Psilocybe tampanensis: the 1978 original record, what sclerotia are and why the name confuses

Three different things get blurred together online: a scientific name, the dated collection that name rests on, and the labels attached to material in circulation. For Psilocybe tampanensis the first two can be traced to a four-page paper from 1978 (Guzmán and Pollock, 1978). The third cannot be settled from that paper at all. This guide walks through what the record establishes, defines the word sclerotia in plain terms, and shows where the naming confusion comes from.

What is Psilocybe tampanensis, and who named it?

It is a species in the genus Psilocybe. The Species Fungorum name record, which mirrors the Index Fungorum database kept at the Royal Botanic Gardens, Kew, lists Psilocybe tampanensis Guzmán & S.H. Pollock, published in Mycotaxon 7(2) in 1978, as the current name, with a holotype held at ENCB that Pollock collected on 3 September 1977 in Florida (Species Fungorum). The Global Biodiversity Information Facility (GBIF) lists the same author string with accepted status (GBIF), and Wikidata gives 1978 as the publication date (Wikidata).

The two authors are Gastón Guzmán, a Mexican mycologist who worked at the Escuela Nacional de Ciencias Biológicas in Mexico City, and Steven H. Pollock of the Herbal Medicine Research Foundation in San Antonio, Texas, according to the paper’s own byline (Guzmán and Pollock, 1978; Wikidata, Guzmán).

What does the 1978 original description establish?

The paper is titled “A new bluing species of Psilocybe from Florida, U.S.A.” It says Pollock collected the new species near Tampa during the II International Mycological Congress in September 1977, and its “material examined” entry gives the locality as south-east of Brandon, near Tampa, on 3 September 1977, with the type deposited at ENCB (Guzmán and Pollock, 1978). Those details are the same ones Species Fungorum records, which is what you would expect for a name record.

The paper contains a formal description with both visible and microscopic characters, a note on material studied in culture, and a discussion comparing the new species with two relatives, Psilocybe mexicana and Psilocybe caerulescens. It states that, at the time, the species was known only from the type locality. It also says it precedes a larger monograph on the genus that Guzmán had in preparation (Guzmán and Pollock, 1978). We deliberately do not reproduce the description here: it would turn a naming reference into an identification aid, and that part needs specialist review.

Two limits matter. First, the paper reports no chemical analysis of the type. Its discussion says that, because the new species is close to the other two, it very probably contains psilocin and psilocybin: that is an inference from relatives, not a measurement (Guzmán and Pollock, 1978). Second, a published record is a strong starting point for a history section because a reader can trace the claim to an original document. But it does not document a chain from that one collection to any later sample. That would need additional records, and the 1978 paper does not supply them.

Does the reported appearance help identify a mushroom?

No, and this page keeps it that way. A description in an original paper records the material its authors studied. The 1978 paper itself notes that fruit bodies obtained in culture differed in size from the wild type and from each other (Guzmán and Pollock, 1978), which is a reminder that an appearance statement always belongs to a specific specimen under specific conditions. It is not a checklist that confirms an unknown mushroom. See what are magic mushrooms for the wider picture and our safety page for what to do about a suspected poisoning.

The same caution applies to pictures. A useful reference image would say which material is shown, who identified it, and whether the caption describes a fruiting body or a different fungal structure. An attractive image without that context adds little to an identity claim.

What are sclerotia, and are they a strain name?

A sclerotium (plural sclerotia) is a compact mass of hardened fungal mycelium that contains nutrient reserves (Wang et al., 2025; Wikidata). Mycelium is the thread-like body of a fungus, and the fruiting body, the mushroom, is a different structure. Unrelated fungi form them too, including the ectomycorrhizal fungus Cenococcum geophilum that Wang and colleagues review.

So a sclerotium is a kind of structure, not a species and not a strain. The 1978 paper shows why the distinction matters. It says sclerotia were produced by mycelia in culture and notes that, up to then, sclerotia in Psilocybe had been reported for three named species: P. mexicana, P. caerulescens and P. tampanensis (Guzmán and Pollock, 1978). Its description of the wild type is of a mushroom, and the sclerotia it mentions come from cultured material. A structure, a species name and a product category answer three different questions, and none of them stands in for another.

This article gives no growing, sourcing or consumption information about sclerotia or anything else, and it does not infer legality or safety from the form in which material is described.

Why does the name cause confusion?

The confusion usually comes from treating four separate kinds of statement as one. Keeping them apart is the quickest way to read any claim about this name.

A related trap is the word “Mexicana”. Psilocybe mexicana is a separate scientific name (see our reference on Psilocybe mexicana), and the 1978 paper treats it as a different species that tampanensis resembles but differs from (Guzmán and Pollock, 1978). A name that looks similar, or appears as a label on some material, is not evidence of synonymy.

What happened when a 2025 study checked labels against DNA?

A 2025 paper in Scientific Reports analysed 42 psilocybin-producing fungal strains and cross-checked each one by its ITS (ribosomal DNA) sequence, because it notes that identification by appearance alone may be unreliable. Its methods describe identifying the fungi by appearance, following a published guide, and then matching the sequences against the NCBI database (Cohen et al., 2025).

Several results touch this name. Two entries recorded under the name Psilocybe galindoi were classified as P. tampanensis by their sequences, and the paper’s text says material under the names mexicana, galindoi and tampanensis was classified as tampanensis. Its Table 1 lists nine entries classified as P. tampanensis, and one of them carries the strain name “Mexicana” while already being recorded as tampanensis (Cohen et al., 2025). The text and the table therefore do not line up neatly with a story in which “mexicana was really tampanensis”.

The lesson is about method, not a rule. These are results about particular samples. A database sequence match is not a comparison against the 1977 type specimen, and the study does not claim that every occurrence of a commercial label maps to P. tampanensis. It also does not make the two scientific names synonyms.

For a directory, the useful practice is to record the source label, the scientific identification and the evidence linking them, and to keep any disagreement visible instead of silently replacing the label. Hiding the mismatch would hide the very naming problem the reader is trying to understand. Our guide to names, species, strains and varieties explains the vocabulary.

Does the type collection show where present-day material comes from?

No. A statement that all present material descends from one original collection is much broader than a statement identifying the type collection. The sources used here do not establish that universal genealogy. The 1978 paper mentions that cultures were studied from the type material, but it does not trace any later distribution of cultures to other people or places (Guzmán and Pollock, 1978). Nor does a shared name authenticate a present-day sample against the original material.

A good account can be precise about the 1977 collection and the 1978 publication while leaving later connections unresolved. Our guide to researching origin stories separates collection history, naming history and lineage history, and the same discipline applies here.

What can a species name or type record not tell you?

• How strong any sample is. A species association is not a chemical measurement; see what lab studies do and do not establish.
• Whether a particular mushroom, photograph or product is that species. A type record is not an identification tool.
• Whether a mushroom or other fungal material is safe. A name is not a safety test.
• Anything about a Shroomverse product. Our site uses several product names that echo mushroom names, and a product label is not evidence that any specimen in a record is the material sold.

What this page does not settle

• The full description in the 1978 paper. Held back until a specialist has reviewed it (not covered).
• Family-level placement. Databases disagree (unresolved).
• Whether any present-day material connects to the 1977 type collection, and how (not established by these sources).
• How the 2025 study’s samples were originally labelled and obtained beyond what its methods report (not covered here).

Shroomverse sells mushroom products. This article is general information about mushroom names and taxonomy. It is not medical, legal or identification advice, and it does not recommend any product.