Florogeography of mire plants in southern part of qinghai-xizang plateau and its adjacent areas

Abstract

The southern part of the Qinghai-Xizang (Tibet) Plateau and its adjacent area are rich in mire flora. There are 51 families, 101 genera and 220 species. The geographical compositions of this region are very complex, consisting of the following-geographical elements: tropic-subtropic elements approximating to 8.33% of the entire flora in the region, tropic-temperate elements 22.71%, temperate elements 43.18%, cosmopolitan elements 9.85%, the Qinghai-Xizang endemic elements 14.39%, north polemountain elements 1.51%. Temperate elements in this region are dominant. The dominant species of mires, Carex lasiocarpa, in this region is also found in northeast China, Finland and North America. The origin of mires of this region is earlier than northeast China and Finland. This shows that the southern part of the Qinghai-Xizang Plateau and its adjacent areas may be the centre of the origin and distribution of temperate elements.