摘要
本文运用支序分类的原理和方法,对龙胆科龙胆属的属下等级进行了重新归类和系统发育分析。龙胆属是一个单系群,以3项近裔共性为归类依据。性状分析作了性状同源性分析和性状极性分析。性状极化主要以外类群比较、性状相关性及染色体资料为依据,其它方法,如生物重演律原则、地理递进原则以及孢粉形态等也被结合使用。分析结果,双蝴蝶属和蔓龙胆属被选择为外类群,71个性状被选择作为建立数据矩阵的基本资料。使用PAUP程序对矩阵进行了运算,得到4个最简约的谱系分支图,它们均具一致性系数0.637,支序长度为160步,f-比值范围为0.179～0.189,其中具最低f-比值的图被选作为类群归类和讨论亲缘关系的基础。在支序图上龙胆属归为15个组;其中5个组又划分为系,共包括23个系,其余组为单型组,故共有33个属下类群。一个严格的一致性谱系分支图总结了所有的一致点,从而支持了支序分析的结果。
A cladistic study was undertaken to make the infrageneric classification and to e-valuate the phylogenetic relationships in the genus Gentiana. As a monophyletic group, Gen-tiana is based on three synapomorphies and includes 23 series and 10 monotypic Sections. Two genera, Tripterospermum and Crawfurdia, were selected as the outgroups. Most character complexes were surveyed and 61 informative characters from morphology, paly-nology and cytology were used for this study. The analysis resulted in 51 equally parsimonious cladograms and the one with the lowest f-value of 0. 213 was selected as the base for discussing cladistic classification and making cladistic analysis. Results of the cladistic classification support most of the current systematic classification of Gentiana, with main differences in the circumscription of some sections (e. g. , Frigida, Isomeria and Chondrophylla). In the cladogram, Gentiana was first split into two clades, the perennial clade and the annual clade. In the perennial clade, Sect. Pneumonanthe emerged earlier and is the most primitive taxon in this genus. Two subclades, the Asian subclade and the European subclade, came out after Sect. Pneumonanthe. The Asian subclade includes eight sections (Cruciata, O-tophora, Frigida, Microsperma, Monopodiae, Kudoa, Phyllocalyx and Isomeria). The first two sections which form the Cruciata-branch diverged at a low level, especially Sect. Cruciata is also a primitive taxon of the genus Gentiana. The remaining sections which constitute the Frigida-branch are more advanced. The European subcjade includes Sect. Gentiana, Sect. Ciminalis and Sect. Calathianae. This subclade is regarded as a relatively isolated and specialized one in Gentiane. The annual clade consists of two sections (Dolichocarpa and Chondrophylla), of which Sect. Chondrophylla is a more advanced taxon. In addition, Sect. Stenogyne was considered to be of a hybrid origin between the two genera Tripterospermum and Gentiana with some characters of its parents. A strict consensus tree summaries the points of agreement in all the 51 equally parsimonious trees. The phylogenetic relationships of the sections and series in the genus Gentiana. are also strongly supported by this consensus tree.
出处
《植物分类学报》
CSCD
1996年第5期505-530,共26页
Acta Phytotaxonomica Sinica
基金
National Natural Science Foundation of China.
关键词
龙胆麦
龙胆属
系统发育
支序分析
Gentiana
Phylogeny
Cladistic classification
Cladistic analysis
