International Botanical Congress

International Botanical Congress (IBC) is an international meeting of botanists in all scientific fields, authorized by the International Association of Botanical and Mycological Societies (IABMS) and held every six years, with the location rotating between different continents. The current numbering system for the congresses starts from the year 1900; the XVIII IBC was held in Melbourne, Australia, 24–30 July 2011, and the XIX IBC was held in Shenzhen, China, 23–29 July 2017.

The IBC has the power to alter the ICN (International Code of Nomenclature for algae, fungi, and plants), which was renamed from the International Code of Botanical Nomenclature (ICBN) at the XVIII IBC. 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.