Nomenclatural type specimens are important elements of botanical nomenclature. The name of a taxon is permanently attached to the type, whether as a correct name or as a synonym. These valuable specimens should be given extra care and protection.
The rules and practice of typification have changed over the years. The current rules and recommendations are detailed in the The International Code of Botanical Nomenclature, ICBN, (Division II, Section 2, Typification, Articles 7, 8, 9, 10). Prior to 1 January 1958 the publication of the new name of a taxon of the rank of genus or below did not require the designation of a type in the publication. References to type specimens in early plant systematics literature are absent or vague. Older specimens often lack complete collection data. Getting these types, specimens and nomenclature sorted out often requires the expertise of a specialist in the plant group and pertinent literature. The specialist is the ideal person to address these problems and provide definitive resolution.
Type specimen annotations require more detail than most other annotations. General information on annotating herbarium specimens may be found in: Annotation of Herbarium Specimens: Recommendations. The following guidelines may be helpful.
- Each type should be annotated with the following:
- The kind of type (see list of type definitions below)
- The basionym (first valid scientific name applied to a taxon, i.e., the name on which combinations, if any, are based)
- The complete literature citation
- The determiner and date
- Optionally, the institution of the determiner, the project name and relevant comments. E.g., “Isotypes at B, FLAS, M and NY.”
- If the currently accepted name differs from the basionym, the specimen should also be annotated with the currently accepted name.
The basionym and the currently accepted name are the same:
The basionym and the currently accepted name are different:
Currently accepted name annotation:
Combined information on one annotation:
Lectotype annotation, taxon currently treated under transferred name:
Type Definitions (based on ICBN, Chapter II, Section 2, Article 9)
- Holotype: the one specimen or illustration used by the author, or designated by the author as the nomenclatural type.
- Isotype: any duplicate specimen of the holotype.
- Lectotype: a specimen or illustration designated as the type when no holotype was indicated at the time of publication. If possible, the lectotype should be selected from the syntypes or original material. (Also, see “isolectotype” in list below.)
- Syntype: 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 in the original description. Monographers are urged to select a lectotype from among the syntypes whenever possible.
- Isosyntype: a duplicate specimen of a syntype.
- Neotype: a specimen or illustration selected as the type when all of the material on which the name of the taxon was based is missing. (Also, see “isoneotype” in list below.)
- Paratype: a specimen cited in the protologue that is neither the holotype, isotype, nor one of the syntypes. These are often listed as representative specimens in the original description.
- Epitype: “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.” (ICBN Ch. 2, Sec. 2, Art. 9.7) The holotype, lectotype, or neotype that the epitype supports must be explicitly cited when the epitype is designated (see Art. 9.18).
* The terms specimen and duplicate are given their usual meaning in herbarium curatorial practice. A specimen and its duplicates are part of a single gathering of a single species or infraspecific taxon made by a collector at one time. Although not specifically stated in ICBN, the specimen and its duplicates should all have the same collector number.
Other Type Terms (these terms are commonly used but are not officially designated in the ICBN)
- Isolectotype: any duplicate specimen of the lectotype.
- Isoneotype: any duplicate specimen of the neotype.
- Non-types: specimens which are erroneously labelled as types should be annotated as, “Not a Type.”
- Topotype: a specimen of the same species as the type collected from the original type locality.