The International Code of Nomenclature for algae, fungi, and plants sets the rules for how scientific names are formed, published, typified and chosen between. The current edition, the Madrid Code, was accepted by the International Botanical Congress in Madrid in July 2024 and published in 2025 (Madrid Code). Fungi share it with plants, plus a chapter of fungus-only rules.
It is the source of most terms in this part of the glossary. It defines a species name as a genus plus an epithet (Art. 23.1), sets out holotypes, neotypes and epitypes (Art. 9), and lets names be conserved against the usual priority rules (Art. 14.1); Psilocybe is one such conserved name. Since 2013, new fungal names must cite an identifier from a recognized repository (Art. F.5.2).
The Code regulates names, not biology. It does not say which species exist; that is a scientific judgement, and authorities can disagree. It also does not cover cultivated-plant names, which have a separate code, and it gives no standing to the informal labels used for cultivated mushrooms.
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