In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the tiger cowry of the Indo-Pacific, Cypraea (Cypraea) tigris Linnaeus, which belongs to the subgenus Cypraea of the genus Cypraea. However, it is not mandatory, or even customary, when giving the name of a species, to include the subgeneric name.
In the International Code of Nomenclature for algae, fungi, and plants, the subgenus is one of the possible subdivisions of a genus. There is no limit to the number of divisions that are permitted within a genus by adding the prefix "sub-" or in other ways as long as no confusion can result. The secondary ranks of section and series are subordinate to subgenus.