The genus Dendrobium, one of the largest genera in Orchidaceae, exhibits enormous vegetative diversification. Such a situation has hindered the establishment of consistent classification systems. To clarify phylogenetic relationships in Dendrobium section Dendrobium and allied groups, we performed molecular phylogenetic analyses of 210 taxa. The results showed that many sections are not monophyletic. Most of the morphological characters that have been believed to reflect phylogenetic relationships are, in fact, the results of convergence. Consequently, recircumscription of the infrageneric classification is required.

In the course of revisionary work of Dendrobium section Formosae, we found some misinterpretations of Dendrobium kontumense. Dendrobium schildhaueri is placed as a synonym of D. kontumense and D. roseiodorum, a new species from Vietnam, is described.