虎尾草亚科系统发育关系的初步研究

The Phylogeny of the Chloridoideae （Gramineae）： A Cladistic Analysis

摘要:

运用广义形态学性状对虎尾草亚科（Chloridoideae）进行系统发育分析。内类群包括虎尾草亚科52属的69种植物，代表虎尾草亚科的主要类群；芦竹亚科（Arundinoideae）扁芒草族（Danthonieae）的Centropodia和Danthonia被选作外类群。分支分析表明，虎尾草亚科是一个单系类群。其严格一致树包括A、B、C、D、E 5个分支。两个大族画眉草族（Eragrostideae）和虎尾草族（Chlorideae）代表虎尾草亚科内部类群分化的两个方向，分开处理较合理。细穗草族（Leptureae）放到虎尾草族中较合理。冠芒草族（Pappophoreae）是虎尾草亚科的基部类群，与画眉草族近缘。我们的研究支持虎尾草亚科从旧世界向新世界扩散的地理分布假说，并提供了虎尾草亚科属上类群的系统发育关系的框架。

Abstract:

One hundred of morphological characters of 69 species （representing 52 genera and all tribes and subtribes of the subfamily Chloridoideae of Gramineae） are used to reconstruct the phylogeny for the Chloridoideae. Cladistic analysis show that the monophyly of Chloridoideae and its origination from danthonoid group are supported. Five clades are found in correlation with traditional classification systems. Clade A comprises 2 genera of Pappophoreae, clade B 5 genera of Eragrostideae, clade C 6 genera of Eragrostideae, clade D 9 genera of Eragrostideae, and clade E comprises 8 genera of Eragrostideae, 9 genera of Chlorideae, and 1 genus of Leptureae. The two largest tribes Eragrostideae and Chlorideae turn out to be polyphyletic. The Chlorideae affinity of Leptureae is substantiated in the cladistic study. The basal tribe Pappophoreae may provide a link between the chloridoids and the danthonoids. A pattern of segregation of species from Old World to New World is evident in several clades. These results provide a framework for further studies at the supra-generic levels moving toward to a comprehensive systematic treatment of the Chloridoideae.