Psilocybe cubensis: name, discovery and closest relatives

The 1906 description from Cuba

Earle published the species in the first annual report of the Estación Central Agronómica de Cuba, the agricultural research station at Santiago de las Vegas that Earle set up and directed from 1904, in a paper on Cuban fungi. The name appears on page 240 of that report as Stropharia cubensis (GBIF name record). The epithet cubensis means "from Cuba" and refers to the place the type material came from. The genus name Psilocybe comes from Greek and means "bare head", a reference to the smooth cap.

Stropharia was a reasonable first choice. Species in that genus also have dark spores and a ring on the stem, and in 1906 nothing was known about the chemistry that later became the defining feature of this group.

From Stropharia to Psilocybe

Singer transferred the species to Psilocybe in the journal Sydowia, volume 2, which is dated 1948. Some sources give 1949, the year the volume circulated. The full scientific name, Psilocybe cubensis (Earle) Singer, keeps both names: the author in brackets described the species, the author outside the brackets gave it its current genus.

Synonyms: one species, several names

Before mycologists compared the collections, the same mushroom was described more than once, from places far apart. The GBIF backbone taxonomy lists these names as synonyms of P. cubensis:

The two varieties were based on small differences in cap colour between the Florida, Indochina and Cuban collections. They are formal names, published with a description, which makes them a different kind of name from the cultivar labels in the strain index. Current databases list them as synonyms of the species.

Where the species comes from

P. cubensis grows on the dung of cattle and other large grazing animals, which makes its history tied to livestock. A 2026 study in Proceedings of the Royal Society B summarised the long-standing view: the mushroom was carried to the Americas with cattle from Africa and Europe from around 1500 onwards, while its ancestor lived in Africa (Bradshaw et al., 2026).

The same study sequenced DNA from type specimens of all accessible African Psilocybe species. African collections that had been filed as P. cubensis turned out to be a distinct species, now named Psilocybe ochraceocentrata. According to the molecular clock analysis, the two species last shared an ancestor about 1.5 million years ago, with a 95% interval of roughly 710,000 to 2.55 million years. That is long before cattle were domesticated. Both species grow on the dung of large herbivores, and the authors suggest this habit made P. cubensis well placed to follow domestic cattle.

Wild populations and cultivated lines

A 2023 genome study in Current Biology compared 38 wild isolates from Australia with 86 commercially available cultivars (McTaggart et al., 2023). The Australian mushrooms, linked to accidental poisonings there since the 1940s, form a naturalised population: introduced at some point, they passed through a bottleneck and have since regained relatively high genetic diversity. The cultivars showed the opposite pattern, with low diversity, low heterozygosity and signs of selfing and clonal propagation. Most cultivars descend from related populations.

In other words, the species is genetically varied in the wild, and the cultivated part of it is a narrow, inbred slice. How that slice is divided into named strains is explained on what a strain name means.

Where it sits in the genus

Psilocybe contains many species that produce psilocybin, from the small liberty cap of European grassland to tropical species of Mexico and South-East Asia. P. cubensis stands out among them for a practical reason: the McKenna brothers' grower's guide of the 1970s already described it as one of the easiest of these mushrooms to cultivate, and most strain names in the mushroom trade today are names for lines of this one species. The Dutch Opium Act names it on List II, in a list of dozens of Psilocybe species and other psilocybin-producing fungi (Opium Act).

For what the mushroom looks like and where it grows today, see morphology and habitat.