9.1. A holotype of a name of a species or infraspecific taxon is the one specimen or illustration 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 (see also Art. 10).
Note 1. Any designation made by the original author, if definitely expressed at the time of the original publication of the name of the taxon, is final (but see Art. 9.9). If the author included only one element, that one must be accepted as the holotype. If a new name is based on a previously published description or diagnosis of the taxon, the same considerations apply to material included by the earlier author (see Art. 7.7 and 7.8).
9.2. A lectotype is a specimen or illustration (see Art. 8.3) designated as the nomenclatural type, in conformity with Art. 9.9, when no holotype was indicated at the time of publication, when the holotype is found to belong to more than one taxon, or as long as it is missing.
9.3. An isotype is any duplicate1 of the holotype; it is always a specimen.
9.4. A syntype is any one of two or more specimens cited in the protologue when no holotype was designated, or any one of two or more specimens simultaneously designated as types.
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.
Ex. 1. The holotype of the name Rheedia kappleri Eyma, which applies to a polygamous species, is a male specimen collected by Kappler (593a in U). The author designated a hermaphroditic specimen collected by the Forestry Service of Surinam as a paratype (B. W. 1618 in U).
Note 2. In most cases in which no holotype was designated there will also be no paratypes, since all the cited specimens will be syntypes. However, when an author designated two or more specimens as types (Art. 9.4), any remaining cited specimens are paratypes and not syntypes.
9.6. A neotype is a specimen or illustration (see Art. 8.3) selected to serve as nomenclatural type as long as all of the material on which the name of the taxon was based is missing (see also Art. 9.11).
9.7. An epitype is a specimen or illustration selected to serve as an interpret-ative 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. When an epitype is designated, the holotype, lectotype or neotype that the epitype supports must be explicitly cited.
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).
Ex. 2. Borssum Waalkes (in Blumea 14: 198. 1966) cited Herb. Linnaeus No. 866.7 (LINN) as the holotype of Sida retusa L. (1763). The term is incorrectly used because illustrations in Plukenet (Phytographia: t. 9, f. 2. 1691) and Rumphius (Herb. Amboin. 6: t. 19. 1750) were cited by Linnaeus in the protologue of S. retusa. Since all three elements are original material (Art. 9.9, footnote), Borssum Waalkes's use of holotype is an error to be corrected to lectotype.
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). A lectotype always takes precedence over a neotype, except as provided by Art. 9.11. An isotype, if such exists, must be chosen as the lectotype. If no isotype exists, the lectotype must be chosen from among the syntypes, if such exist. If neither an isotype nor a syntype nor an isosyntype (duplicate of syntype) nor any other part of the original material is extant, a neotype may be selected.
Note 3. When two or more specimens have been designated as types by the author of a name (e.g. male and female, flowering and fruiting, etc.), the lectotype must be chosen from among them (see Art. 9.4).
9.10. 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.
Ex. 3. The type of the name Tillandsia bryoides Griseb. ex Baker (1878) is Lorentz 128 in BM; this, however, proved to be a mixture. Smith (in Proc. Amer. Acad. Arts 70: 192. 1935) acted in accordance with this rule in designating one part of Lorentz's gathering as the lectotype.
9.11. 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. 9.12).
9.12. A neotype selected under Art. 9.11 may be superseded if it can be shown to differ taxonomically from the holotype or lectotype that it replaced.
9.13. The author who first designates a lectotype or a neotype must be followed, but his choice is superseded if (a) the holotype or, in the case of a neotype, any of the original material is rediscovered; it may also be superseded if (b) it can be shown that it is in serious conflict with the protologue and another element is available which is not in conflict with the protologue, or (c) that it is contrary to Art. 9.10.
9.14. On or after 1 January 1990, lectotypification or
neotypification of a name of a species or infraspecific taxon
by a specimen or unpublished illustration (see Art. 8.3)
is not effected unless the herbarium or institution in which the
type is conserved is specified.
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 species or specimen 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 collection is cited in the protologue, but a particular institution housing this 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 he used further material of the same collection.
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, the residue or part of it should be designated as the lectotype provided that this element is not in conflict with the original description or diagnosis (see Art. 9.13).
9A.6. For the name of a fossil species, the lectotype,
when one is needed, should, if possible, be a specimen illustrated
at the time of the valid publication of the name (see Art. 8.4).
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,
and if this selection proves to be faulty, it will inevitably
result in further change.