Abstract: The geographical distribution and floristic characters of Salix species in Qinghai are studied by means of field survey , examining herbarium specimens and literatures . The result indicates that there are 45 species ( including 5 varieties and 1 form) in Qinghai , they belong to 15 sections, accounting for 100% and 40.9% of species and sections in Qinghai- Tibet plateau , 40.5% and 17.5% of species and sections in China, and take the fourth place in China. They mainly distribute in the Eastern of Qinghai, including the Eastern of Qiliansan Mountain series and the southeastern part of Southern Qinghai plateau, and their vertical distribution concentrates on the altitude 2 000 - 4 000m, it is one of the highest altitude areas of the world that Salix species distribute on. The floristic characters of Salix species in Qinghai Province are as following:1) Rich species; 2 ) High intra specific differentiation; 3 ) Complex geographical components. They are mainly of Eurasia temperate and Qinghai-xizang Plateau distribution, but the component endemic to China plays an important role ; 4) Endemism is not obvious, only accounting for 8.9% of Salix species in Qinghai; 5) Absolute domination with groups of diandrous stamens and monadelphous stamens, accounting for 93.3% of species in Qinghai province. The Salix species in Qinghai Province are closely related to the Eastern (East of Gansu and Shaanxi ) and the southeastern (West of Sichuan , East of Xizang). Because of the continuous lifting of Himalayas and Qinghai-Xizang Plateau since Tertiary, the distribution and floristic characters of Salix in Qinghai, adapting the freezing cold and dried environment, are formed.

Key words: Salix