Abstract: This paper deals with the floristic comparison and analysis of the alpine region where high-er than 4200 meters above sea level in the Qinghai-Xizang(Tibet) Plateau. Due to the special physio-geographical environments, the zonal vegetation types of this region mainly include alpine scrub, alpine meadow, alpine grassland and alpine scree, spare vegetation, but the plant species are relatively rich, amounting to 1816 species and 204 infraspecific taxa (variety, subspecies and form) of 339 genera and 67 families of seed plants. Based on the phytogeographical, systematical and paleobotanical researches and analysis of the whole flora and the cytological observations of 57 spe-cies, the flora of this region is characterized by its temperate nature, a close relationship with Sino-Himalayan flora and a young flora with complex origin history which was formed gradually during the uplifting of the Himalayas and the Qinghai-Xizang Plateau.

Key words: Qinghai-Xizang Plateau

摘要： 研究了青藏高原海拔4200m以上大体是林线以上的高寒地区的种子植物区系。这一地区自然条件恶劣，地带性植被为高山灌丛、高寒草甸、高寒草原、荒漠化草原和冰缘植被，然而植物区系仍比较丰富，共有种子植物67科，339属，1816种及204个种下等级（变种、亚种、变型）。对这些属种的地理分布、系统演化关系以及这一地区的古植物学资料进行了分析研究；对57种进行了细胞染色体的观察。认为本区系是一个温带性质的植物区系，与中国-喜马拉雅区系关系密切，在喜马拉雅和青藏高原隆起的过程中逐渐形成，是一个年青的区系，但有着久远的历史渊源。

关键词: 青藏高原, 高寒地区, 种子植物, 区系