关键词: 柳属, 分支系统学, 形态学性状, 系统发育关系

Abstract: The genus Salix comprises about 500 species , many of which grow in temperate zone of the North Hemisphere. Their variability in morphology , life form and habitats has led to many arguments and different suggestions in terms of taxonomical treatments at both species and genus levels . To understand morphological variation and phylogenetics of Salix, 29 Salix species and Chosenia arbutifolia , including most representative species in the genus Salix , and their 61 morphological characters were used for cladistic analysis . Populus plants were selected as outgroups. In this study , we got 21 equally most parsimonious cladograms of Salix and a strict consensus tree, which shows Chosenia is sister group of Salix and those two taxa form a strongly supported monophyletic clade . The results indicate that the division of Chosenia and Toisusu from Salix as independent genera and any other division on the generic level are not supported, which accords with the evidences from both palynology and molecular systematics. Three subgenera, Subgen. Salix, Subgen. Chamaetia and Subgen. Vetrix form two monophyletic clades respectively. Based on our findings, we proposed to divide Salix into three subgenera, namely Chosenia, Salix, Vetrix. Considered there exist the lower Consistency Index, Retention Index and bootstrap value in the phylogenetic tree, more research for better understanding the infrageneric system of Salix should be fully necessary .

Key words: Salix