In botanical nomenclature, a hybrid may be given a hybrid name, which is a special kind of botanical name, but there is no requirement that a hybrid name should be created for plants that are believed to be of hybrid origin. The International Code of Nomenclature for algae, fungi, and plants (ICNafp) provides the following options in dealing with a hybrid:
- A hybrid may get a name; this will usually be the option of choice for naturally occurring hybrids.
- A hybrid may also be indicated by a formula listing the parents. Such a formula uses the multiplication sign "×" to link the parents.
- Grex names can be given to orchid hybrids.
A hybrid name is treated like other botanical names, for most purposes, but differs in that:
- A hybrid name does not necessarily refer to a morphologically distinctive group, but applies to all progeny of the parents, no matter how much they vary.
- E.g., Magnolia × soulangeana applies to all progeny from the cross Magnolia denudata × Magnolia liliiflora, and from the crosses of all their progeny, as well as from crosses of any of the progeny back to the parents (backcrossing). This covers quite a range in flower colour.
- Grex names (for orchids only) differ in that they do not cover crosses from plants within the grex (F2 hybrids) or back-crosses (crosses between a grex member and its parent).
Hybrids can be named with ranks, like other organisms covered by the ICNafp. They are nothotaxa, from notho- (hybrid) + taxon. If the parents (or postulated parents) differ in rank, then the rank of the nothotaxon is the lowest. The names of nothospecies differ depending on whether they are derived from species within the same genus; if more than one parental genus is involved, then the nothospecies name includes a nothogenus name.
- Pyrus × bretschneideri is a hybrid between two species in the genus Pyrus.
- × Sorbopyrus auricularis in the nothogenus Sorbopyrus, is a hybrid between Sorbus aria and Pyrus communis.
Publication of names
Names of hybrids between genera (called nothogenera) can be published by specifying the names of the parent genera, but without a scientific description, and do not have a type. Nothotaxon names with the rank of a subdivision of a genus (notho-subgenus, notho-section, notho-series, etc.) are also published by listing the parent taxa and without descriptions or types.
Forms of hybrid names
A hybrid name can be indicated by:
- a multiplication sign "×" placed before the name of an intergeneric hybrid or before the epithet of a species hybrid. An intervening space is optional. e.g.:
- or by the prefix notho- attached to the rank,
The multiplication sign and the prefix notho- are not part of the actual name and are disregarded for nomenclatural purposes such as synonymy, homonymy, etc. This means that a taxonomist could decide to use either form of this name: Drosera ×anglica to emphasize that it is a hybrid, or Drosera anglica to emphasize that it is a species.
The names of intergeneric hybrids generally have a special form called a condensed formula, e.g., Agropogon for hybrids between Agrostis and Polypogon. Hybrids involving four or more genera are formed from the name of a person, with suffix -ara, e.g., ×Belleara. Names for hybrids between three genera can be either a condensed formula or formed from a person's name with suffix -ara.
- Botanical nomenclature
- Graft-chimaera names look similar, but use U+002B + PLUS SIGN.
- Glossary of scientific naming
- How to type the × symbol
- (McNeill et al. 2012, Article H.3, Note 1)
- (McNeill et al. 2012, Articles H.1 to H.12)
- Brickell, C.D.; Alexander, C.; David, J.C.; Hetterscheid, W.L.A.; Leslie, A.C.; Malecot, V.; Jin, X.; Cubey, J.J. (2009), International Code of Nomenclature for Cultivated Plants (ICNCP or Cultivated Plant Code) incorporating the Rules and Recommendations for naming plants in cultivation, Eighth Edition, Adopted by the International Union of Biological Sciences International Commission for the Nomenclature of Cultivated Plants (PDF), International Association for Plant Taxonomy and International Society for Horticultural Science
- (McNeill et al. 2012, Article H.5)
- (McNeill et al. 2012, Article H.9)
- (McNeill et al. 2012, Article H.6 and H.7)
- Stearn, William T. (May 1962). "The Origin of the Male and Female Symbols of Biology". Taxon. 11 (4): 111. doi:10.2307/1217734. JSTOR 1217734. S2CID 87030547.
Later, in his Mantissa Plantarum (1767) and Mantissa Plantarum altera (1771), Linnaeus regularly used ♂, ♀ and ☿ for male, female and hermaphrodite flowers respectively. Their aptness made them easy to remember and their convenience led to their general acceptance in zoology as well as botany. Koelreuter found them especially convenient when recording his experiments in hybridization; as late as 1778 he used the sign to denote a hybrid plant. No evidence of the use of these signs for this purpose before Linnaeus's time has been found.
- McNeill, J.; et al. (Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G.F.; Wiersema, J.H.; Turland, N.J.) (2012). International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011. Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN 978-3-87429-425-6.