Community Structure and Species Diversity of Rare and Endangered Plants of Davidia involucrata

To further understand Davidia involucrata community species diversity characteristics in Northern Zhaotong, according to the field survey in June,2008 and June,2010,the species composition, structural characteristics and species diversity of D. involucrata Comm.in Northern Zhaotong were analyzed. The results showed that:(1) species are rich within 4 500 m2 plots,there are 190 species of vascular plants which belong to 70 families,121 genera and contain more ancient, endemic and rare species. (2) Dominance of D. involucrata Comm.is obvious. There are five samples in nine plots of land to D. involucrata single dominant species,the average critical value of 27.83. (3) Species diversity index and Pielou index of shrub layer are lower than those of the herb layer and tree layer, whose features are similar to the warm temperate deciduous broad-leaved forest.