Type specimen  

A type specimen is a herbarium specimen and it is the material representing the species name
Therefore the type specimen (holotype, isotype, neotype, lectotype) is paramount and should be used in all taxonomic studies and resulting classifications
The problem of this basic concept is that in modern-day molecular studies, it is usually not possible to obtain sequences from the types and therefore we must use fresh collections
This creates the problem that sequence data may come from incorrectly named isolates which can make the whole taxonomic study questionable


The one specimen or illustration used by the author or designated by the author as the nomenclatural type


Any duplicate specimen of the holotype


A specimen or illustration selected as the type when all of the material on which the name of the taxon was based is missing


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


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
Monographers are urged to select a lectotype from among the syntypes whenever possible


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