Taxonomic Revision Of The Salix Alfredii Complex(Salicaceae)

Salix alfredii complex belongs to the genus Salix L.(Salicaceae).Nine species and four varieties have been recognized in this complex involved in three section,namely,S.heterochroma Seemen,S.hypoleuca Seemen,S.hypoleuca var.Playphylla Schneider,S.polyclona C.K.Schneider,S.rhoophila C.K.Schneider,S.mictotricha C.K.Schneider,S.alfredii Goerz,S.alfredii var.fengxianica(N.Chao)G.H.Zhu,S.wuiana K.S.Hao ex C.F.Fang&A.K.Skvortsov,S.shimenensis N.Chao&Z.Y.Wang,S.taishanensis C.Wang et C.F.Fang,S.taishanensis var.hebeinica C.F.Fang,,S.caprea var.subsessilis K.S.Hao ex C.F.Fang&A.K.Skvortsov,which is distributed in Hebei,Shanxi,Shaanxi,Shandong,Gansu,Hubei,Hunan,Sichuan ect.The current taxonomy of this complex which shows a wide morphological variation during development stage is unsatisfactory probably because it has been based on few available specimens in the herbaria without extensive field observation and population sampling.The variation ranges of the characters are unclear and the delimitation of some taxa is unjustified.The main purpose of this study is to elucidate the interspecific and intraspecific relationships among taxa within this complex,a comprehensive taxonomic revision will be conducted.These investigations will provide insights for understanding taxonomic problem existed in the genus Salix and a good reference to analyze and solve classification of the genus Salix.Based on the literature,we examined a large number of specimens preserved in A,GH,E,K,LINN,MO,NY,P,S,US,CCNU,HIB,PE,SZ,WH,WUK.and conducted regular population sampling to observe the process of character variation during cycle of great useful to evaluate taxonomic value of characters and solve the classification problem of the complex.As a result,The lectotype of S.rhoophila is designated and S.rhoophila is treated as synonyms of S.hypoleuca.S.heterochroma and S.hypoleuca are separated from the S.polyclona complex,and only one species,S.polyclona is recongnized.