FLORA OF SEED PLANT IN RIPARIAN ZONE OF XIANGXI RIVER CATCHMENT IN THREE GORGES AREA

Of the known vascular plants, 127 families, 404 genera and 633 species (including taxa below the species level) were found along the riparian zone based on plot investigation. It included 9 families, 11 genera , and 12 species of the pteridophyta, 118 families, 393 genera,and 621 species of the seed plants. Of seed plants, there were 4 families, 8 genera , and 9 species of gymnosperm, 114 families, 285 genera, and 612 species of angiosperm. Among the plant taxa at the riparian zone, it accounted for 65.8% of Shennongjia Region in family level, 47.3% in genus level, and 26.7% in species level. The high level taxa of vascular plants are rich at the riparian zone in Xiangxi River Catchment. There are 29 protected plant species distributing along the riparian zone.In the component of the flora, the area-types of families were mainly tropical; and of the genera chiefly temperate. The component of flora in riparian zone was similar to that of Shennongjia region. The result showed that the riparian zone has an important role in maintaining regional biodiversity.