Botanical nomenclature is the formal naming of plants, from a scientific point of view. It has a long history, going back perhaps to Theophrastos, but anyway back to the period when Latin was the scientific language throughout Europe. The keystone event was Linnaeus’ adoption of binary names for plant species in his Species Plantarum (1753). This gave every plant species a name which remained the same no matter what other species were placed in the genus, and thus separated taxonomy from nomenclature. These species names of Linnaeus together with names for other ranks, notably the rank of family (not used by Linnaeus), can serve to express a great many taxonomic viewpoints.
In the nineteenth century it became increasingly clear that there was a need for rules to govern scientific nomenclature and initiatives were taken to come to a body of laws. These were published in successively more sophisticated editions. For plants the key dates are 1867 (lois de Candolle), 1906 (International Rules of Botanical Nomenclature, 'Vienna Rules') and 1952 (International Code of Botanical Nomenclature, 'Stockholm Code').
Another development was insight into delimitation of the concept 'plant'. Linnaeus held a much wider view of what a plant is than is acceptable today. Gradually more and more groups of organisms are recognised as being independent of plants. Nevertheless the formal names of most of these organisms are governed by the International Code of Botanical Nomenclature (ICBN), even today. A separate Code was adopted to govern the nomenclature of Bacteria, the ICNB.
At the moment all formal botanical names are governed by the ICBN. Within the limits set by the ICBN there is a separate set of rules, the International Code of Nomenclature for Cultivated Plants (ICNCP). Within the group of plants that have been deliberately altered or selected by humans (see cultigen) there are those that require separate recognition, known as cultivars. Within the limits set by the ICNCP there is a separate set of rules for orchid hybrids.
Relationship to taxonomy
Botanical nomenclature is closely linked to plant taxonomy, and botanical nomenclature serves plant taxonomy, but nevertheless botanical nomenclature is separate from plant taxonomy. Botanical nomenclature is merely the body of rules prescribing which name applies to that taxon (see correct name) and if a new name may (or must) be coined.
Plant taxonomy is an empirical science, a science that determines what constitutes a particular taxon (taxonomic grouping, plural: taxa): e.g. "What plants belong to this species?" and "What species belong to this genus?"). Where taxonomists differ in opinion more than one name may be used for one and the same plant. Within any taxonomic viewpoint only one name can be correct, but somebody holding a different taxonomic viewpoint may be using a different name, although for him too there is only one correct name (in his taxonomic viewpoint).
This means that in case of confusion:
⇒ If confusion is nomenclatural (for example an older name is discovered which has priority and threatens to displace a well-known name), the Code offers means to set things right (at least sometimes): see conservation.
⇒ If confusion is taxonomic (taxonomists differ in opinion on the circumscription or the relationships of taxa), then only more scientific research can settle this.
⇒ Botanical name
⇒ Nomenclature Codes
⇒ International Code of Botanical Nomenclature
⇒ International Code of Nomenclature for Cultivated Plants