Lophophora diffusa

Lophophora diffusa typically grows as a solitary plant or in groups. Its yellow-green, soft, and somewhat flattened succulent stems reach heights of 2–7 cm (0.79–2.76 in) and diameters of 5–12 cm (2.0–4.7 in). The podaria are rarely elevated, but are broad and flat. The plant lacks ribs, and its wide, flat cusps have small areoles (2–3 mm) with no spines. It has a broad, shallow, tuber-like root, and tufts of hair are unevenly distributed. The flowers are white to slightly pink or yellowish-white, measuring 1.3–2.2 cm (0.51–0.87 in) in diameter.^[5]

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  Plant
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  Flower

This species is the southernmost representative of the genus Lophophora, thriving in limestone soils within a small area of approximately 775 km² (299 sq mi) between Vizarrón, Bucareli, and Tolimán in Querétaro, Mexico, with minor occurrences in Hidalgo. Its natural habitat is semi-deserts on slopes and river beds, and under the shade of various shrubs and nurse plants such as Larrea tridentata and Senegalia sororia.^[4][6] It grows at altitudes of 1,000–2,000 metres (3,280–6,560 ft) above sea level, forming isolated and self-regulated populations in the Estórax River depression.^[7] It is considered vulnerable due to a very small distribution range, small population of less than 3,000 individuals, and illegal collecting. It is collected illegally by people seeking peyote, and as an ornamental plant.^[1]

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  Blooming plant in habitat near Vizarron, Quéretaro, Mexico.
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  Plant growing under scrub in Pena Blanca, Queretaro
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  Cluster of plants growing in Pena Blanca, Queretaro

Originally described as Lophophora echinata var. diffusa by Léon Croizat in 1944, it was elevated to species level in 1967 by Helia Bravo Hollis. The epithet diffusa derives from Latin, meaning "indistinct," referencing the plant's low, flat, and barely noticeable warts.

Lophophora diffusa contains 86% to more than 90% pellotine in terms of total alkaloid content and only trace amounts of mescaline (e.g., 1.2% of alkaloid content), whereas Lophophora williamsii (peyote) contains 30% mescaline and 17% pellotine with regard to total alkaloid content.^{[8][9][10][11]} Mescaline is a psychedelic drug, whereas pellotine is a sedative and hypnotic.^{[8][9][10][11]} However, pellotine was reported in one single study to additionally produce hallucinations at very high doses.^[8][11][12] Further study of Lophophora diffusa and pellotine is needed to confirm or refute the preceding findings.^[8][11]

Lophophora diffusa has reportedly been said to produce effects including feelings of clumsiness, confusion, and general discomfort, or by others a sense of mental clarity or tranquility.^[13] Unlike Lophophora williamsii, it is said to produce no or modest hallucinogenic effects.^[13] However, there have been several reports of Lophophora diffusa producing hallucinogenic effects.^[11] But this may have simply been due to misidentification of the cactus, which may have actually been Lophophora williamsii.^[11] In addition to the preceding, one study reported that Lophophora williamsii produced marked sleepiness but no hallucinogenic effects, which may have been due to misidentification and the cactus actually being Lophophora diffusa.^[8][11][14]

• Lophophora