Dissertation Research: The Systematics and Biogeography of Menodora

得克萨斯大学奥斯汀分校的Robert Jansen博士和Timothy Chumley先生获得了一项拨款，用于研究橄榄科植物Menodora的生物地理和进化史。它在北美、南美和南部非洲的温带干旱地区有不寻常的分布，与经济上重要的茉莉花关系最密切，严格来说，茉莉花是东半球的一类。关于非洲和北美之间的生物联系的研究相对较少，而且大多数研究集中在热带而不是温带的分离上。物种数量少，缺乏生态多样性，使Menodora成为研究物种在大陆尺度上的地理传播、分歧和辐射问题的一个极好的系统。在试图确定该属的起源和地理历史时，了解其物种的历史关系也是必要的。物种之间的形态相似性可能是生态选择的结果，而不是共同的祖先，这让情况变得复杂起来。在某些情况下，物种的边界也绝不是清晰的。这项研究的目标是：1)利用形态和DNA序列数据检查Menodora内部的关系，2)探索其起源和生物地理学的假说，3)产生其物种的新分类和一本专著。这项研究将大大增加一个经济上重要的植物科的知识体系，并为该小组未来的工作提供基础。梅诺多拉的分离研究将为新大陆和非洲温带植物群的关系提供新的见解。这些见解可能有助于识别与更大、更多样化的群体共享的生物地理模式，或者更高分类水平的群体，这些群体提出的问题不太容易处理。

A grant has been awarded to Dr. Robert Jansen and Mr. Timothy Chumley at the University of Texas at Austin to research the biogeographic and evolutionary history of the plant genus Menodora in the olive family. It has an unusual distribution in the temperate arid regions of North America, South America and southern Africa, and is most closely related to the economically important jasmines, a group strictly of the Old World. There have been relatively few studies of the biotic connection between Africa and North America, and most of these have focused on tropical rather than temperate disjunctions. The small number of species and lack of ecological diversity make Menodora an excellent system for examining questions of the geographic spread, divergence, and radiation of species across continental scales. In attempting to determine the origins and geographic history of the genus, it is also necessary to understand the historical relationships of its species. This is complicated by the possibility that morphological similarity between species may be the result of ecological selection rather than shared ancestry. In some cases as well, species boundaries are by no means clear. The goals of this study are to: 1) examine relationships within Menodora using morphological and DNA sequence data, 2) explore hypotheses of its origin and biogeography, and 3) produce a new classification of its species and a monograph. This study will add substantially to the body of knowledge of an economically important plant family, and provide a base for future work in that group. The study of disjunction in Menodora will provide new insights into the relationship of the temperate floras of the New World and Africa. These insights may serve to identify biogeographic patterns that are shared with larger, more diverse groups or groups at higher taxonomic levels that present less tractable problems.