Instructions for authors of proposals to amend the International Code of Nomenclature for algae, fungi, and plants

The International Code of Nomenclature for algae, fungi, and plants or Madrid Code (hereafter “Code”) was published on 25 July 2025 in print, eBook, and PDF editions (Turland & al. in Regnum Veg. 162. 2025, https://doi.org/10.7208/chicago/9780226839479.001.0001) and on 4 September 2025 in an open-access interactive online edition (https://www.iaptglobal.org/_functions/code/madrid). It incorporates the amendments that were adopted on 27 July 2024 at the XX International Botanical Congress in Madrid, Spain to the previous edition, the Shenzhen Code (Turland & al. in Regnum Veg. 159. 2018). In accordance with its Division (Div.) III Provision (Prov.) 1.2, the Code may be modified only by action of a plenary session of an International Botanical Congress on a resolution moved by the Nomenclature Section of that Congress. The next Congress, the XXI International Botanical Congress, is scheduled to be held in Cape Town, South Africa, in July 2029, with the Nomenclature Section meeting from 16 to 20 July prior to the scientific sessions of the Congress from 21 to 28 July. Anyone proposing amendments to the Code must be familiar with the basic procedure (Fig. 1): 1. After each new edition of the Code appears, proposals to amend it are published in Taxon, where they are numbered serially. 2. Approximately six months prior to the next International Botanical Congress, a synopsis of proposals assembles all published proposals, organized by Article and Recommendation, and republishes them in Taxon with appropriate comments from the Rapporteurs (i.e. the Rapporteur-général and both Vice-rapporteurs) but without the justification accompanying the original publication. 3. A ballot for the preliminary guiding vote (“mail vote”, an entirely advisory opinion from individuals) is sent to those entitled to vote (see Div. III Prov. 2.5) at the same time as the synopsis is published. The completed ballots are tabulated so that the results are available at the Nomenclature Section of the Congress. 4. The Nomenclature Section, meeting ahead of the main sessions of the Congress, considers proposals, including any amendments to them, and acts upon them on the basis of a combination of individual and institutional votes. 5. Decisions of the Nomenclature Section are ratified by vote of a plenary session of the Congress. At this point, the amended provisions take effect. 6. After meticulous editing by the Editorial Committee, the new edition of the Code is published. Further details can be found in Div. III of the Code: Prov. 2 concerns proposals to amend the Code, including the guiding vote; Prov. 3 concerns institutional votes (see below); and Prov. 4 and 5 concern the Nomenclature Section, including its functions, procedure, voting, and the election and appointment of the Rapporteurs and other officers of the Bureau of Nomenclature. The list of institutional votes for the Madrid Congress was published prior to that Congress (Ulloa Ulloa & al. in Taxon 73: 317–324. 2024, https://doi.org/10.1002/tax.13110). However, according to Prov. 3.1, which was amended in Madrid, each listed institution is now allocated one vote. Proposals to amend Chapter F of the Code, or any proposal that deals solely with names of organisms treated as fungi (including fossil fungi), must be submitted to the Nomenclature Session of an International Mycological Congress by publication in the journal IMA Fungus (Div. III Prov. 1.4 and 8.1). In our capacities as Rapporteurs and editors of proposals to amend the Code, we have decided that the following rules shall apply to proposals submitted to Taxon for consideration by the Nomenclature Section of the XXI International Botanical Congress in Cape Town: 1. Proposals that fail to follow these instructions may be rejected for that reason. 2. Taxon will open for proposals on the date of publication of these instructions for authors. 3. Taxon will close for proposals on 31 March 2028. 4. Proposals are to be submitted via the Taxon manuscript submission system (https://wiley.atyponrex.com/journal/TAX); see also 12 below. 5. Proposals to amend the Code at the Cape Town Congress in 2029 must be based on the text of the Madrid Code. 6. Manuscripts must conform to the general standards of Taxon (see “Author Guidelines” at https://onlinelibrary.wiley.com/page/journal/19968175/homepage/author-guidelines), except that the method of citing references follows that of the special “Guidelines for proposals to conserve or reject names” (Wiersema & McNeill in Taxon July 2025, https://www.iaptglobal.org/taxon-guidelines), which are also adopted in the present paper. In questions of format, consult the proposals to amend the Shenzhen Code published from 2020 to 2023 in Taxon (volumes 69–72, see https://onlinelibrary.wiley.com/loi/19968175). 7. The manuscript must have a title that states the aim of the proposal(s), e.g. “Proposals to permit naming of organisms known only from DNA sequences”, not merely referring to the numbering of the Code, e.g. “Proposals to amend Article 7.1 and 40.1”. 8. The manuscript must begin with a concise summarizing paragraph (up to 150 words) clearly explaining the aim of the proposal(s). 9. This must be followed by a second concise paragraph (up to 150 words) assessing the impact to the stability of nomenclature. 10. One or more paragraphs of general explanation may follow (up to 400 words). 11. Manuscripts exceeding these word limits may be returned to the authors for revision. Alternatively, the text may be subjected to a regular review process in order to establish whether the topic that the proposals address is of such importance or complexity as to justify additional space. 12. If a proposal results from a more general context, authors must make that context the subject of a separate paper to be submitted to the Nomenclature column of Taxon (or some other journal), reviewed in the normal way, and considered for acceptance in competition with papers on other topics. Such manuscripts are to be submitted via the Taxon manuscript submission system (see 4 above). 13. These space limitations of 11 and 12 do not apply to reports of Special-purpose Committees appointed to report to the XXI International Botanical Congress (see Turland & al. in Taxon 73: 1312. 2024, https://doi.org/10.1002/tax.13258). Nevertheless, such reports should be written as concisely as possible. They are to be submitted via the Taxon manuscript submission system (see 4 above). 14. Each proposal in the manuscript must state explicitly what amendment is proposed, e.g.: “Insert a new Article after Art. 29.3”; “Delete Art. 46.10”; “Amend Rec. 23A.3 to read as follows (new text in bold, deleted text in strikethrough)”. Proposals must not consist simply of new text or explanation but must indicate precisely what text is to be inserted, deleted, or changed in the Code. This can be achieved by copying and pasting the text from the online edition of the Code and then showing new text in bold and deleted text in strikethrough. 15. When a proposal affects more than one provision of the Code, it should not be divided into separately numbered proposals for each provision affected, but rather grouped into as few numbered proposals as possible. Reordering and renumbering of provisions need not be mentioned because this will be done by the Editorial Committee should a proposal be accepted. 16. Authors will be asked to revise or withdraw proposals that conflict with other parts of the Code or that would cause significant nomenclatural disruption. 17. Proposals to insert, delete, or change Examples (excluding voted Examples; see Art. 7 *Ex. 17 footnote) or Glossary entries will not be accepted for publication in Taxon unless they accompany a proposal to amend an Article, Note, or Recommendation and are important for the understanding of that proposal (because the Editorial Committee can insert, delete, or change Examples and Glossary entries without a proposal; Div. III Prov. 7.12). Instead, they may be submitted directly ([email protected]) to the Editorial Committee, which, prior to the Cape Town Congress, is represented by the Rapporteurs. Proposals that concern only Examples or Glossary entries must follow the rules of 18. 18. If Examples are included, they must follow the format used in the Madrid Code, i.e. with places of publication cited in full. Authors must provide links to online versions of those publications and the protologues of any basionyms, replaced synonyms, or names causing illegitimacy. Online resources include the Biodiversity Heritage Library (https://www.biodiversitylibrary.org/), Biblioteca digital del Real Jardín Botánico CSIC (https://bibdigital.rjb.csic.es/), Gallica (https://gallica.bnf.fr/), Google Books (https://books.google.com/), HathiTrust (https://www.hathitrust.org/), and similar collections. For publications that are not yet online, a scanned copy of the relevant pages (including the title pages) is requested. 1. In general, proposals that contribute to nomenclatural stability are more likely to be successful. 2. Proposals that reduce the complexity of the Code without negatively affecting nomenclatural stability are also likely to succeed. 3. Proposals that address nomenclatural situations that occur only rarely are unlikely to succeed, especially if they add to the complexity of the Code. 4. Authors who feel an urge to write very many proposals to amend the Code should bear in mind the substantial cost in time to the Rapporteurs, the persons participating in the guiding vote, and the members of the Nomenclature Section, all of whom are performing their duties voluntarily. It is therefore recommended that an individual or team does not author more than 50 proposals. The Rapporteurs may decide to reject proposals that disregard this recommendation. 5. Authors are encouraged to provide a list of all the provisions of the Code (Articles, Notes, Recommendations, Examples, etc.) believed to be affected by a given proposal. This helps the Editorial Committee, whose main job is to ensure that any amendments adopted for the new Code are fully integrated with the existing text and consistently implemented throughout. 6. Use of the template Word document (Appendix S1) provided in the supporting information is strongly recommended. Appendix S1: Template Word document for proposals to amend the International Code of Nomenclature for algae, fungi, and plants. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.