|INTERNATIONAL CODE OF BOTANICAL NOMENCLATURE online
9.1. A holotype of a name of a species or infraspecific taxon is the one specimen or illustration (but see Art. 37.4) used by the author, or designated by the author as the nomenclatural type. As long as a holotype is extant, it fixes the application of the name concerned (but see Art. 9.13; see also Art. 10).
9.2. A lectotype is a specimen or illustration designated from the original material as the nomenclatural type, in conformity with Art. 9.9 and 9.10, if no holotype was indicated at the time of publication, or if it is missing, or if it is found to belong to more than one taxon (see also Art. 9.12).
9.3. An isotype is any duplicate of the holotype; it is always a specimen.
9.4. A syntype is any specimen cited in the protologue when there is no holotype, or any one of two or more specimens simultaneously designated as types (see also Art. 37 Note 1).
9.5. A paratype is a specimen cited in the protologue that is neither the holotype nor an isotype, nor one of the syntypes if two or more specimens were simultaneously designated as types.
9.6. A neotype is a specimen or illustration selected to serve as nomenclatural type if no original material is extant, or as long as it is missing (see also Art. 9.14).
9.7. An epitype is a specimen or illustration selected to serve as an interpretative type when the holotype, lectotype, or previously designated neotype, or all original material associated with a validly published name, is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name of a taxon (but see also Art. 59.7). When an epitype is designated, the holotype, lectotype, or neotype that the epitype supports must be explicitly cited (see Art. 9.18).
9.8. The use of a term defined in the Code (Art. 9.1-9.7) as denoting a type, in a sense other than that in which it is so defined, is treated as an error to be corrected (for example, the use of the term lectotype to denote what is in fact a neotype).
9.9. If no holotype was indicated by the author of a name of a species or infraspecific taxon, or when the holotype has been lost or destroyed, or when the material designated as type is found to belong to more than one taxon, a lectotype or, if permissible (Art. 9.6), a neotype as a substitute for it may be designated (Art. 7.10 and 7.11).
9.10. In lectotype designation, an isotype must be chosen if such exists, or otherwise a syntype if such exists. If no isotype, syntype or isosyntype (duplicate of syntype) is extant, the lectotype must be chosen from among the paratypes if such exist. If no cited specimens exist, the lectotype must be chosen from among the uncited specimens and cited and uncited illustrations which comprise the remaining original material, if such exist.
9.11. If no original material is extant or as long as it is missing, a neotype may be selected. A lectotype always takes precedence over a neotype, except as provided by Art. 9.14.
9.12. When a type specimen (herbarium sheet or equivalent preparation) contains parts belonging to more than one taxon (see Art. 9.9), the name must remain attached to that part which corresponds most nearly with the original description or diagnosis.
9.13. The holotype (or lectotype) of a name of a species or infraspecific taxon of fossil plants (Art. 8.5) is the specimen (or one of the specimens) on which the validating illustrations (Art. 38) are based. When, prior to 1 January 2001 (see Art. 38.2), in the protologue of a name of a new taxon of fossil plants of the rank of species or below, a type specimen is indicated (Art. 37.1) but not identified among the validating illustrations, a lectotype must be designated from among the specimens illustrated in the protologue. This choice is superseded if it can be demonstrated that the original type specimen corresponds to another validating illustration.
9.14. When a holotype or a previously designated lectotype has been lost or destroyed and it can be shown that all the other original material differs taxonomically from the destroyed type, a neotype may be selected to preserve the usage established by the previous typification (see also Art. 9.16).
9.15. A designation of a lectotype or neotype that later is found to refer to a single gathering but to more than one specimen must nevertheless be accepted (subject to Art. 9.17), but may be further narrowed to a single one of these specimens by way of a subsequent lectotypification or neotypification.
9.16. A neotype selected under Art. 9.14 may be superseded if it can be shown to differ taxonomically from the holotype or lectotype that it replaced.
9.17. The author who first designates a lectotype or a neotype must be followed, but that choice is superseded if (a) the holotype or, in the case of a neotype, any of the original material is rediscovered; the choice may also be superseded if one can show that (b) it is in serious conflict with the protologue and another element is available that is not in conflict with the protologue, or that (c) it is contrary to Art. 9.12.
9.18. The author who first designates an epitype must be followed; a different epitype may be designated only if the original epitype is lost or destroyed. A lectotype or neotype supported by an epitype may be superseded in accordance with Art. 9.17 or, in the case of a neotype, Art. 9.16. If it can be shown that an epitype and the type it supports differ taxonomically and that neither Art. 9.16 nor 9.17 applies, the name may be proposed for conservation with a conserved type (Art. 14.9; see also Art. 57).
9.19. Designation of an epitype is not effected unless the herbarium or institution in which the epitype is conserved is specified or, if the epitype is a published illustration, a full and direct bibliographic reference to it is provided.
9.20. On or after 1 January 1990, lectotypification or neotypification of a name of a species or infraspecific taxon by a specimen or unpublished illustration is not effected unless the herbarium or institution in which the type is conserved is specified.
9.21. On or after 1 January 2001, lectotypification or neotypification of a name of a species or infraspecific taxon is not effected unless indicated by use of the term "lectotypus" or "neotypus", its abbreviation, or its equivalent in a modern language (but see Art. 9.8).
9A.1. Typification of names for which no holotype was designated should only be carried out with an understanding of the author's method of working; in particular it should be realized that some of the material used by the author in describing the taxon may not be in the author's own herbarium or may not even have survived, and conversely, that not all the material surviving in the author's herbarium was necessarily used in describing the taxon.
9A.2. Designation of a lectotype should be undertaken only in the light of an understanding of the group concerned. In choosing a lectotype, all aspects of the protologue should be considered as a basic guide. Mechanical methods, such as the automatic selection of the first element cited or of a specimen collected by the person after whom a species is named, should be avoided as unscientific and productive of possible future confusion and further changes.
9A.3. In choosing a lectotype, any indication of intent by the author of a name should be given preference unless such indication is contrary to the protologue. Such indications are manuscript notes, annotations on herbarium sheets, recognizable figures, and epithets such as typicus, genuinus, etc.
9A.4. When a single gathering is cited in the protologue, but a particular institution housing it is not designated, it should be assumed that the specimen housed in the institution where the author is known to have worked is the holotype, unless there is evidence that further material of the same gathering was used.
9A.5. When two or more
heterogeneous elements were included in or cited with the original
description or diagnosis, the lectotype should be so selected as to
preserve current usage. In particular, if another author has already
segregated one or more elements as other taxa, one of the remaining elements
should be designated as the lectotype provided that this element is
not in conflict with the original description or diagnosis (see Art. 9.17).
9B.1. In selecting a neotype, particular care and critical knowledge should be exercised because the reviewer usually has no guide except personal judgement as to what best fits the protologue; if this selection proves to be faulty it will inevitably result in further change.
(c) 2006, by International Association for Plant Taxonomy. This page last updated 11.03.2007 .