A Danish plant name can mean two different plants, but the botanical name is the same all over the world. Here are the international rules for writing genus, species, hybrids, cultivars and trade designations — and why names can change.
Introduction
A Danish name can mean two different plants, and the same plant can have several Danish names. The botanical name is the same all over the world. When you order plants, read a drawing or check a delivery note, you must be able to read and write the name correctly. The programme also requires it: you must be able to «apply international rules for classification and naming».
Two sets of rules
- 01ICN (International Code of Nomenclature for algae, fungi, and plants) governs genus, species and hybrids. The current edition is the Madrid Code of 2025, which replaced the Shenzhen Code of 2018.
- 02ICNCP (the code for cultivated plants), 9th edition from June 2016, governs cultivars, groups and trade designations.
Genus and species
A species name has two parts: the genus name followed by one species epithet (ICN Art. 23.1). The genus is written with a capital initial, and the species epithet with a lower-case initial (Rec. 60F.1). Both parts are written in italics. Example: Acer platanoides (Norway maple).
Hybrids
A hybrid is a cross. It is marked with the multiplication sign ×. In a hybrid between species the × goes before the species epithet, and in a hybrid between genera the × goes before the genus name (ICN Art. H.3.1). Example: Tilia × europaea (common lime). Write the sign ×, not the letter x.
Cultivars
- 01The cultivar name is in single quotation marks. «cv.», «var.» and double quotation marks must not be used for a cultivar (ICNCP Art. 14.1). Example: Acer platanoides 'Globosum'.
- 02The cultivar name is not written in italics when the genus and species are in italics (Rec. 8A.1).
- 03Each word in the cultivar name starts with a capital letter (Art. 21.3).
- 04New cultivar names from 1 January 1959 must not be entirely in Latin (Art. 21.11), and from 1 January 1996 they may have at most 30 characters (Art. 21.13).
- 05On labels from before 1996 you may still see «cv.» before the cultivar (Art. 14, note 2).
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