. 297–298]
Epidermis and photosynthetic parenchyma
In anatomical material of L. williamsii, the epidermis was covered by a cuticle and wax deposits. Wax was largely responsible for the bluish-green appearance of the northern plants studied. Beneath the epidermis, palisade parenchyma consisting of elongated photosynthetic cells formed as the tubercle matured. The young hypodermis, the layer directly beneath the epidermis, became poorly distinguishable from this parenchyma in adult parts. Large substomatal spaces accompanied the stomata. These are histological results for specific material, rather than a uniform thickness measurement for all four species. [Boke and Anderson 1970, p. 571, 573, ryc. 21, 23–24]
Flowers, fruits and seeds
Flowers arise from areoles of young tubercles near the crown centre. The lower external covering around the ovary, called the pericarpel, and the floral tube are bare, without scales or spines. Tepals take white, pink and red shades. Small stamens surround the style, which ends in a divided stigma. Flower structure and colour differ between species, and some ranges also overlap between populations. [Arias and Aquino 2019, Flora del Bajío, p. 112. Hansen, p. 226–227] [Hansen 2000, Flora del Bajío, p. 112. Hansen, p. 226–227]
Fleshy fruits may be club-shaped or ellipsoidal. They retain dried perianth remains and change consistency during ripening and subsequent drying. Almost spherical, pale fruits were also described in the miniature L. alberto-vojtechii. Black seeds have a distinctly sculptured coat. Electron microscopy compares the shape of its cells, wall convexity and hilum, the scar of seed attachment. These features help assess plant identification together with the flower and material origin. [Arias and Aquino 2019, Flora del Bajío, p. 112. Šnicer et al., pp. 298–299. Hansen, pp. 229–232] [Šnicer et al. 2009, Flora del Bajío, p. 112. Šnicer et al., pp. 298–299. Hansen, pp. 229–232] [Hansen 2000, Flora del Bajío, p. 112. Šnicer et al., pp. 298–299. Hansen, pp. 229–232]
Different places in a dry landscape
POWO gives the range of L. williamsii as southwestern and southern Texas to northeastern Mexico, extending towards Jalisco. It places L. diffusa from Querétaro to Hidalgo, L. fricii in Coahuila and L. alberto-vojtechii in San Luis Potosí. Field accounts show more detailed differences. The miniature species grows on flat alluvial deposits, while L. fricii was described from both plains and limestone terrain. Desert association encompasses different soils, shelters and ways of maintaining the above-ground part near the surface. [2-WWW] [2-WWW] [2-WWW] [2-WWW] [Šnicer et al. 2009, POWO, as of 10 October 2026. Šnicer et al., pp. 297–300] [25-WWW]
Genomy organelli
Sequencing in 2026 provided a new reading of the chloroplast genome of L. diffusa and the first complete assembly of the mitochondrial genome of L. williamsii. The first has 115 689 base pairs and very short inverted repeats. The second comprises 2 422 778 base pairs assembled into five linear sequence representations. Material came from plants intercepted by Chinese customs and maintained in a laboratory. The data describe these specimens and comparisons with available genomes, providing a basis for further studies of population variation. [Zhang et al. 2026, Zhang et al., pp. 676–678. Liu et al., pp. 2–4, 12] [Liu et al. 2026, Zhang et al., pp. 676–678. Liu et al., pp. 2–4, 12]
