Glossary · Psilocybia

Names and types

Nomenclature

Defined in a standard

The naming of algae, fungi and plants is governed by the International Code of Nomenclature, whose Preamble states that “Biology requires a precise and simple system of nomenclature that is used in all countries, dealing on the one hand with the terms that denote the ranks of taxonomic groups or units, and on the other hand with the scientific names that are applied to the individual taxonomic groups.”

The same Preamble separates naming from classification: “The purpose of giving a name to a taxonomic group is not to indicate its characters or history, but to supply a means of referring to it and to indicate its taxonomic rank.” The Code therefore settles which name is correct for a taxon; it does not settle what that taxon contains. Where accounts on this site record disagreement, it is usually taxonomic rather than nomenclatural.

The current edition is the Madrid Code of 2025, which superseded the Shenzhen Code of 2018. Article numbers cited in this glossary are those of the Madrid Code.

Sources: [icn-madrid-2025] [turland-2025-madrid-code]

Authority

author citation

Defined in a standard

The Code defines an author citation as “A statement of the name(s) of the author(s) responsible for the establishment or introduction of a name; when used, it is appended to that name” (Art. 46 to 50).

In the binomial Psilocybe cubensis (Earle) Singer, the parenthetical author published the basionym and the author outside the parentheses published the combination in its present genus. An authority is a bibliographic fact about the name rather than a statement about the fungus, and two names for the same organism carry different authorities.

Sources: [icn-madrid-2025]

See also: Basionym, Combination, Protologue

Basionym

Defined in a standard

The Code defines a basionym as “The legitimate, previously published name on which a new combination or name at new rank is based. The basionym does not itself have a basionym; it provides the final epithet, name, or stem of the new combination or name at new rank” (Art. 6.10).

When a species is moved to a different genus, the epithet usually travels with it and the original name becomes the basionym of the new combination. This is why the taxonomy section of an account can list a name in one genus and a basionym in another without the two being in conflict.

Sources: [icn-madrid-2025]

See also: Combination, Authority, Epithet

Synonym

Defined in a standard

The Code distinguishes two kinds. A homotypic synonym, also called a nomenclatural synonym, is “A name based on the same type as that of another name (Art. 14.4)”, indicated by the symbol “≡” in the Appendices of the Code. A heterotypic synonym, also called a taxonomic synonym, is “A name based on a type different from that of another name referring to the same taxon (Art. 14.4)”, indicated by the symbol “=”.

The distinction matters when reading an account. A homotypic synonym is a nomenclatural consequence and is not open to opinion: the two names are anchored to the same type specimen. A heterotypic synonym is a taxonomic judgement that a later author may reverse, because it asserts that two differently typified names refer to one taxon. Synonymies given in the accounts are reported from their sources, and where sources disagree the account says so rather than choosing.

Sources: [icn-madrid-2025]

Nomenclatural type

type

Defined in a standard

The Code defines the nomenclatural type as “A specimen, or in some cases an illustration (Art. 8.1), to which the name of a taxon is permanently attached” (Art. 7.2). It adds that “The nomenclatural type of the name of a species or infraspecific taxon is a holotype (Art. 9.1), lectotype (Art. 9.3), neotype (Art. 9.8), or conserved type (Art. 14.9), any of which may be supported by an epitype (Art. 9.9).”

A type is not a representative or typical individual. It is the anchor that fixes the application of a name, which is why a name can only be transferred, synonymised or re-examined by reference to it.

Sources: [icn-madrid-2025]

Holotype

Defined in a standard

The Code defines a holotype as “The one specimen or illustration designated in the protologue as the nomenclatural type of a name of a new species or infraspecific taxon or, when no type was designated, used by the author(s) when preparing the protologue” (Art. 9.1, 9.2, and Note 1).

Accounts record the holotype and its herbarium where a source states them. Where a source does not, the field is left empty rather than inferred from a collection that merely looks like the original material.

Sources: [icn-madrid-2025]

Isotype

Defined in a standard

The Code defines an isotype as “A duplicate specimen of the holotype regardless of whether or not it is cited in the protologue or seen by the author(s) of the name” (Art. 9.5).

Duplicates are commonly distributed to more than one herbarium, so a single gathering can be held in several institutions. An account may therefore cite an isotype at a herbarium other than the one holding the holotype without any inconsistency.

Sources: [icn-madrid-2025]

Protologue

Defined in a standard

The Code defines the protologue as “Everything associated with a name at its valid publication, e.g. description, diagnosis, illustrations, photographs of habitat, references, synonymy, geographical data, citation of specimens, discussion, and comments” (Art. 6.13 footnote).

The protologue is the document a later author returns to in order to decide what a name means. Where an account reports a character “as described in the protologue”, that is a claim about the original publication and not about any specimen examined since.

Sources: [icn-madrid-2025]

Epithet

Defined in a standard

The Code lists epithet among the terms it does not formally define, describing it as “used for the words in a combination other than the generic name and any rank-denoting term; hyphenated words are equivalent to a single word” (Art. 6.7, 11.4, 21.1, 23.1, and 24.1).

It does define the final epithet as “The last epithet in sequence in any particular combination, whether at the rank of a subdivision of a genus, or of a species, or of an infraspecific taxon” (Art. 6.10 footnote). In Psilocybe semilanceata the epithet is semilanceata, and it is that word which usually carries over when a species is moved to another genus.

Sources: [icn-madrid-2025]

Combination

Defined in a standard

The Code defines a combination as “A name of a taxon below the rank of genus, consisting of the name of a genus combined with one or two epithets” (Art. 6.7).

It further provides that “A new combination (combinatio nova, comb. nov.) or name at new rank (status novus, stat. nov.) is a new name based on a legitimate, previously published name, which is the basionym of the new name” (Art. 6.10). Transfers into and out of Psilocybe appear in the accounts as new combinations of this kind, each with its own author and date.

Sources: [icn-madrid-2025]

Records and data

Coordinate uncertainty

Defined in a standard

Darwin Core, the biodiversity data standard used by the occurrence records behind the maps on this site, defines dwc:coordinateUncertaintyInMeters as “A horizontal distance (in meters) from a given dwc:decimalLatitude and dwc:decimalLongitude describing the smallest circle containing the whole of the dcterms:Location. Zero is not a valid value for this term.” The standard directs that the value be left empty where the uncertainty is unknown, cannot be estimated, or does not apply.

A coordinate without an uncertainty is therefore an incomplete georeference rather than a precise one, and GBIF treats the uncertainty as a component of the georeference rather than an optional refinement of it. An occurrence plotted on a map here is a record of where a specimen was reported, carrying whatever uncertainty its own record declares.

Sources: [wieczorek-2012-darwin-core] [chapman-wieczorek-2020-georeferencing]

ITS

internal transcribed spacer

Defined in a standard

Schoch and colleagues, writing for a multinational, multilaboratory consortium, evaluated six DNA regions as candidate barcodes for the fungi and proposed the nuclear ribosomal internal transcribed spacer region as the universal barcode marker for the kingdom.

Most molecular evidence cited in the accounts is ITS sequence data, which is why sequence accessions recorded there are usually ITS. A shared or divergent ITS sequence is evidence about relationships and is not on its own a species delimitation; the accounts report what each study concluded from its own sampling.

Sources: [schoch-2012-its-barcode]

How this reference records evidence

Macroscopic

Usage in this reference

In the description section of each account, macroscopic characters are those observable without magnification: the pileus, the stipe, the lamellae, any veil or annulus, and colour change on bruising.

Macroscopic and microscopic characters are held as separate records, each with its own research state and its own sources. An account can therefore be source-checked for one and unresearched for the other, and the page says which.

Microscopic

Usage in this reference

Microscopic characters are those requiring magnification to observe: basidiospore dimensions and shape, basidia, the cystidia of the gill edge and face, and the structure of the pileipellis and trama.

Measurements are reported as their source gives them, including the ranges and sample sizes that source states. They are not combined across publications into a single figure for the species, because different authors measure different material by different conventions.

Substrate

Usage in this reference

Substrate is recorded in the ecology section as the material a collection was reported from, such as dung, wood debris, or soil in grassland.

Substrates are listed as reported by the sources for that account. A substrate appearing in the list means at least one cited source recorded it, not that the species is restricted to it or that every population uses it.

Provenance

Usage in this reference

In the chemistry records, provenance is what the source states about the material that was actually analysed: its origin, when it was collected and when it was analysed, and any voucher or sequence identifier tying it to a retained specimen.

Provenance is recorded per collection rather than per species, because a published assay measures particular material and not the taxon in general. Where a source does not report an element of provenance, the field is left empty rather than filled from elsewhere in the paper.

Voucher

Usage in this reference

A voucher is the preserved specimen behind a published observation, held in a herbarium or other collection under a citable identifier.

Vouchers are recorded where a source states them and left empty where it does not. The distinction is kept visible because an unvouchered record cannot be checked against the material it describes, whatever else can be said for it.

See also: Provenance, Nomenclatural type, ITS

Analytical method

Usage in this reference

Each assay record keeps the analytical method its source reports, such as high performance liquid chromatography or its ultra high performance variant, together with the detection the source describes.

The method is retained because it bounds what the numbers mean. Figures produced by different methods, on differently prepared material, are not averaged together into a single value for a species; the accounts present the studies separately and say what each one measured.

Measurement basis

dry mass, fresh mass

Usage in this reference

Every assay record states the basis on which its figures are expressed: dry mass, fresh mass, or an extract. Where a source does not report the basis, the record says that instead of assuming one.

The basis has to travel with the number. A concentration by dry mass and the same concentration by fresh mass describe materially different quantities, and a figure whose basis is unreported cannot be compared with either.

References

Chapman, Arthur D.; Wieczorek, John R. (2020). Georeferencing Best Practices. GBIF Secretariat . DOI: 10.15468/doc-gg7h-s853 Source record ↗
Source class: secondary.
Source verification history
- metadata: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Not registered with Crossref; bibliographic record inspected at DataCite. GBIF Secretariat, 2020, creators Chapman and Wieczorek, resource type Text.
- doi: verified · 2026-09-28 · Psilocybia editorial. Verification source
  DOI resolved separately to the GBIF documentation edition 1.0 (en).
- content: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Document retrieved in full and consulted for the treatment of coordinate uncertainty as a required component of a georeference. Cited for that treatment only; no numeric guidance is reproduced here.
Turland, N. J.; Wiersema, J. H.; Barrie, F. R.; Gandhi, K. N.; Gravendyck, J.; Greuter, W.; Hawksworth, D. L.; Herendeen, P. S.; Klopper, R. R.; Knapp, S.; Kusber, W.-H.; Li, D.-Z.; May, T. W.; Monro, A. M.; Prado, J.; Price, M. J.; Smith, G. F.; Zamora, J. C. (2025). International Code of Nomenclature for algae, fungi, and plants (Madrid Code), 2025 Edition. University of Chicago Press . DOI: 10.7208/chicago/9780226839479.001.0001 Source record ↗
Source class: secondary.
Source verification history
- metadata: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Bibliographic identity inspected. Subtitle confirms '2025 Edition, Madrid Code'; monograph, University of Chicago Press; ISBNs 9780226841991, 9780226839462, 9780226839479.
- doi: verified · 2026-09-28 · Psilocybia editorial. Verification source
  DOI resolved separately to the publisher landing record (HTTP 302 to bibliovault ISBN 9780226839479).
- content: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Full text of the Code read in the IAPT online edition. Glossary entries for basionym, author citation, holotype, isotype, nomenclatural type, protologue, epithet, final epithet, homotypic synonym, heterotypic synonym and combination were read directly, together with Preamble 1. Definitions quoted on the glossary page are taken verbatim from those entries with their Article references. The IAPT online edition is cited as the text consulted; the print edition was not collated against it.
Schoch, Conrad L.; Seifert, Keith A.; Huhndorf, Sabine; Robert, Vincent; Spouge, John L.; Levesque, C. André; Chen, Wen; Fungal Barcoding Consortium (2012). Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi. Proceedings of the National Academy of Sciences 109(16), 6241-6246. DOI: 10.1073/pnas.1117018109 Source record ↗
Source class: primary.
Source verification history
- metadata: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Bibliographic identity inspected: PNAS 109(16): 6241-6246, 2012. Crossref lists 158 authors; the record here gives the first seven and the consortium.
- doi: verified · 2026-09-28 · Psilocybia editorial. Verification source
  DOI resolved separately to the PNAS full-text page.
- content: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Abstract read in Europe PMC: six DNA regions evaluated as candidate barcodes for Fungi by a multinational, multilaboratory consortium. Cited at abstract level for the selection of ITS as the marker; the paper's comparative tables were not read and no figures are reproduced.
Turland, Nicholas J. (2025). From the Shenzhen Code to the Madrid Code: New rules and recommendations for naming algae, fungi, and plants. American Journal of Botany 112(4). DOI: 10.1002/ajb2.70026 Source record ↗
Source class: secondary.
Source verification history
- metadata: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Bibliographic identity inspected: American Journal of Botany 112(4), April 2025, single author.
- doi: verified · 2026-09-28 · Psilocybia editorial. Verification source
  DOI resolved separately to the publisher article page.
- content: unavailable · 2026-09-28 · Psilocybia editorial. Verification source
  No abstract or full text retrieved through the indexes consulted here. Cited only for the succession its title reports, namely that the Madrid Code replaced the Shenzhen Code; that succession is independently stated by the IAPT online edition of the Code.
Wieczorek, John; Bloom, David; Guralnick, Robert; Blum, Stan; Döring, Markus; Giovanni, Renato; Robertson, Tim; Vieglais, David (2012). Darwin Core: An Evolving Community-Developed Biodiversity Data Standard. PLoS ONE 7(1), e29715. DOI: 10.1371/journal.pone.0029715 Source record ↗
Source class: primary.
Source verification history
- metadata: verified · 2026-09-28 · Psilocybia editorial. Verification source
  Bibliographic identity inspected: PLoS ONE 7(1) e29715, 2012, eight authors.
- doi: verified · 2026-09-28 · Psilocybia editorial. Verification source
  DOI resolved separately to the PLOS article.
- content: verified · 2026-09-28 · Psilocybia editorial. Verification source
  The normative term record for dwc:coordinateUncertaintyInMeters was read directly in the TDWG Darwin Core quick reference guide, including its definition and notes. The definition quoted on the glossary page is verbatim from that record. The 2012 paper is cited alongside it as the published description of the standard.