A new species of Roscoea from Bhutan and southern Tibet, R. bhutanica Ngamriab., formerly included in R. tibetica Batalin, is described and a new key to all species of Roscoea is provided. While studying the phylogeny of Roscoea, we discovered that there is a correspondence between phylogeny and biogeography (Ngamriabsakul et al., 2000). There are two distinct areas of distribution in Roscoea, namely the Himalaya and China. Only R. tibetica has been recorded in both areas. Cowley (1982) indicated that this species was very variable and suggested that it might be divided. We now propose to name a new species, R. bhutanica, based on observation of living and herbarium material at the Royal Botanic Garden Edinburgh (RBGE) and a molecular systematic study. A morphological table comparing R. tibetica with R. bhutanica is given, along with the ITS sequences of R. tibetica, R. bhutanica and R. auriculata. The identification key to Roscoea species largely follows our phylogenetic tree (Ngamriabsakul et al., 2000).
