The Flora of Seed Plants in Northern Zhaotong,Yunnan Province

Northern Zhaotong is located at the intersection of Yunnan,Guizhou and Sichuan Provinces,where floristic study was rarely dealt with.Based on over 4 500 specimens collected from this area in 2006,the floristic characteristics at the levels of family,genus and species were analyzed for the first time.The results showed that:1) There were totally 1 864 species of seed plants belonging to 640 genera and 159 families,indicating that the flora is rich in species and diverse in geographical elements.2) The flora showed an obvious temperate feature.There were 127 genera of North Temperate elements,99 genera of pantropic elements,93 genera of East Asian elements and 54 genera of Tropical Asian elements.These four distribution types,which stood for 60.94% of the total number of genera,are the main components of the flora.3) The flora was more similar to that of Fanjingshan Mountain,belonging to the Central China Region,than to that of Xiaobaicaoling(located at central Yunnan Plateau),and belongs to the Central China Region of Sino-Japan Forest Subkingdom.4) There are 10 families endemic to East Asia,1 family endemic to China,27 genera endemic to China,1 063 species endemic to China(accounted for 57% of the total species).The abundant endemic elements indicated that the flora is ancient and unique.It is suggested that the flora,with a deep tropical Asian historical background,is a part of the Central China flora.