Essential ICN Rules (Madrid Code) to Know

Reference:

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 Señoret, J.C. 2025. International Code of Nomenclature for algae, fungi, and plants (Madrid Code). Regnum Vegetabile 162. Chicago: University of Chicago Press.

https://www.iaptglobal.org/_functions/code/madrid

DEFINITION OF TERMS IN ICN (MADRID CODE)

Analysis: A figure or group of figures, often presented separately from the main illustration of the organism (though usually on the same page or plate), showing details aiding identification, with or without a separate caption (Art. 38.10; see also Art. 38.11).

Available name: A name published under the International Code of Zoological Nomenclature with a status equivalent to that of a validly published name under the International Code of Nomenclature for algae, fungi, and plants (Art. 45 Ex. 1 footnote).

Basionym: 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) (see also name at new rank, new combination).

Binding decision: A recommendation made by the General Committee and ratified by an International Botanical Congress on (1) whether or not a name is validly published (Art. 38.5) or (2) whether or not names are to be treated as homonyms (Art. 53.4) (see also Art. 20 Note 1). Binding decisions are listed in (1) App. VI or (2) App. VII.

Binomial (binary combination): A generic name combined with a specific epithet to form a species name (Art. 23.1) (see also combination).

Combination: 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).

Conserved name (nomen conservandum): (1) A name of a family, genus, or species, or in certain cases a name of a subdivision of a genus or of an infraspecific taxon, declared legitimate, even though it may have been illegitimate when published, and taking precedence over other specified names even if it lacks priority (Art. 14.1–14.7, 14.10, App. II, III, and IV). (2) A name for which the type, orthography, or gender has been determined by the conservation process (Art. 14.8, 14.9, 14.11, App. III, and IV) (see also protected name).

Conserved type (typus conservandus): A type attached to a name by the conservation process (Art. 14.8 and 14.9) to serve as the nomenclatural type when it would otherwise not be the type under Art. 7–10, 40, and F.5.4 (see also nomenclatural type).

Correct name: The name that must be adopted in accordance with the rules for a taxon with a particular circumscription, position, and rank (Art. 6.6, 11.1, 11.3, and 11.4)

Date of name: The date of valid publication of a name (Art. 33.1).

Description: A statement explicitly describing one or more features of an individual taxon. A description need not be diagnostic (Art. 38.4). It may include morphological, anatomical, biochemical, karyological, molecular, or similar features of the taxon but cannot serve as a validating description if it describes only properties such as those listed in Art. 38.3. Note that a description or a diagnosis is required for valid publication of a name of a new taxon (Art. 38.1(a)). A name, by itself, may convey some descriptive information about the taxon to which it is applied but is not sufficient to serve as a description or a diagnosis (see also diagnosis).

Descriptive name: A name of a taxon above the rank of family not formed from a generic name (Art. 16.1(b)).

Designation: [Not defined] – the term used for what appears to be a name but that (1) has not been validly published and hence is not a name in the sense of the Code (Art. 6.3) or (2) is not to be regarded as a name (Art. 20.4 and 23.7) (see also binary designation, type designation).

Diagnosis: A statement of properties that in the opinion of its author distinguishes a taxon from other taxa (Art. 38.2). Note that a diagnosis or a description is required for valid publication of a name of a new taxon (Art. 38.1(a)) (see also description).

Effective publication: Publication in accordance with Art. 29–31 (Art. 6.1).

Epithet: [Not defined] – 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; see also Art. H.10.2) (see also final epithet).

Figure: See analysis.

Final epithet: 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).

Fossil-taxon: A taxon (diatom taxa excepted) the name of which is based on a fossil type (Art. 1.2 and 13.3).

Gathering: Material collected by the same collector(s) at the same time from a single locality and presumed to be of a single taxon (Art. 8.2 footnote; see also Art. 8 Note 1) (see also duplicate).

Holotype: 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) (see also nomenclatural type).

Homonym: A name spelled exactly like another name published for a taxon at the same rank based on a different type (Art. 53.1). Note that names of subdivisions of the same genus or of infraspecific taxa within the same species that are based on different types and have the same final epithet are homonyms, even if they differ in rank (Art. 53.3), because the rank-denoting term is not part of the name (Art. 21 Note 1 and Art. 24 Note 2) (see also confusingly similar names).

Illegitimate name: A validly published name that is not in accordance with specified rules (Art. 6.4), principally those on superfluity (Art. 52) and homonymy (Art. 53 and 54) (see also homonym, superfluous name).

Illustration: A work of art or a photograph depicting a feature or features of a species or infraspecific taxon, e.g. a drawing, a picture of a herbarium specimen, or a scanning or transmission electron micrograph, but not a photograph of habitat (Art. 6.1 footnote).

Improper Latin termination: A termination of a name or epithet not in accordance with the termination required by the Code (Art. 16.3, 18.4, 19.7, and 32.2).

Indelible autograph: Handwritten material reproduced by some mechanical or graphic process (such as lithography, offset, or metallic etching) (Art. 30.6).

Indirect reference. A clear (if cryptic) indication, by an author citation or in some other way, that a previously and effectively published description or diagnosis applies (Art. 38.15) or that a basionym or replaced synonym exists (Art. 41.3).

Lectotype: One specimen or illustration designated from the original material as the nomenclatural type, in conformity with Art. 9.11 and 9.12, if the name was published without a holotype, or if the holotype is lost or destroyed, or if a type is found to belong to more than one taxon (Art. 9.3) (see also nomenclatural type).

Legitimate name: A validly published name that is in accordance with the rules, i.e. one that is not illegitimate (Art. 6.5) (see also illegitimate name).

Monotypic genus. A genus for which a single binomial is validly published (Art. 38.7).

Name: A name that has been validly published, whether it is legitimate or illegitimate (Art. 6.3) (see also designation).

Neotype: A specimen or illustration selected to serve as the nomenclatural type if no original material exists or as long as it is missing (Art. 9.8 and 9.13; see also Art. 9.16 and 9.19) (see also nomenclatural type).

Nomen conservandum (nom. cons.): See conserved name.

Nomen novum (nom. nov.): See replacement name.

Nomen nudum (nom. nud.): A designation of a new taxon published without a description or diagnosis or reference to a description or diagnosis (Art. 38 Ex. 1, Rec. 50B) (see description, designation, diagnosis).

Nomen rejiciendum (nom. rej.): A name rejected in favour of a name conserved under Art. 14 or a name ruled as rejected under Art. 56 (App. IIA, III, IV, and V) (see also nomen utique rejiciendum, rejected name).

Nomen sanctionatum (nom. sanct.): See sanctioned name.

Nomenclatural type: A specimen, or in some cases an illustration (Art. 8.1), to which the name of a taxon is permanently attached (Art. 7.2). 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).

Non-fossil taxon. A taxon the name of which is based on a non-fossil type (Art. 13.3).

Nothogenus: A hybrid genus (Art. 3.2).

Original material: The set of specimens and illustrations from which a lectotype may be chosen (see Art. 9.4, Art. 9 Notes 2–5, Art. F.3.10, and Art. F.3 Note 2 for details), or the holotype (see Art. 9.1).

Page reference: Citation of the page or pages on which the basionym or replaced synonym was validly published or on which the protologue appears (Art. 41 Note 1; see also Art. 41 Note 2 and Rec. 41A.2).

Paratype: Any specimen cited in the protologue that is neither the holotype nor an isotype, nor one of the syntypes if in the protologue two or more specimens were simultaneously designated as types (Art. 9.7).

Priority: A right to precedence established by the date of valid publication of a legitimate name (Art. 11) or of an earlier homonym (Art. 53 Note 4), or by the date of designation of a type (Art. 7.10, 7.11, and F.5.4).

Pro synonymo (pro syn., as synonym): A citation indicating that a name or a designation is merely cited as a synonym (Art. 36.1(b) and Rec. 50A) (see designation).

Protected name: The name of an organism treated as a fungus listed (in App. IIA, III, or IV) with its type and treated as conserved against any competing listed or unlisted synonyms or homonyms (including sanctioned names), although conservation under Art. 14 overrides this protection (Art. F.2.1) (see also conserved name).

Protologue: 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).

Provisional name: A designation proposed in anticipation of the future acceptance of the taxon concerned, or of a particular circumscription, position, or rank of the taxon (Art. 36.1(a)) (see designation).

Rank: [Not defined] – used for the relative position of a taxon in the taxonomic hierarchy (Art. 2.1). For suprageneric names published on or after 1 January 1887, the rank is indicated by the termination of the name (see Art. 37.2 and footnote). For names published on or after 1 January 1953, a clear indication of the rank is required for valid publication (Art. 37.1).

Rejected name: A name ruled as not to be used, either by formal action under Art. 14, 56, or F.7 overriding other provisions of the Code (see nomen rejiciendum, nomen utique rejiciendum) or because it was nomenclaturally superfluous when published (Art. 52) or a later homonym (Art. 53 and 54). A name treated as rejected under Art. F.7 may become eligible for use by conservation under Art. 14.

Replaced synonym: The legitimate or illegitimate, previously published name on which a replacement name (nomen novum) is based. The replaced synonym, when legitimate, does not provide the final epithet, name, or stem of the replacement name (Art. 6.11) (see replacement name).

Replacement name (nomen novum): A new name published as an explicit substitute (avowed substitute) for a legitimate or illegitimate, previously published name, which is its replaced synonym and which, when legitimate, does not provide the final epithet, name, or stem of the replacement name (Art. 6.11 and 7.4; for names not explicitly proposed as substitutes see Art. 6.12 and 6.13) (see replaced synonym).

Sanctioned name (nomen sanctionatum): The name of a fungus treated as if conserved against earlier homonyms and competing synonyms, through acceptance in a sanctioning work (Art. F.3.1).

Specimen: A gathering, or part of a gathering, of a single species or infraspecific taxon, disregarding admixtures, mounted either as a single preparation or as more than one preparation with the parts clearly labelled as being part of the same specimen or having a single, original label in common (Art. 8.2 and 8.3; for fossil-taxa see Art. 8.6). A specimen may not be a living organism or an active culture (Art. 8.4) (see gathering).

Subdivision of a family: Any taxon at a rank between and not including family and genus (Art. 4 Note 2).

Subdivision of a genus: Any taxon at a rank between and not including genus and species (Art. 4 Note 2).

Superfluous name: A name that, when published, was applied to a taxon that, as circumscribed by its author, definitely included the type of a name that ought to have been adopted, or of which the epithet ought to have been adopted, under the rules (Art. 52.1). A superfluous name is illegitimate except as provided by Art. 52.4 or unless conserved (Art. 14), protected (Art. F.2), or sanctioned (Art. F.3).superseded. [Not defined] – used for a designation of a type that is not followed but is replaced by a subsequent designation of a different type under the provisions of Art. 9.15, 9.18, 9.19, 10.2, or 10.5.

Synonym: [Not defined] – one of two or more names that apply to the same taxon. Also used in the sense of a name that applies to a taxon but is not the correct name for that taxon (see heterotypic synonym, homotypic synonym).

Syntype: Any specimen cited in the protologue when there is no holotype, or any of two or more specimens simultaneously designated in the protologue as types (Art. 9.6). Illustrations cannot be syntypes.

Tautonym: A binary designation in which the specific epithet exactly repeats the generic name (Art. 23.4).

Taxon (taxa): A taxonomic group at any rank (Art. 1.1).

Validly published: Effectively published and in accordance with the relevant provisions of Art. 32–45, F.4, F.5.2, F.5.3, and H.9 (Art. 6.2) (see designation, name; see also effective publication).

LATIN TERMS AND THEIR ABBREVIATIONS USED IN THE MADRID CODE

This list includes Latin terms and their abbreviations, either or both of which appear in this Code, except for Latin words abbreviated as part of book or journal titles in bibliographic citations. Terms in bold have entries in the Glossary.