Concept
A Group (previously cultivar-group) is a formal category in the International Code of Nomenclature for Cultivated Plants (ICNCP) used for cultivated plants (cultivars) that share a defined characteristic. It is represented in a botanical name by the symbol Group or Gp. "Group" or "Gp" is always written with a capital G in a botanical name, or epithet. The Group is not italicized in a plant's name. The ICNCP introduced the term and symbol "Group" in 2004, as a replacement for the lengthy and hyphenated "cultivar-group", which had previously been the category's name since 1969. For the old name "cultivar-group", the non-standard abbreviation cv. group or cv. Group is also sometimes encountered. There is a slight difference in meaning, since a cultivar-group was defined to comprise cultivars, whereas a Group may include individual plants. The ICNCP distinguishes between the terms "group" and "Group", a "group" being "an informal taxon not recognized in the ICBN", while a "Group" is the formal taxon defined by the ICNCP (see above). This categorization does not apply to plant taxonomy generally, only to horticultural and agricultural contexts. Any given Group may have a different taxonomic classification, such as a subspecific name (typically a form or variety name, given in italics) after the genus and species. A Group is usually united by a distinct common trait, and often includes members of more than one species within a genus. For example, early flowering cultivars in the genus Iris form the Iris Dutch Group. A plant species that loses its taxonomic status in botany, but still has agricultural or horticultural value, meets the criteria for a cultivar group, and its former botanical name can be reused as the name of its cultivar group. For example, Hosta fortunei is usually no longer recognized as a species, and the ICNCP states that the epithet fortunei can be used to form Hosta Fortunei Group.