Abstract:

The genus Rhododendron possesses 58 species,2 subspecies and 8 varieties in Dulongjiang region and these species belong to 6 subgenera. Among them, 1 / 4 are compara-tively more primitive species. There are not many alpine groups and species in this region . which demonstrates that this area is old in geological age and less influenced by the uplift of Qinghai-Xizang Plateau. There are 9 epiphytic species along the river valley which reflects the relic of the tropical ecological enviroment. By the analysis of the endemic species and the distri-bution of other species, this region is regarded as an independent floristic area different to the Hengduan Mountains and Qinghai-Xizang Plateau, but has a close relationship with northeast Burma and its adjacent south-east Xizang. In geological history, they might belong to the same old massif.

Key words: Rhododendron. Floristic composition, Dulongjiang