International Botanical Congress

The current numbering system for the congresses starts from the year 1900; the XX IBC was in Madrid, Spain, July 2024.

Formally the power resides with the Plenary Session; in practice this approves the decisions of the Nomenclature Section.

The Nomenclature Section meets before the actual Congress and deals with all proposals to modify the Code: this includes ratifying recommendations from sub-committees on conservation.

To reduce the risk of a hasty decision the Nomenclature Section adopts a 60% majority requirement for any change not already recommended by a committee.

The fourth congress, which had as one of its principal purposes to establish laws of botanical nomenclature, was organized by la Société botanique de France, and took place in Paris in August 1867.