Studies on species diversity of vascular plants in the Taizi Mountains forest region

The forest region of the Taizi Mountains, locating in the transitional zone between Tibetan Plateau and Loess Plateau, is located in special geological area and shows obvious diversity in vascular plant species and forest community types. The results of floristic analysis based on inventory data showed as follows: 1.There were 89 families, 306 genera,847 species, and 12 varieties, 4 subspecies, 2 forms of vascular plants, among which pteridophyta included 9 families ,16 genera and 29 species, occupied 3.42 % of the total number of species and spermatophyte 80 families,290 genera,818 species, occupied 96.56 % of the total; 2. The temperate genera occupied 75.1 % of the total number of genus and 81.4 % of the total species, but the tropical genus occupied only 8.53 % and the flora expressed transitional characteristics; 3. The life forms of 719 species had been identified as phanerophytes (Ph) and chamaephytes (Ch), tended to be absolutely dominant life-forms and occupied 87.9 % of the total species; 4. The floristic composition was highly similar to the Maxian Mountains, and the follows were the Lianhua Mountains, the Tao River basin and the Mengda Nature Reserve; 5. The forest region should belong to the floristic subregion of the Northwestern Sichuan-Southwestern Gansu-Southeastern Qinghai of the Hengduan Mountains Floristic Region and could be regarded as the boundary line between this region and the Loess Plateau subregion of the Northern China Region.