Classification and evolution of the family gentianaceae

This chapter reviews research progress and resulting changes in classification in the Gentian family since the worldwide revision in 2002. Currently, the Gentianaceae includes 99 genera and approximately 1,736 species. The tribal classification still stands, but there have been some important changes of genus delimitations based on new evolutionary work. This includes reclassifications of poly- or paraphyletic genera (e.g., Canscora, Centaurium, Fagraea, Sebaea) that have led to the description of new or resurrected genera such as Cyrtophyllum, Duplipetala, Exochaenium, Gyrandra, Lagenias, Limahlania, Klackenbergia, Phyllocyclus, Picrophloeus, Schenkia, Utania, and Zeltnera. New genera have been discovered in South America, including Roraimaea and Yanomamua. Some genera were incorporated into others to preserve monophyly (Cotylanthera into Exacum, Wurdackanthus into Symbolanthus). Bisgoeppertia has been moved to the Potalieae. Unsolved generic delimitation problems remain in Gentianeae-Swertiinae and Helieae. The placement of the enigmatic mycoheterotroph Voyria is still uncertain, but it is likely an isolated, basally placed branch in the family. Recent biogeographic studies that address large-scale distribution patterns, vicariance events, and the significance of these new results are reviewed in this chapter, as are examples of evolutionary research progress within each tribe.