An independent scientific referenceTaxonomy · Evidence · Context
PSILOCYBIAA monograph for the digital age.
Research edition Accounts distinguish source checks from human review. Research coverage is incomplete. Read our standards

Psilocybia / The Index / Species record

The Psilocybe Index / Species account

Psilocybe samuiensis

Guzmán, Bandala & J. W. Allen

Taxonomy: acceptedChemistry: Not yet researchedMolecular data: Not yet researched

Scoped source check. Original 1993 description, comprehensive synonymy, chemistry, molecular literature, conservation, scientific imagery and occurrence datasets remain unchecked. Source-specific morphology and collection-label differences are retained without resolution.

01Overview

Source-checked

This scoped account compares two published treatments of the Thai holotype, covering selected morphology, habitat and collection provenance. Original-description coverage and the broader literature review remain incomplete. [ramirez-cruz-2013-types] [guzman-2012-thailand]

This is a scientific reference record, not field-identification guidance.

02Nomenclature

Accepted name
Psilocybe samuiensis
Authority
Guzmán, Bandala & J. W. Allen
Family
Agrocybaceae
Publication year
1993
Basionym
Not yet researched — verification required
Taxonomic status
accepted
MycoBank identifier
Not yet researched — verification required
Index Fungorum identifier
Not yet researched — verification required
Synonyms (0 recorded names)

No verified synonyms entered. This does not indicate that synonyms do not exist.

Nomenclatural sources: [gbif-5459370-2026] [ramirez-cruz-2013-types] [guzman-2012-thailand] [niskanen-2026]

Research completeness

taxonomy
Human reviewed — J Dale, 2026-09-29

Name and primary type treatment checked; family classification reconciled. Comprehensive synonymy review remains pending.

overview
preliminary

Selected passages checked; coverage is incomplete.

description
preliminary

Selected passages checked in the 2012 treatment and 2013 holotype revision. Coverage remains incomplete; measurements and collection labels retain their source-specific notation.

ecology
preliminary

Selected passages checked in the 2012 treatment and 2013 holotype revision. Coverage remains incomplete; measurements and collection labels retain their source-specific notation.

distribution
disputed

Selected passages checked in the 2012 treatment and 2013 holotype revision. Coverage remains incomplete; measurements and collection labels retain their source-specific notation.

chemistry
not researched

Not researched for this account; no absence claim.

molecular
not researched

Not researched for this account; no absence claim.

history
preliminary

Selected passages checked; coverage is incomplete.

conservation
not researched

Not researched for this account; no absence claim.

03Taxonomic description

Taxonomic description. These characters are presented for scientific reference and are not intended as field-identification guidance.

Macroscopic characters

Source-checked

The 2012 treatment reports a pileus 7–15 mm across, adnexed lamellae and a stipe 40–65 × 1.5–2 mm, without an annulus. These are selected characters from that treatment; the original 1993 description has not been inspected here. [guzman-2012-thailand]

Microscopic characters

Source-checked

The 2013 holotype study reports spores 9.6–12.0 × 6.4–8.4 × 5.6–7.2 µm, hexagonal to subrhomboid in frontal view and ellipsoid to elongate in lateral view; pleurocystidia 14.5–22 × 4–6.5 µm; and an ixocutis. The 2012 treatment gives spores 10–13 × 6–8 µm and pleurocystidia 16–20 × 5–6.5 µm. These overlapping measurements remain source-specific; no pooled range or third spore dimension is inferred for the 2012 account. [ramirez-cruz-2013-types] [guzman-2012-thailand]

04Distribution and ecology

Disputed

Both treatments place the XAL holotype collection 2 km west of Ban Hua Thanon on Ko Samui, Thailand, on 8 August 1991. The 2013 study labels it J. Allen F; the 2012 treatment uses Allen s.n. The differing collector designations are retained without equating them to a verified accession number. This locality documents examined material and does not define the full range. [ramirez-cruz-2013-types] [guzman-2012-thailand]

Known range
Thailand, reported as known only from that country
Countries with documented material
Thailand
Habitats
Meadows on rich soil, Rice paddies
Substrates
Rich soil
Ecological associations
Not yet researched
Seasonality
Not yet researched

Ecological context

Source-checked

The holotype study records scattered to gregarious growth in rice paddies. The 2012 treatment describes rich meadow soil, citing the original description. These are source-reported habitat observations, not a comprehensive ecological profile. [ramirez-cruz-2013-types] [guzman-2012-thailand]

Occurrence records

21 georeferenced records, shown as 16 distinct positions at this scale. Records carry 2 country codes. Full-precision records are available from the citable source dataset.

Recorded observations are not equivalent to true biological range. Absence of records does not demonstrate absence of a species.

Occurrence provenance & map methods
Licence / retrieval date
CC BY-NC 4.0 / 2026-09-15
Coordinate uncertainty
Reported for 12 of 21 plotted records. Median 29 km; 1 records at 30 m or finer; coarsest 30 km. Points are plotted at source precision, so precision varies by orders of magnitude within this map.
Sensitive records
unreviewed
Countries with georeferenced records
AU (13) · TH (8)

Points are plotted at source precision on an equirectangular projection. Two records falling on the same rendered pixel appear as one mark; the downloadable dataset is not reduced. Records published under names this reference has not reconciled, including synonyms, infraspecific taxa and sequence clusters, are excluded rather than reassigned.

05Chemistry

Measurements belong to studies, specimens and methods. A single concentration cannot stand in for a species.

Published assays · Measurements retain their original methodological context.
Study / yearMaterialMethodRecord
No verified assay records entered. This does not establish that no published assays exist.
Fields retained in each future assay record

Study, publication year, specimen, material, sample size, provenance, analytical method, preparation, storage, psilocybin, psilocin, baeocystin, norbaeocystin, aeruginascin, units, qualifiers and methodological notes. No concentrations have been invented for this prototype.

Modern quantitative assays

Not yet researched

Modern analytical studies have not yet been systematically searched and checked for this account.

Evidence assessment

Not yet researched

Chemical literature has not yet been reviewed for this account. No assay values are extracted; this does not establish compound presence or absence.

Assessments depend on material, preparation, storage, sampling and analytical methods. Measurements are literature records, not predictions of effects.

How chemistry records are structured ↗

06Molecular evidence

Not yet researched

Species-specific molecular findings have not yet been checked for this account; no sequence or phylogenetic claim is extracted.

07History

Source-checked

The name was published in Mycotaxon 46:156 (1993), as cited by both revisions and GBIF. The 2013 study adds observations on pileus-trama arrangement and caulocystidia. The original paper remains unchecked here. [ramirez-cruz-2013-types] [guzman-2012-thailand] [gbif-5459370-2026]

A place for the historical record

This account records the nomenclatural history checked so far. Broader historical research remains pending; interpretations must stay connected to their documentary sources.

Reading the scientific record ↗

08Conservation

Not yet researched

Conservation assessments have not yet been researched for this account.

Assessment status
Not yet researched
Assessment authority / year
Not verified / Not verified

Not researched by Psilocybia, not assessed by a conservation authority, and Least Concern are different states. None should be inferred from another.

09Images & specimens

No verified, licensed scientific images supplied

Space is reserved for field photographs, herbarium specimens, microscopy and historical plates, with source and licence metadata.

Photographs are not presented as sufficient for mushroom identification.

10References

  1. GBIF Secretariat (2026). Psilocybe samuiensis — GBIF Backbone Taxonomy record 5459370; accessed 14 September 2026. . Source record ↗

    Source class: taxonomic database.

    Source verification history
    • metadata: verified · 2026-09-14 · Psilocybia editorial. Verification source

      Full API name record inspected: nomenclature, species rank, acceptance and older family placement. lastInterpreted is in 2023; retrieval is not a new taxonomic revision.

    • content: verified · 2026-09-14 · Psilocybia editorial. Verification source

      Full API name record inspected: nomenclature, species rank, acceptance and older family placement. lastInterpreted is in 2023; retrieval is not a new taxonomic revision.

  2. GBIF.org (2026). GBIF Occurrence Download: georeferenced records for Psilocybe taxa (download 0000371-260915150036944). . DOI: 10.15468/dl.dhgzxa Source record ↗

    Source class: primary.

    Source verification history
    • metadata: verified · 2026-09-29 · Psilocybia editorial. Verification source

      Download record retrieved from the GBIF API. Key 0000371-260915150036944, DOI 10.15468/dl.dhgzxa, status SUCCEEDED, created 2026-09-15, 31,439 records drawn from 294 datasets, SIMPLE_CSV format, licence http://creativecommons.org/licenses/by-nc/4.0/legalcode. The DOI and the record count were confirmed against the archive held locally rather than assumed from the filename.

    • doi: verified · 2026-09-29 · Psilocybia editorial. Verification source

      DOI read from the download record returned by the GBIF API and matched to the download key of the archive used to generate the occurrence maps.

    • content: verified · 2026-09-29 · Psilocybia editorial. Verification source

      The archive was read row by row to generate the published maps and the per-country counts. 31,208 rows carry usable coordinates and a taxonKey this reference maps to one of its own records; 231 rows fall under synonyms, infraspecific taxa or sequence clusters and are excluded rather than reassigned. Coordinate uncertainty is reported for about 90 per cent of rows, with a median near 7 km and a coarsest value above 5,000 km, so individual points vary enormously in precision. 25 per cent of the country entries derived from this download rest on a single record, and the majority of records are human observations rather than preserved specimens; counts are therefore published alongside every country.

  3. Gastón Guzmán; Florencia Ramírez Guillén; Kevin D. Hyde; Samantha C. Karunarathna (2012). Psilocybe s.s. in Thailand: four new species and a review of previously recorded species. Mycotaxon 119, 65–81. DOI: 10.5248/119.65 Source record ↗

    Source class: primary.

    Source verification history
    • metadata: verified · 2026-09-14 · Psilocybia editorial. Verification source

      Full PDF title page and Crossref title, authors, volume, pages and DOI matched. Selected samuiensis treatment on p. 69 inspected; measurements checked against page image. Original 1993 paper not inspected.

    • content: verified · 2026-09-14 · Psilocybia editorial. Verification source

      Full PDF title page and Crossref title, authors, volume, pages and DOI matched. Selected samuiensis treatment on p. 69 inspected; measurements checked against page image. Original 1993 paper not inspected.

    • doi: verified · 2026-09-14 · Psilocybia editorial. Verification source

      Full PDF title page and Crossref title, authors, volume, pages and DOI matched. Selected samuiensis treatment on p. 69 inspected; measurements checked against page image. Original 1993 paper not inspected.

  4. iNaturalist (2026). Psilocybe samuiensis — iNaturalist taxon 518957; accessed 29 September 2026. . Source record ↗

    Source class: taxonomic database.

    Source verification history
    • metadata: verified · 2026-09-29 · Psilocybia editorial. Verification source

      Taxon record retrieved and confirmed by two independent routes: a name query returned exactly one active species taxon named Psilocybe samuiensis with id 518957, and the record endpoint was then fetched directly and agreed on name, rank and active status. This is an identifier for a community observation platform, not a taxonomic authority.

    • content: verified · 2026-09-29 · Psilocybia editorial. Verification source

      Taxon record retrieved and confirmed by two independent routes: a name query returned exactly one active species taxon named Psilocybe samuiensis with id 518957, and the record endpoint was then fetched directly and agreed on name, rank and active status. This is an identifier for a community observation platform, not a taxonomic authority.

  5. T. Niskanen; B. Dentinger; A.M. Ainsworth; I. Kytövuori; J.T. Kim; G.W. Griffith; K. Liimatainen (2026). Re-shaping the family-level classification of Agaricineae (Agaricales, Basidiomycota) using a phylogenomic approach. Studies in Mycology 113(1), 115–134. DOI: 10.3114/sim.2026.113.03 Source record ↗

    Source class: primary.

    Source verification history
    • metadata: verified · 2026-09-10 · Psilocybia editorial. Verification source

      Bibliographic identity inspected; publication year is distinct from retrieval date.

    • content: verified · 2026-09-10 · Psilocybia editorial. Verification source

      Family treatment Agrocybaceae, Table 1 and classification discussion inspected in the PDF. Effective online date in paper: 1 April 2026; Crossref issue date differs, so the record retains year only.

    • doi: verified · 2026-09-10 · Psilocybia editorial. Verification source

      DOI and title matched against the cited bibliographic record; not just resolver availability.

  6. Virginia Ramírez-Cruz; Gaston Guzmán; Laura Guzmán-Dávalos (2013). Type studies of Psilocybe sensu lato (Strophariaceae, Agaricales). Sydowia 65(2), 277–319. Source record ↗

    Source class: primary.

    Source verification history
    • metadata: verified · 2026-09-10 · Psilocybia editorial. Verification source

      Bibliographic identity checked against the publication.

    • content: verified · 2026-09-10 · Psilocybia editorial. Verification source

      Full PDF inspected, with goniospora pp. 291–292 and ovoideocystidiata pp. 302–303 read in detail. No numeric microdimensions transcribed because extracted unit glyphs are unreliable. Qualitative cystidial observations and the type voucher are used.

Claim provenance

Source checks record what was inspected. Publication approval and section review are separate editorial decisions.

Name, authorship and original publication citation checked in the type revision and GBIF name record.

Fields: taxonomy.canonical_name, taxonomy.accepted_name, taxonomy.genus, taxonomy.specific_epithet, taxonomy.authority, taxonomy.publication_year

Species retained in the type revision and corroborated by GBIF acceptance; comprehensive synonymy review remains pending.

Fields: taxonomy.status

Follow the 2026 family treatment, which includes Psilocybe in Agrocybaceae.

Fields: taxonomy.family

GBIF retains Hymenogastraceae in a record interpreted in 2023.

Fields: taxonomy.family

  • gbif-5459370-2026 — family, lastInterpreted

    Source checked · Accessed 2026-09-14 · Psilocybia editorial. Selected source passage inspected. Quantitative type passages checked against PDF page images.

This scoped account compares two published treatments of the Thai holotype, covering selected morphology, habitat and collection provenance. Original-description coverage and the broader literature review remain incomplete.

Fields: overview.text

The 2012 treatment reports a pileus 7–15 mm across, adnexed lamellae and a stipe 40–65 × 1.5–2 mm, without an annulus. These are selected characters from that treatment; the original 1993 description has not been inspected here.

Fields: description.macroscopic.text

The 2013 holotype study reports spores 9.6–12.0 × 6.4–8.4 × 5.6–7.2 µm, hexagonal to subrhomboid in frontal view and ellipsoid to elongate in lateral view; pleurocystidia 14.5–22 × 4–6.5 µm; and an ixocutis. The 2012 treatment gives spores 10–13 × 6–8 µm and pleurocystidia 16–20 × 5–6.5 µm. These overlapping measurements remain source-specific; no pooled range or third spore dimension is inferred for the 2012 account.

Fields: description.microscopic.text

The holotype study records scattered to gregarious growth in rice paddies. The 2012 treatment describes rich meadow soil, citing the original description. These are source-reported habitat observations, not a comprehensive ecological profile.

Fields: ecology.narrative.text

Both treatments place the XAL holotype collection 2 km west of Ban Hua Thanon on Ko Samui, Thailand, on 8 August 1991. The 2013 study labels it J. Allen F; the 2012 treatment uses Allen s.n. The differing collector designations are retained without equating them to a verified accession number. This locality documents examined material and does not define the full range.

Fields: distribution.narrative.text

The name was published in Mycotaxon 46:156 (1993), as cited by both revisions and GBIF. The 2013 study adds observations on pileus-trama arrangement and caulocystidia. The original paper remains unchecked here.

Fields: history.text

The 2012 treatment lists Allen s.n. (holotype XAL).

Fields: distribution.narrative.text

The 2013 treatment lists J. Allen F (XAL, holotype).

Fields: distribution.narrative.text

21 georeferenced records for this name in the cited GBIF download, plotted as 16 distinct positions and spanning 2 country codes, of which 0 rest on a single record. These are record locations, not a compiled range: no range has been researched for this account.

Fields: distribution.occurrence

Database identifiers for this species, recorded so a reader can retrieve the same records. The GBIF backbone still places Psilocybe in Hymenogastraceae, whereas this site follows the 2026 family revision and treats the genus in Agrocybaceae; citing the identifier is not an endorsement of that placement.

Fields: distribution.gbif_taxon_id, distribution.inaturalist_taxon_id

The 2012 review reports the species as growing on rich soil in meadows; the type study records the holotype as gregarious to scattered in rice paddies.

Fields: ecology.habitats, ecology.substrates

The 2012 review states the species is known only from Thailand. Both papers cite the Ko Samui holotype.

Fields: distribution.regions, distribution.countries

Conflicting evidence

Resolved: taxonomy.family

The database retains an older family placement.

Adopt Niskanen et al. (2026) for family placement; use GBIF to corroborate nomenclature and acceptance. — Psilocybia editorial, 2026-09-14

Unresolved: distribution.narrative.text

The two treatments report the same locality, date and holotype herbarium but different collector designations. The specimen label has not been independently inspected.