Phylogenetic Studies of DNA and Morphological Variation in the Subtribe Ecliptinae

本文对菊科向日葵亚族进行了系统研究。向日葵亚族约有500-600种，分布于美国南部和东部、墨西哥、中南美洲、非洲和亚洲。这项研究将集中于四个主要问题：阐明该亚族内的主要谱系和关系；澄清该亚族中最复杂、分类上最困难的向日葵属和最大的向日葵属的属下分类；解决该亚族的属系关系和亚族的安置；以及研究南美洲的维贝希纳的进化和辐射模式。这些目标将主要通过收集叶绿体和核糖体DNA限制酶切位点数据以及染色体和形态数据来实现。对这些不同数据集的分支分析将产生该亚族和向日葵亚族中最大的属的系统发育。这些研究的结果，结合最近对向日葵亚科的cpDNA酶切位点的研究(Kim等人)。(1990a)将有助于澄清菊科最大部落之一的亚部落界限和关系。此外，在Verbesina内部属下一级，由此产生的系统发育可以用来构建该属的现代属下分类，并为解决重要的生物地理问题提供基础。

Systematic studies of the subtribe Ecliptinae of the tribe Heliantheae (Asteraceae), a group of about 500-600 species of the Southern and Eastern USA, Mexico, Central and South America, Africa and Asia are proposed. The study will focus on four major problems: elucidation of the major lineages and relationships within the subtribe; clarification of the infrageneric taxonomy of Verbesina, which is the most complex and taxonomically difficult genus of the subtribe and the largest genus of tribe Heliantheae; resolution of generic relationships and subtribal placement of Verbesian; and examination of the patterns of evolution and radiation of Verbesina in South America. These goals will be accomplished primarily be gathering chloroplast and nuclear ribosomal DNA restriction site data, as well as chromosomal and morphological data. Cladistic analysis of these diverse data sets will produce a phylogeny for the subtribe and the largest genus in tribe Heliantheae. The results of these studies, combined with recent cpDNA restriction site studies of the ÕHeliantheae (Kim et al. 1990a) will help clarify subtribal limits and relationships in one of the largest tribes of the Asteraceae. Furthermore, at the infrageneric level within Verbesina, the resulting phylogenies can then be used to construct a modern infrageneric classification of the genus, as well as provide a basis for resolving important biogeographical questions.