XVI International Botanical Congess

Gentianales is one of the core orders of the Asteridae II, consisting of approximately 16 500 species from 1200 genera and five families. With last years advances in molecular systematics several of the issues regarding circumscription and delimitation of Gentianales have been clarified. Among these we find the exclusion of Buddlejaceae, the reclassification of the genera Nuxia and Retzia to Stilbaceae of the Lamiales, as well as the restricted circumscription of Loganiaceae now forming a well supported group consisting of 13 genera. Additional support is also found for the transfer of the tribe Potalieae to the Gentianaceae and for the reduction of Asclepiadaceae as a part of the Apocynaceae. Furthermore, we retrieve no support for the retention of the recently proposed families Geniostomataceae and Strychnaceae. In our circumscription the Gentianales consist of the families Apocynaceae, Gelsemiaceae, Gentianaceae, Loganiaceae, and Rubiaceae.