木兰科的分支分析

A CLADISTIC ANALYSIS OF MAGNOLIACEAE

摘要:

主要以形态学、解剖学、细胞学为依据,以德坚木属为外类群,用分支分析的方法探讨了木兰科属间的系统发育关系.有23个分支单位,选取32个性状,根据外类群比较原则和化石地层学资料,确定了性状的祖征和衍征。对数据矩阵的分支分析使用PAUP3.1.1和Hennig 86 v.1.5分别在Macintosh和IBM机上运行,前者以启发法,后者以BB命令运算,经严格一致化处理,得到一致化分支图。结果表明:1)木兰属为一复系类群,其中sect.Maingola与木莲属形成姊妹群,sect.Theorhodon与盖裂木属接近；2)长蕊木兰属与含笑族种类形成单系类群；3)鹅掌楸属是木兰科中一个特殊类群,很早就分离出来,独自发展。

Abstract:

This paper presents the results of a cladistic analysis and the evaluation of intergeneric phylogenetic relationships within the Magnoliaceae based on morphological, anatomical, and cytological data. In the cladistic analysis, the genus Degeneria is chosen as outgroup. The outgroup comparison method and the fossil evidences are used in polarizing the characters. A data matrix consisting of 23 taxa and 32 characters is analyzed using PAUP 3.1.1 in Macintosh computer and Hennig 86 v. 1.5 in IBM computer, and 44 equally most parsimonious cladograms are produced. The strict consensus cladogram shows that：(1) the genus Magnolia is a polyphyletic group，in which sect．Maingola has a sister-group relationship with the genus Manglietia，and sect．Theorhodon has a close relationship with the genus Talauma；(2) the genus Alcimandra and the tribe Michelia form a monophyletic group；(3) it supports that the genus Liriodendron is isolated in Magnoliaceae and has been branched off from the ancestor of the family in an early stage and it developed in its own pattern．