Explanation of terms
Accepted name:the correct name for any taxon, in accordance with the rules in the Codes of Nomenclature.
Article:a collection of associated rules and recommendations in a Code of Nomenclature; rules are binding.
Author:the person to whom a name or publication is attributed.The authors of plant names are sometimes referred to as “authorities”.
Author abbreviation:an abbreviated author’s name used in an author citation, e.g. L. for Linnaeus.
Backcross:a cross between a hybrid and one of its parents.
Basionym:the original name in which an epithet was first published. The species epithet non-scripta was first applied to the English bluebell as Scilla non-scripta, which remains the basionym even though the species is now called Hyacinthoides non-scriptus.
Binomial:the scientific name of a species, consisting of two words. The first word is the name of the genus and the second is the epithet given to that species to distinguish it from others in the genus. In the binomial (species name) Rosa canina, Rosa is the genus name and canina is the species epithet.
Clone:a number of genetically identical individuals resulting from asexual reproduction.
Code:one of the International Codes of Nomenclature.
Common (vernacular) name:the non-scientific name of a taxon in a modern language.
Conserved:a name contrary to the rules in either Code may be conserved if adopted as correct by ruling of the body responsible for such decisions.
Conspecific:describes plants belonging to the same species.
Convar (convarietas):an informal category for cultivated plants sometimes placed among the ranks of the taxonomic hierarchy. It is not recognised by either of the Codes of Nomenclature.
Cultigen:a taxon believed to have originated in cultivation.
Cultivar:a taxon of cultivated plants that is clearly distinct, uniform and stable in its characters and which, when propagated by appropriate means, retains those characters.
Cultivar epithet:the final element of a full cultivar name, enclosed in single quotation marks to distinguish it from the scientific name that precedes it.
Denomination class:a genus, species, Group or other taxon within which identical or similar cultivar names should not be used.
Diaeresis:a diacritical sign (¨) placed over the second of two consecutive vowels to indicate that they are to be pronounced separately.
Diagnosis:a short statement, usually in Latin, which specifically describes how a new taxon differs from similar, previously described taxa. Can stand in place of a full Latin description for a new taxon.
Effective publication:(for names governed by the Botanical Code) publication in a printed, widely distributed, publicly available book or journal. Names governed by the Cultivated Plant Code are described as “published” if they appear in books, journals or trade catalogues.
Epithet:the final element of a species, Group or cultivar name when considered alone. In the species name Malva moschata, the specific epithet is moschata; in the Group name Solanum tuberosum Maincrop Group, the Group epithet is Maincrop Group; in the cultivar name Malva moschata ‘Pink Perfection’, the cultivar epithet is ‘Pink Perfection’.
Establishment:publication of a Group or cultivar name which is in accordance with the rules of the Cultivated Plant Code.
F1 hybrid:the first generation resulting from crossing different plants or taxa; used more strictly in plant breeding for the result of a repeatable single cross between two pure-bred lines.
F2 hybrid:a plant-breeding term for the result of self-pollination within an F1 population.
Family:the main rank into which related genera are grouped.
Forma (f., plural formae):the rank below varietas (variety) in the taxonomic hierarchy, often informally referred to as “form”.
Genus (plural genera):the main rank between family and species in the taxonomic hierarchy.
Graft-chimaera:a plant consisting of tissue from two or more species in intimate association resulting very infrequently from grafting.
Grex (gx, plural greges or informally grexes):a special type of Group, now used exclusively in orchid nomenclature, applied to the progeny of an artificial cross between known parents.
Group:a category governed by the Cultivated Plant Code encompassing plants (usually named cultivars) which share certain defined characters. A Group does not have to contain, or be solely composed of, cultivars.
Homonym:when two or more taxa have been given the same scientific name, these names are described as homonyms. The first name published will normally have priority.
Hybrid:the result of crossing different plants or taxa.
Hybrid formula:the names of the parents of a hybrid linked by a multiplication sign, e.g. Solanum nigrum × S. physalifolium.
International Cultivar Registration Authority (ICRA):an organisation or individual responsible for registering Cultivar and Group names for a particular taxon, usually a family, genus, species or other denomination class. There are for example ICRAs for conifers, Orchidaceae, Narcissus, Rhododendron and Prunus mume, among many others.
Legitimate name:a name published in accordance with the rules set out in the Botanical Code.
Line:a plant-breeding term used to describe plants resulting from self-fertilisation, inbreeding or repeated selection.
Nomenclatural standard:a herbarium specimen, seed sample, illustration or other reference material to which the name of a cultivar or Group is permanently attached. Such material should be maintained to demonstrate the diagnostic characters of the cultivar in question.
Nomenclatural type:under the Botanical Code a specimen on which the formal description of a taxon is based. This is usually a herbarium specimen and serves as the defining reference point for the correct application of the name in question.
Plant Breeders’ Rights (PBR):a form of intellectual property (IP) rights granted to the breeder of a new cultivar for a certain period, if the cultivar meets certain clearly defined criteria.
Plant Patent:a form of intellectual property (IP) rights similar to Plant Breeders’ Rights.
Plant Variety Rights (PVR):a form of intellectual property (IP) rights similar to Plant Breeders’ Rights.
Priority:an important principle of nomenclature whereby the earliest valid publication of a name takes priority over later names.
Rank:one of the hierarchical categories used in plant classification.
Registration:the act of registering a Cultivar or Group name by the appropriate International Cultivar Registration Authority.
Selling name:see Trade designation.
Sensu lato (s.l.):in the broad sense.
Sensu stricto (s.s.):in the narrow sense.
Series:a collective category used as a marketing device, which usually (though by no means always) links morphologically similar plants differing in a single character such as flower or leaf colour. Being strictly commercial and often given trademarks, they are not governed by either Code of Nomenclature. Not to be confused with the botanical rank “series”, an optional subdivision of genus.
Species (sp.; plural species, spp.):the main rank below genus in the taxonomic hierarchy.
Species epithet:the second part of a binomial, the first part being the genus.
Standard Portfolio:the nomenclatural standard together with any additional material such as extra herbarium specimens or illustrations, descriptions, details of registration and parentage, nursery catalogues, and DNA data or samples.
Subspecies (subsp.):the main rank below species in the taxonomic hierarchy.
Synonym:a valid name for a taxon that is not currently accepted, usually through application of the Principle of Priority.
Taxon (plural taxa):a taxonomic group at any rank, e.g.genus, species, subspecies, variety, Group or cultivar.
Trade designation:a name used to market a plant when the original cultivar epithet is considered unsuitable for selling purposes; not recognised by either of the Codes of Nomenclature. Also known as a selling name.
Trademark:a sign, usually made from words, letters, numbers or symbols, that identifies the goods of a particular enterprise, distinguishing them from the goods of its competitors.
Trinomial:a binomial followed by a third epithet with no indication of its rank.
Type specimen:see Nomenclatural type.
UPOV (Union Internationale pour la Protection des Obtentions Vegetales):the International Union for the Protection of New Varieties of Plants is an intergovernmental organisation whose objective is the protection of new varieties (cultivars) of plants by intellectual property rights.
Valid name:a name published in accordance with the rules set out in the Codes of Nomenclature.
Variant:an informal term for a plant or group of plants which shows some character differences from others in the same taxon.
Varietas (var.):the main rank between species and forma in the taxonomic hierarchy.
Variety:an informal term for varietas (q.v.) but sometimes also used instead of cultivar. The distinction between varietas and cultivar is an important one.
Variety denomination:a cultivar epithet designated by a statutory authority.