Abstract: The gensus Arachniodes Bl. in Yunnan was exhaustively studied in the present paper.Through wide field observations and vast herbaria studies, the rhizome habits and the characteris-tics of scales on the base of stipe, such as shape, texture and luster, were found to be relatively sta-ble, which can be used to determine the subdivision of this genus. Some useful characters are the paleae or indument on the frond, the degree of complexity, the shape of the apical part of lamina or that of the basal pinna, the shape and issection of the ultimate pinnule, the texture and luster of lamina, the positions of sori on the pinnule and the edge of indusium, which can be moderately applied to recognize species. The size of frond, lamina or pinna, the angle between rachis and rachlet, the distribution of sori on lamina and so on are unstable characters, which can not correctly define species. As a result, the revised classification of this genus in Yunnan was provided. There are 20 species and 2 varieties, including a new section, 3 new statuses, 6 species and a variety newly recorded to Yunnan and 54 new synonyms from Yunnan and other provinces.

Key words: Arachniodes