| Abstract: | ![]()
Chinese flora with many endemic elements is highly important in the world’sflora. According to recent statistics there are about 196 genera of spermatophytes, being 6.5% of total Chinese genera. These endemic genera comprising 377 species belongto 68 families, among which the Gesneriaceae (28 genera), Umbelliferae (13), Compositae (13), Orchidaceae (12) and Labiatae (10) are predominant. The tropical typecontaining 24 families and 80 genera is dominant. After it follows the temperate typewith 23 families and 50 genera. There are also 4 families endemic to China, i.e. Ginkgoaceae, Bretschneideraceae, Eucommiaceae and Davidiaceae. It shows that generaendemic to China are obviously related to the tropical and temperate flora in essence. The endemic monotypic genera (139) and endemic obligotypic genera (48) combined make up more than 95% of the total number of genera endemic to China. Phylogenetically more than half of them are ancient or primitive. The life forms of all endemic genera are also diverse. Herbs, especially perennial herbs, prevail with the proportion of about 62%, and trees and shrubs are the next, with 33%, and the rest are lianas. Based upon the calculated number of genera endemic to China in each province andthe similarity coefficents between any two provinces, some conclusions may be drawnas follows: Yunnan and Sichuan Provinces combined are the distribution centre of genera endemic to China and may be their original or differentiation area, because numerousendemic genera, including various groups, exist in these two provinces. The second isGuizhou where there are 62 endemic genera. Others form a declining order, southChina, central China and east China. But towards the north China endemic genera decrease gradually, and the Qinling Range is an important distributional limit. The largest simitarity coefficient, over 50%, appears between Shaanxi and Gansuprobably because of the Qinling Range linking these two provinces. But between anyother two provinces it is less than 30% and it is generaly larger between two south provinces than between two north provinces. These characteristics mentioned above are correlated with topography and climate,and they may be resulted from the diversification in geography and climatic influencefor a long time. |
