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Timestamp: 2019-04-20 06:35:57+00:00

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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).
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 and 9.13). If the author used 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 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).
Note 2. For the purposes of this Code, the original material comprises: (a) those specimens and illustrations (both unpublished and published either prior to or together with the protologue) upon which it can be shown that the description or diagnosis validating the name was based; (b) the holotype and those specimens which, even if not seen by the author of the description or diagnosis validating the name, were indicated as types (syntypes or paratypes) of the name at its valid publication; and (c) the isotypes or isosyntypes of the name irrespective of whether such specimens were seen by either the author of the validating description or diagnosis, or the author of the name (but see also Art. 7.7, second sentence, and 7.8).
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).
Ex. 1. In the protologue of Laurentia frontidentata E. Wimm. (see Art. 37 Ex. 2) a single gathering in two herbaria was designated as the type. There must exist, therefore, at least two specimens and these are syntypes.
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. 2. The holotype of the name Rheedia kappleri Eyma (1932), which applies to a polygamous species, is a male specimen, Kappler 593a (U). The author designated a hermaphroditic specimen, Forestry Service of Surinam B. W. 1618 (U), as a paratype.
Note 3. 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.
Ex. 3. In the protologue of Eurya hebeclados Y. Ling (1951) the author simultaneously designated two specimens as types, Y. Ling 5014 as "typus, X" and Y. Y. Tung 315 as "typus, C", which are therefore syntypes. Ling also cited the specimen Y. Ling 5366 but without designating it as a type; it is therefore a paratype.
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).
Ex. 4. The holotype of Vitellaria paradoxa C. F. Gaertn. (1807) is a seed of unknown provenance (P), clearly belonging to the species currently known as Butyrospermum paradoxum (C. F. Gaertn.) Hepper. However, the two subspecies recognized within that species can only be distinguished by characters of foliage or inflorescence. Hall & Hindle (in Taxon 44: 410. 1995) designated an epitype with foliage, Mungo Park (BM). It belongs to the western subspecies, now to be known as B. paradoxum subsp. paradoxum.
Ex. 5. Podlech (in Taxon 46: 465. 1997) designated Herb. Linnaeus No. 926.43 (LINN) as the lectotype of Astragalus trimestris L. (1753). He simultaneously designated an epitype (Egypt. D�ben oberhalb Rosetta am linken Nilufer bei Schech Mantur, 9 May 1902, Anonymous (BM)), because the lectotype lacked fruits, "which show important diagnostic features for this species."
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).
Note 4. Correction can be effected only if the requirements of Art. 7.11 are met.
Ex. 6. 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 Note 2), 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).
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.
Ex. 7. The type of the name Tillandsia bryoides Griseb. ex Baker (1878) is Lorentz 128 (BM); this specimen, however, proved to be mixed. Smith (in Proc. Amer. Acad. Arts 70: 192. 1935) acted in accordance with Art. 9.12 in designating one part of Lorentz's specimen as the lectotype.
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.
Ex. 8. Erigeron plantagineus Greene (1898) was described from material collected by R. M. Austin in California. Cronquist (in Brittonia 6: 173. 1947) wrote "Type: Austin s.n., Modoc County, California (ND)", thereby designating the Austin material in ND as the [first-step] lectotype. Strother & Ferlatte (in Madro�o 35: 85. 1988), noting that there were two specimens of this gathering at ND, designated one of them (ND-G No. 057228) as the [second-step] lectotype. In subsequent references, both lectotypification steps may be cited in sequence.
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).
Note 5. An epitype supports only the type to which it is linked by the typifying author. If the supported type is superseded, the epitype has no standing with respect to the replacement type.
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 .

References: Art. 37
 Art. 9
 Art. 10
 Art. 9
 Art. 7
 Art. 9
 Art. 9
 Art. 7
 Art. 37
 Art. 37
 Art. 9
 Art. 59
 Art. 9
 Art. 7
 Art. 9
 Art. 9
 Art. 9
 Art. 38
 Art. 9
 Art. 9
 Art. 9
 Art. 9
 Art. 9
 Art. 9
 Art. 9
 Art. 57
 Art. 9
 Art. 9