Basionym

Basionym (with its roots in Greek elements meaning 'base' and 'name') is a term used in botany, regulated by the International Code of Botanical Nomenclature. It applies, for instance, when the binomial name of a species is changed (for taxonomic or nomenclatural reasons) and the new name is based on an earlier name, the basionym.

The basionym of the name Picea abies (the Norway Spruce), for example, is Pinus abies. The species was originally named Pinus abies by Carolus Linnaeus; later botanist Karsten decided it should not be in the same genus Pinus as the pines, but in a separate genus: he transferred it to the genus Picea (the spruces).

The term basionym is defined by the International Code of Botanical Nomenclature:

"basionym. A previously published legitimate name-bringing or epithet-bringing synonym from which a new name is formed for a taxon of different rank or position (Art. 33.4, 49.1 and 52.3)"

Notes

• Where a name contains an epithet, the ending of this epithet follows the gender of the generic name; this may mean a change from the spelling in the basionym. For example Acrocarpia paniculata, the basionym of which is Fucus paniculatus.

• Note an example of transfer from epithet to genus name where the basionym Cactus opuntia (L.) 1754 was renamed by Miller Opuntia ficus-indica (L.) Mill. 1768.

• Where a so-called nomen novum is created, the term basionym does not apply.

• Bacteriology uses a similar term, basonym, spelled without an i.
• The term is sometimes used in zoology.