Nomenclatural codes

The ICN sets out principles, rules and recommendations for naming plants according to the binomial system employed by Linnaeus in his Species Plantarum (1753).  It makes provisions for naming taxa (a general word for all units of biological classification) at the levels of species, genus, family and above and, within species, for a number of infraspecific ranks, notably subspecies, varietas and forma. Names for hybrids between different taxa are also addressed. In addition to stipulations regarding the formation of names, the ICN also states the requirements of valid publication and presents a system for dealing with issues of priority and synonymy.  

Though some basic elements are deeply embedded in the ICN, other aspects are subject to amendment and adjustment according to changing ideas in taxonomy and developments in understanding and technology.  However, the ICN can only be revised at an International Botanical Conference (IBC).  The 19th IBC took place in Shenzhen, China in July 2017.

Many plants in gardens require no other name than that which would be attributed to them if they were found growing in the wild.  However, where plants which possess distinct, desirable characteristics, which can be maintained through a process of controlled propagation, are selected or bred, some additional means of identification and communication is required.  

Prior to the publication of the first edition of the ICNCP in 1953, the unregulated application of names to cultivated plants led to widespread confusion and a lack of clarity regarding the status implied by a name.

The ICNCP (sometimes called the Cultivated Plant Code) offers principles, rules and recommendations concerning the formation, establishment and styling of the names of cultivars, Groups and grexes. It also contains sections on registration and nomenclatural standard specimens.

Over the years the ICNCP has been altered and added to following International Symposia on the Taxonomy of Cultivated Plants. The latest version (the 9th edition) was published in 2016 following the Symposium in Beijing, China in July 2013.