Recircumscription and revision of the genus vanoverberghia (Zingiberaceae)

Abstract

The genus Vanoverberghia currently includes three species namely V. sepulchrei and V. rubrobracteata from the Philippines and V. sasakiana from Taiwan. New material targeting the Alpinia eubractea clade of the tribe Alpinieae was used to test the monophyly of Vanoverberghia. A combined analysis of the ITS and trnK/matK regions reveals that these three species form a strongly supported monophyletic clade with Alpinia diversifolia and Alpinia vanoverberghii. The morphological descriptions of all species were updated after examining recent collections and comparing with types and protologues. The original description of A. diversifolia did not include information on the flowers which are described here. The morphology of A. diversifolia and A. vanoverberghii is for most parts in accordance with the previous perception of the genus but a few characters are added and a recircumscription of Vanoverberghia is subsequently provided here. Vanoverberghia diversifolia is reinstated and A. vanoverberghii is combined in Vanoverberghia. Furthermore, collections from northern Luzon documents the presence of V. sasakiana and all species of Vanoverberghia thus occur in the Philippines. A key to the five species is provided including a comprehensive taxonomic revision and designation of three lectotypes.