INTERNATIONAL CODE OF BOTANICAL NOMENCLATURE (ICBN)

            A. HISTORY

            Carolus Linnaeus proposed the elementary rules of naming plants first in his book ‘Critica Botanica’ (1737) and then in ‘Philosophia Botanica’ (1751). Later A.P. de. Candolle (1813), set forth a detailed set of rules regarding the nomenclature of plants in his book ‘Theorie Elementaire de la Botanique’. The same rules of Linnaeus, A.P. de. Candolle and his son Alphonse de Candolle were later evolved into our present International code of Botanical Nomenclature (ICBN).

            The first ‘International Botanical Congress (IBC), was held in Paris in 1867 where Alphonse de Candolle was the president. Botanists from several countries were attended there. They adopted a set of rules of plant nomenclature, most of which were proposed by Alphonse de candolle. The excellent rules of plant nomenclature are known as ‘de Candolle rules or Paris Code of 1967’.

            The names of all the codes along with the years are – 1. Paris Code (1867), 2. Rochester Code (1892), 3. Vienna Code (1905), 4. American Code (1907), 5. Brussels Code (1912), 6. Cambridge Code (1930), 7. Amsterdam Code (1947), 8. Stockholm Code (1966), 9. Paris Code (1956), 10. Montreal Code (1961), 11. Edinburgh Code (1966), 12. Seattle Code (1972), 13. Leningard Code (1978), 14. Sydney Code (1983), 15. Berlin Code (1988), 16. Tokyo Code (1994), 17. St Louis Code (1999), 18. Vienna Code (2005), 19. Melbourne Code (2011). According to the resolutions of the IBC 2011, the 19^th IBC is to be held in Shenzhen, Guangdong province, China on July 23–29/2017.

            The general agreement regarding the internationally acceptable rules of plant nomenclature was reached in the meeting of the IBC at Cambridge in 1930 where for the first time in botanical history a code of nomenclature came into being that was international in function as well as in name. This code is called the International Code of Botanical Nomenclature.

            The ICBN is divided into Principles, Rules and Recommendations. The present code consists of 6 principles, about 75 rules set out in the Article, 57 recommendations and a number of notes and examples. It also includes Appendices I, II and III and a guide for the determination of types and citations of botanical literature. Appendix I gives rules regarding names of hybrids and some special categories. Appendix II gives the list of conserved names of families and Appendix III gives the list of conserved and rejected generic names.

            B. PRINCIPLES OF ICBN

            The philosophical basis of the code is formed by the following six principles –

            1. Botanical nomenclature is independent of zoological nomenclature.

            2. The application of names of taxonomic groups is determined by means of nomenclatural types.

            3. The nomenclature of a taxonomic group is based upon ‘priority of publication’.

            4. Each taxonomic group with a particular circumscription, position and rank can bear only one correct name, the earliest that is in accordance with the rules, except in specific cases.

            5. Scientific names of groups are treated as Latin regardless of their derivation.

            6. The rules of recommendation are retroactive unless expressly limited.

            C. RULES OF ICBN

Some of the more important rules/aspects of ICBN are discussed below –

1. Principle of Priority of Publication:

Principle II of ICBN states that the nomenclature of a taxonomic group is based on priority of publication. One plant might have been described under different botanical names by various plant nomenclaturists in different parts of the world. But according to the ‘Principle of Priority’ each taxon is known by its earliest name, however the same species was named differently in different parts of the world. For example – Indian Coral tree (Erythrina variegate L.) has as many as 200 scientific names.

Limitations of Priority of Publication:- The rule of priority has certain limitations. It cannot be applied to all names published. Valid publication of names of different groups of plants is treated as beginning on various dates as provided in the code (Article 13). In case of Spermatophytes and Pteridophytes, it is 1^st May 1753, the date of publication of Linnaeus ‘Species Plantarum’. Names published before this date need not be considered in applying, the rule of priority.

2. Typication/ Type Method/ Nomenclatural Type:

 Type method is one of the important principles of the Code. The Type Method is a legal device to provide the correct name of the taxon. A ‘type specimen’ is a herbarium sheet (or rarely a drawing or a photograph) of a specimen which was used by the author to provide its authentic description. Article 7 of the Code states that, the application of the names of taxa of the rank of family or below is determined by means of ‘nomenclatural types’. According to Article 9 of ICBN, the type of a genus is a species (e,g., the type species of the genus Brassica is B. compestris or B. compestris is the type species of the genus Brassica. Similarly, the type of the family is a genus (e.g., Brassica is the type genus of the family Brassicaceae).

Kinds of ‘Type’:- The different kinds of ‘type’ designated by ICBN are as follows –

(a) Holotype – It is a specimen used by the author in the original publication as the nomenclatural type.

(b) Isotype – It is a duplicate specimen of the holotype, i.e., from the same collection with the same locality, date and number as the holotype.

(c) Lectotype – It is a specimen selected from the original material, when no holotype was designated at the time of publication or as long as it is missing or destroyed.

(d) Neotype – It is a specimen selected to serve as a substitute of holotype when all the material on which the name of the taxon was based is missing.

(e) Cotypes or Paratypes – A cotype is a second specimen from the same plant from where the holotype was collected. It is occasionally mentioned in the literature.

(f) Syntype – It is one of the two or more specimens cited by an author of a species when no holotype was designated; or a Syntype is any one of the two or more specimen originally designated as types. In most cases, where no holotype was designated, there will also be no paratypes, since all the cited specimens will be syntypes.

            (g) Topotype – It is a specimen collected from the same locality from where the holotype was collected.

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