Species Diversity of Tetracentron sinense Community on Mt. Emei, Sichuan, China

In this paper,researches are conducted on biodiversity,structure,species composition and floristic geographical composition of Tetracentron sinense community on Mt. Emei by investigating 5 plots, with each plot having a size of 20 m×30 m. The obtained main results have shown that 1) there are 136 vascular plant species belonging to 105 genera of 66 families,in which angiosperm plants are composed of 121 species which belong to 94 genera of 59 families,accounting for 88.97% in total species number. 2) The community contains tree layer,shrub layer,herb layer and inter stratum plants. And the dominant species of the tree layer are Tetracentron sinense,Prunus padus,Acer laxiflorum and Acer palmatum. The species of the shrub layer mainly belong to the families of Alangiaceae,Lardizabalaceae,Theaceae and Poaceae. In the forest floor,the species belong to the general families of Urticaceae,Liliaceae,Dryopteridaceae and so on. And the inter stratum plant contains 3 species. 3) The order for the Margalef index,ShannonWiener index and Simpson index is herb layer > tree layer > shrub layer,while the order for Pielou index is herb layer > shrub layer > tree layer. 4) The curves of species abundance nature logarithm vs species number are significantly different in the tree,shrub and herbaceous layers. 5) On the composition of geographical elements,temperate element takes a predominated position with 56.84% in total genus number in the community respectively,while tropical-subtropical elements account for 28.43%.