STUDIES ON FLORA AND ECOLOGICAL FEATURES OF ENDANGERED PLANT COMMUNITIES IN SONGZIYUAN, THE SOUTHERN SLOPE OF MT.SHENNONGJIA

Flora and ecological features of endangered plant communities distributing in Songziyuan,southern slope of Mt.Shennongjia are studied in the paper.The results show that there are 126 vascular plant species,belonging to 108 genera 64 families in the communities and 9 endangered plant species,accounting for 27.3% of the total amount of endangered plant in Mt.Shennongjia.The communities have temperate character.In physiognomy of community,phanerophytes dominated in life form,is 65.9%;mesophyll in leaf form is 62.7%;herbaceous in leaf texture is 84.15;simple leaf is 83.3%;unentire leaf in leaf margin is 69.8%.Communities have a distinct stratification which can be divided into three layers.Communities can be recognized as three types according to value of importance of species:com.Cercidiphyllum japonicum+Padus wilsonii,com.Davidia involucrata+Litsea pungens,com.Cercidiphyllum japonicum+Acer mono.The index of species diversity of tree layer have little change among communities and evenness are high.The results indicate that the communities have complex structures and now are the relative stabilities.