Modern and Geological Distribution of Castanopsis (Fagaceae)

Modern and geological distributions of Castanopsis,(Fagaceae),are studied based on published data from both botany and palaeobotany,and herbarium records.There are 110 to 134 modern species in genus Castanopsis,and the species are mainly concentrated in Eastern and Southeastern Asia,especially rich in the floristic region of Indo-China with 82 species.There are 29 species endemic to Malaysian region,the richest endemism region of this genus.This fact supports the result from molecular research that floristic migration in this region is limited.The floristic region of Dian (Yunnan)-Qian (Guizhou)-Gui (Guangxi) has the highest Castanopsis species diversity in China,with 29 species.The Indo-Chinese Peninsula and Malaysia may be considered as two modern centers of diversity of this genus.If genus Chrysolepis is excluded,the distribution type of Castanopsis is of tropical Asia.The earliest and reliable records of Castanopsis were back to Eocene,and the subfamily fossil records found from Paleocene,which indicated that the appearance of Castanopsis is not later than Paleocene.All fossil records of Fagaceae including Castanopsis reported from the Northern Hemisphere and their main modern distribution regions are also in the Northern Hemisphere.Thus,it may be concluded that the Northern Hemisphere is the original place of Fagaceae and Castanopsis.