关键词: 雅鲁藏布江大拐弯, 蕨类, 植物区系

Abstract: The pteridophytic flora from the Big Bend at Yalu Tsangpo (River)comprises 108 gebara,45 families.The representative families are Dryopteridaceae(80/5,No.fo sp./No.of gen.),polypodiaceae (65/14),Athyriaceae(45/11),Aspleniaceae(23/3),Sinopteriddaceae (19/6).Thelyptedaceae (18/9),pteridaceae (13/2),Selaginellaceae (12/1) and Hymenophyllaceae(11/3).The main genera are polystichum ,Dryopteris,Asplenium,Athyrium, and some genera in polypodiaceae,which are some phy-logenically higher taxa;and in thos flora,there are on typical gernera which are endemic to this region It can de said that the pteriophytic flora of Yalu Tsangpo (River)Big Bend is a younger area one which devel-oped with the heaving of the Qingzang Plateau .It is rich that the families (62.2% to total )and genera (67.6% to total)are tropical taxa,but the top families and genera are cosmopolitan taxa This pteriophyti flora developed from an ancient one of tropical Asia.

Key words: The Yalu Tsangpo (River)Big Bend, Pteriophyta, Flora