Floristic Geography of Piper (Piperaceae) in China

Piper is the largest genus and important Pantropical components of the Piperaceae family with approximately 1000-2000 species in the world. China is in the northern verge of its natural distribution. In this study, floristic geography of the Piper genus in China was analyzed to reveal its botanical characteristic, origins of speciation and its dispersal channels. The study results showed Yunnan province is one of the very important distribution regions for Piper species, served as the center of the Piper species dispersal toward to the eastern and northern regions of China with gradually reduced species numbers. The similarity level appeared to be low for its species among different provinces, and the Piper distribution regions could be approximately clustered into three clades: tropical clade, subtropical clade and Taiwan clade. Cladistically, Piper species found in China have the highest proportions which were endemic to China, and then followed by Piper species distributed in Tropical Asia, only few species belonged to Pantropical and East Asia areal types. The floristic geography of Piper genus in China is related to that of Indo Chinese Peninsula, Java Islands and Indian Peninsula in some degrees, but not closely related. This study revealed Yunnan province is one of the central of origins for the Piper species, and or one of the central of regions for its species diversification, and the Piper species of Taiwan mainly came from Philippine islands and further diversified into Taiwan clade. Our study results presented a useful method for the systematic studying of Piper genus taxonomy and the evolution of Piper speciation.