Preliminary Study on Floristic Characteristics and Ecological Adaptability of Vascular Plants in the Special Eco-environment of Canyon in Dehang,Hu'nan

The floristic characteristic and adaptation of vascular plants in the special eco-environment of canyon in Dehang(Hu'nan Province,China) were analyzed and discussed in this paper.The results show that there are 148 families,566 genera,1 162 species vascular plants in this region.90 species belonging to 21 families and 44 genera are Pteridophyte plants(7.7% of the total species),only one species represents one genus in a family of Gemnosperm,and 1 071 species belonging to 126 families,521 genera are Angiosperm plants(92.2% of the total species) including 704(60.6%) herbs and 458(39.4%) woody.The flora of the special eco-environment in the valley region plays an important role and reflects the nature and characteristic to the flora of Dehang.There are 160 canyon eco-environment obligate species belonging to 71 families and 121 genera in the canyon,it contains 23 genera in 15 families with 36 species are Pteridophyte,124 species are angiosperm(in which there are 11 species of monocotyledon and 113 species of dicotyledonous),including 102(63.7%) herbs,26(16.3%) shrubs,21(13.1%) trees and 11(6.9%) lianas.Most of the species in the herb layer and the shrub layer are the obligate species,seldom in the tree layer in community in canyon area.The canyon eco-environment obligate species evolved series of ecological characters adapted the special environment on the growth type,organ morphology,life history,ecological adaptation groups and areas of ecological adaptation in Dehang.With the succession of plant community,the obligate plants increased,and then reduced in the later stage.