A type specimen is a specimen selected to serve as a reference point when a plant species is first named. As a result, these specimens are extremely important to botanists who are attempting to determine the correct application of a name. They are often specially curated in herbaria, such as at the NYBG, where they are filed separately. There are several different categories of types; the most common are:

Holotype: The single specimen designated as the type of a species by the original author at the time the species name and description was published.

Isotype: A duplicate specimen of the holotype.

Syntype: Any of two or more specimens listed in the original description of a taxon when a holotype was not designated.

Isosyntype: A duplicate of a syntype.

Paratype: A specimen not formally designated as a type but cited along with the type collection in the original description of a taxon.

Lectotype: A specimen chosen by a later researcher to serve as if it were the holotype. It is chosen from among the specimens available to the original publishing author (the isotypes, syntypes and/or paratypes) of a scientific name when the holotype was either lost or destroyed, or when no holotype was designated.

Neotype: A specimen chosen by a later researcher to serve in place of a holotype when all specimens available to the original publishing author of a scientific name have been lost or destroyed.

Topotype: A specimen of a plant collected from the same locality as the holotype and usually on a different date. A topotype has no formal standing. = locotype

Cotype: A term formerly used for syntype and sometimes (erroneously) for isotype and paratype. This is an old term that was used loosely and is not used by today's taxonomists.

Generitype: The type specimen of a genus. It is designated by using the type for the name of a particular species within that genus. For example, the generitype for Aster is the type for Aster amellus L.