1. Biology requires a precise and simple system of nomenclature that is used in all countries, dealing on the one hand with the terms that denote the ranks of taxonomic groups or units, and on the other hand with the scientific names that are applied to the individual taxonomic groups. The purpose of giving a name to a taxonomic group is not to indicate its characters or history, but to supply a means of referring to it and to indicate its taxonomic rank. This Code aims at the provision of a stable method of naming taxonomic groups, avoiding and rejecting the use of names that may cause error or ambiguity or throw science into confusion. Next in importance is the avoidance of the useless creation of names. Other considerations, such as absolute grammatical correctness, regularity or euphony of names, more or less prevailing custom, regard for persons, etc., notwithstanding their undeniable importance, are relatively accessory.

2. Algae, fungi, and plants are the organisms1 covered by this Code.

[footnote]1 In this Code, unless otherwise indicated, the word “organism” applies only to the organisms covered by this Code, i.e. those traditionally studied by botanists, mycologists, and phycologists (see Pre. 8).

3. The Principles form the basis of the system of nomenclature governed by this Code.

4. The detailed provisions are divided into rules, which are set out in the Articles (Art.) (sometimes with clarification in Notes), and Recommendations (Rec.). Examples (Ex.)2 are added to the rules and recommendations to illustrate them. A Glossary defining terms used in this Code is included.

[footnote]2 See also Art. 7 *Ex. 16 footnote.

5. The object of the rules is to put the nomenclature of the past into order and to provide for that of the future; names contrary to a rule cannot be maintained.

6. The Recommendations deal with subsidiary points; their object is to achieve greater uniformity and clarity, especially in future nomenclature; names contrary to a Recommendation cannot, on that account, be rejected, but they are not examples to be followed.

7. The Provisions regulating the governance of this Code form its last Division (Div. III).

8. The provisions of this Code apply to all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria)3, chytrids, oomycetes, slime moulds, and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia). Provisions for the names of hybrids appear in Chapter H.

[footnote]3 For the nomenclature of other prokaryotic groups, see the International Code of Nomenclature of Prokaryotes. Prokaryotic Code (2008 Revision); DOI:; formerly the International Code of Nomenclature of Bacteria (Bacteriological Code).

9. Names that have been conserved, protected, or rejected, suppressed works, and binding decisions are given in Appendices I–VII.

10. The Appendices form an integral part of this Code, whether published together with, or separately from, the main text.

11. The International Code of Nomenclature for Cultivated Plants is prepared under the authority of the International Commission for the Nomenclature of Cultivated Plants and deals with the use and formation of names applied to special categories of organisms in agriculture, forestry, and horticulture.

12. The only proper reasons for changing a name are either a more profound knowledge of the facts resulting from adequate taxonomic study or the necessity of giving up a nomenclature that is contrary to the rules.

13. In the absence of a relevant rule or where the consequences of rules are doubtful, established custom is followed.

14. This edition of the Code supersedes all previous editions.