Taxonomy & identification

• Lophophora is a genus of cacti (family Cactaceae) established by John Merle Coulter, published in Contributions from the U.S. National Herbarium 3: 131 (1894); the standard author abbreviation is 'J.M.Coult.' [https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:5395-1; https://en.wikipedia.org/wiki/Lophophora]
• Plants of the World Online (POWO/Kew) recognizes four accepted species in Lophophora: L. alberto-vojtechii, L. diffusa, L. fricii, and L. williamsii. [https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:5395-1]
• The genus name Lophophora means 'crest-bearing', referring to the tufts of hair (wool) borne on each tubercle in place of spines; the genus is placed in subfamily Cactoideae, tribe Cacteae. [https://en.wikipedia.org/wiki/Lophophora]
• Species delimitation within Lophophora is contested: while L. williamsii and L. diffusa are widely accepted, the validity of L. fricii, L. koehresii, and L. alberto-vojtechii as distinct species has been disputed, with some authors treating them as synonyms or infraspecific taxa. [https://en.wikipedia.org/wiki/Lophophora; https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:143598-2]

Phylogenetics — the DNA story

• Per Wikipedia, additional DNA evidence is needed to clarify the status of disputed Lophophora taxa, explicitly L. fricii and L. koehresii (with L. alberto-vojtechii likewise regarded as taxonomically dubious); current sampling has not conclusively confirmed their species status. [https://en.wikipedia.org/wiki/Lophophora]

Habitat

• Lophophora species are small, spineless, button-like succulent geophytes of arid desert and dry shrubland, typically with a large taproot, often growing among nurse/facilitator shrubs in rosetophyllous desert scrub. [https://en.wikipedia.org/wiki/Lophophora; https://www.sciencedirect.com/science/article/abs/pii/S0140196322001197]