Psilocybe quebecensis: the psilocybin mushroom named from Quebec, and what became of the name

Psilocybe quebecensis is often described online as Canada’s own magic mushroom: a psilocybin species first named from Quebec. The name is real and dates from 1967, but the main fungal name databases no longer treat it as a separate species (Species Fungorum; GBIF). This article traces what the records say, how rarely the name has been used since, and what DNA work has done to the few specimens that carry it.

What is Psilocybe quebecensis?

It is a scientific name in the genus Psilocybe, the genus that holds most of the fungi people call magic mushrooms. The full name with its authors is Psilocybe quebecensis Ola'h & R. Heim. Species Fungorum, the name database kept at the Royal Botanic Gardens, Kew, gives the locality as Québec and the publication as Naturaliste canadien 94: 574 (1967) (Species Fungorum, record 337863). The epithet quebecensis simply marks the place the material came from.

The same record lists the current name as Psilocybe aztecorum R. Heim, a species Heim published in 1957 in the Revue de Mycologie from México State (Species Fungorum, P. aztecorum). GBIF, the Global Biodiversity Information Facility, agrees: its backbone taxonomy files P. quebecensis as a synonym and points to P. aztecorum as the accepted name (GBIF). The iNaturalist taxon search sends the name to P. aztecorum too (iNaturalist API). Not every database has merged it: the NCBI sequence database still files its DNA records under Psilocybe quebecensis (NCBI).

In plain terms, a synonym is a second name for what a database treats as one species. It is a judgement, and judgements change when new evidence arrives. Our guide to names, species and strains explains the vocabulary, and the species and names directory lists the main Psilocybe names side by side.

How, where and when was Psilocybe quebecensis described?

The name was published twice in 1967, and the databases treat the two publications differently. The first was a short note in the Comptes rendus of the French Academy of Sciences, series D, volume 264, pages 1601 to 1604, dated March 1967. Its French title announces a new North American species of hallucinogenic Psilocybe (Europe PMC record). Species Fungorum lists this version with the comment “Nom. inval., Art. 39.1 (Melbourne)”: the name as published there does not meet a rule of the botanical code (Species Fungorum, record 633450).

The second was in Le Naturaliste canadien, volume 94, page 574, also in 1967. Index Fungorum marks this record as legitimate, and it is the citation GBIF carries in its “published in” field (Index Fungorum web service; GBIF). We could not open the Code article Species Fungorum cites, and we could not open either 1967 paper, so we do not explain the technical fault in the first note. The practical result is simple: the Naturaliste canadien paper is the one the databases treat as the valid publication.

The two authors were Roger Heim, the French mycologist who had already named several Mexican Psilocybe species, including P. aztecorum, and G. M. Ola'h (also written Oláh). Ola'h went on to publish a study of the species’ fine structure in Mycopathologia et Mycologia Applicata in 1973, pages 321 to 338 (Oláh, 1973). We could read only that paper’s bibliographic record, not its text.

A living culture survives. The Westerdijk Institute’s CBS collection in the Netherlands holds strain CBS 165.67, marked as type material, and its GBIF record carries the note “G.M. Olah, 28 Sep 1966” (GBIF, CBS record). The ITS DNA barcode sequenced from that culture is in GenBank as NR_160108, labelled “from TYPE material” and geo-located to “Canada: Quebec” (NCBI). The record does not say whether the 1966 date is the collection date or the date the culture was made.

What did the early chemistry report?

Less than people assume, as far as we could check. The title of the 1967 Comptes rendus note calls the species hallucinogenic (Europe PMC record), but we could not open the note, so we cannot say what analysis it reports, which compounds it names, or how they were measured. A 1976 short communication by Steven Pollock in Drug and Alcohol Dependence cites the 1967 note in a list of references for Psilocybe species “demonstrated to contain” psilocybin and/or psilocin (Pollock, 1976). That is a later author’s citation, not the measurement itself.

We found no modern chemical analysis of material identified as P. quebecensis in the full-text literature we searched through Europe PMC: the only Psilocybe papers there that mention the name are the 1967 note, the 1973 fine-structure paper and the 2024 genome study discussed below (Bradshaw et al., 2024). The genome study looked for psilocybin genes, not for psilocybin itself. For why measured strength varies so much even within a well-studied species, see our page on what lab studies do and do not establish.

How often has Psilocybe quebecensis been recorded since 1967?

Very rarely. On 24 October 2026 GBIF held 15 records filed under the name Psilocybe quebecensis worldwide. Ten carry the country code for Canada and none the United States; the other five, mostly culture-collection and DNA-sequence entries, name no country. Of the ten Canadian records, six are from Quebec, one from Newfoundland and Labrador and one from Ontario, and two give no province. Seven are preserved herbarium specimens, and the dated ones run from 1979 to 1995.

Small numbers like these are fragile. One Quebec specimen record in the Université de Montréal’s mycologists’ fungarium notes that its database date (1995) and its label date (1985) disagree, and that the specimen may not be the one in the database (GBIF, CMMF record). A single correction can move a count by a large share. Records also show where a name was written down, not how common a fungus is; our Canada-wide records guide explains why collector effort shapes these maps.

Because GBIF folds the name into P. aztecorum, its species page for P. aztecorum shows these records too. Counted with its synonyms, P. aztecorum had 205 GBIF records on 24 October 2026: 68 from the United States, 64 from Mexico and 32 from Canada. Anyone reading a Canadian total for P. aztecorum should know that part of it is material originally filed as P. quebecensis.

What did the 2024 genome study find about a P. quebecensis specimen?

A 2024 study in the Proceedings of the National Academy of Sciences sequenced genomes from Psilocybe specimens to build a family tree of the genus and trace the psilocybin gene cluster. The authors found four specimens that sat with the wrong group in their trees. One was a specimen labelled “Psilocybe quebecensis”, catalogue NY1901130 at the New York Botanical Garden herbarium. After re-examining the specimens under the microscope, they redetermined it as Psilocybe caerulipes (Bradshaw et al., 2024).

That specimen appears to be the only Ontario record in the GBIF count above. The GBIF entry is a New York Botanical Garden specimen with catalogue number 01901130, collected and identified by O. K. Miller in Ontario in 1995, and on 24 October 2026 it was still filed as P. quebecensis (GBIF, NY record). Databases do not always catch up with a published redetermination. The lesson for readers is to treat any single record as a claim about one specimen, checked by one person at one time.

The 2024 study does not discuss the name P. quebecensis beyond that one specimen, and it does not test the synonymy with P. aztecorum (Bradshaw et al., 2024). P. caerulipes is a different and older name, first published by Charles Peck in 1885 from New York (Species Fungorum). Our Ontario records guide covers the P. caerulipes records in that province.

What did the 2022 DNA study show about mislabelled Psilocybe specimens?

Two years earlier, an overlapping team re-examined 94 Psilocybe herbarium specimens from 18 species by DNA barcoding. Their abstract says that, apart from a few well-known species, the names on specimens were “largely unreliable, even at the genus level”, and that public sequence databases hold many poor-quality or mislabelled sequences (Bradshaw et al., 2022). The paper does not mention P. quebecensis.

One point in it bears directly on this name. The authors write that only five species of Psilocybe in the strict sense were represented by ITS barcodes derived from types, and that the best-known species, such as P. cubensis, had none (Bradshaw et al., 2022). P. quebecensis is unusual in having a type-derived ITS sequence on record, from the CBS culture, generated in a large barcoding project of the CBS collection (NCBI). We did not check whether it was one of the five the 2022 paper counted, or whether anyone has yet compared it with type material of P. aztecorum.

How does Psilocybe quebecensis compare with P. caerulipes and P. cubensis?

The table compares naming facts only: who described each name, when, where the original material came from, how the name stands now and how many GBIF records it has in Canada and the United States. It deliberately leaves out any feature that could be used to tell the mushrooms apart. The counts were read from the GBIF occurrence API on 24 October 2026 (GBIF).

Read the record counts as how often a name was written down and shared, not how common anything is. The P. cubensis figures, for example, include cultivated and community-posted material, and Canada’s five P. cubensis records are a tiny share of its 1,147 US records (GBIF). Our P. cubensis naming history goes through that name in detail.

Is Psilocybe quebecensis legal in Canada?

The law does not name mushroom species. Schedule III of the federal Controlled Drugs and Substances Act lists psilocin and psilocybin, each “and any salt thereof”, at items 11 and 12, and section 2(2) says a reference to a controlled substance includes any substance that contains one (Justice Laws, CDSA). Whatever a mushroom is called, the chemicals are what the Act controls. Our guide to whether magic mushrooms are legal in Canada covers the offences, exemptions and recent changes.

What we don't know about Psilocybe quebecensis

• What the 1967 papers report. We could not open either the Comptes rendus note or the Naturaliste canadien paper, so their descriptions and any chemistry are unread.
• Who first treated P. quebecensis as a synonym of P. aztecorum, and on what evidence. The databases record the synonymy but do not cite its source on the pages we read; Guzmán’s 1978 Mycologia paper on P. aztecorum may discuss it, but the publisher page refused our request.
• Whether the synonymy holds up in DNA. We found no published comparison of the type-derived P. quebecensis sequence with type material of P. aztecorum.
• How many of the other herbarium specimens filed as P. quebecensis would survive re-examination. Only one has been checked in print, and it turned out to be P. caerulipes.
• What any material called P. quebecensis contains chemically today. We found no modern analysis.

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