Abstract:

Located in eastern Qinghai， China， the Qinghai Lake basin extends between latitudes 36°15′-38°15′N and longitudes 97°50′-101°45′E at the transition zone between the Qinghai-xizang Plateau and the Loess Plateau， the elevations ranging from 3 160-4 953 m， and the total area encompasses 29 660 km²， and the climate is typified by the alpine continental variety. There were 823 species of seed plants， distributed across 231 genera of 61 families， accounting for 23.13%， 62.89% and 38.82% of the total species， families and genera found in Qinghai respectively. The results of taxonomic analysis indicated that： （1）The density of species in every square kilometer was only 2.78， which was relatively poor compared to the numerous natural areas in the Tangut region. （2）Including the endemic plant species in China， 99.00% of the fauna was temperate， which determined that the fauna was temperate in nature. （3）There were a few woody species， few ancient and primitive groups， yet the flora with perennial herbs as the core. （4）Some of the Chinese endemic species in this region were derived from their extensive relatives， which was a concrete embodiment of the young and derived nature of the region. （5）The North China Autonomous Region and the Southwest High Mountain Region both had different degrees of influence on this region. （6）There were few endemic genera， and the endemic species were primarily aquatic plants， showing the special evolution results of the unique and Hidden domain water wet environment of Qinghai Lake. （7）The core of China’s endemic species belonged to the Gansu-Xizang-Sichuan subtype， which had the highest diversity of species. Within the subregion of plants on the Qinghai-xizang Plateau， this area belonged to the Tangut region.

Key words: Qinghai Lake basin, flora, floristic characteristics, floristic regionalization