Cheilocostus phuongii (Costaceae), an unusual new terminally flowering species from central Vietnam

Summary A new and unusual spiral ginger (Zingiberales: Costaceae) from Bach Ma National Park, Thua Thien Hue province, central Vietnam is described. Cheilocostus phuongii differs from all known terminally flowering species of Cheilocostus by its completely glabrous stems and leaves, bright yellow flowers, and fruits with only a few large non-angular seeds. A detailed description, colour plates, notes on recognition, distribution, habitat, phenology, etymology and morphological affinities with other congeners are given. The key to Cheilocostus in Vietnam is updated. The species is provisionally assessed as Endangered.