Slow progress in mending the laws of botanical nomenclature

Accuracy and clarity in the names of species are achieved through globally agreed rules: the various international codes of nomenclature. For plants, proposed amendments to these rules¹ are debated during a week-long side meeting of the International Botanical Congress, which is held once every six years — most recently in Madrid in mid-July 2024 (ref. ²). Amendments accepted by delegates to that meeting will be included in the next published International Code of Nomenclature for Algae, Fungi, and Plants (hereafter, Code), due in 2025. Three controversial issues were considered at the 2024 International Botanical Congress, two of which focused on addressing ethical issues that arise from historical nomenclature and one of which aimed at future-proofing the type method to ensure that biological nomenclature is able to continue to accurately document and name the Earth’s biodiversity.

In the end, modest decisions were taken with respect to the first issue, which addressed eponymy — the common practice of naming taxa in honour of significant individuals. Eponyms capture and permanently record noteworthy — and sometimes troubling — aspects of the history and social context of the science of taxonomy. A set of proposals³ considered by the Madrid meeting provided a mechanism by which problematic eponyms, such as those that honour traders of enslaved persons or colonial administrators who were responsible for genocidal policies and acts, could be retired and replaced by more appropriate and acceptable names. When first published in 2021, these proposals sparked controversy: some argued that they would throw nomenclature into disarray by opening a floodgate of re-namings. By the opening of the Madrid meeting, the proposals had polarized the community. By the end of the meeting, a decision had been reached (the required 60% supermajority had been achieved) to amend the Code to allow the rejection of names that are derogatory to a group or groups of people, but only for names published after 1 January 2026. Although this decision recognizes that derogatory names are unacceptable, the meeting attendees demurred from establishing a way to deal with historical derogatory names. A special committee was established to report to the next meeting (in Cape Town, South Africa, in 2029) on how best to deal with matters of ethics in botanical nomenclature. The committee, once established, has an important but challenging remit — to find an appropriate way forward in a contested space.