Dissertation Research: The Systematics and Biogeography of Menodora

德克萨斯大学奥斯汀分校的Robert Jansen博士和Timothy Chumley先生获得了一笔资助，用于研究橄榄科Menodora植物属的生物地理和进化历史。它在北美、南美和非洲南部的温带干旱地区有着不同寻常的分布，与经济上重要的茉莉最密切相关，茉莉严格地属于旧大陆。关于非洲和北美之间的生物联系的研究相对较少，而且大多数研究都集中在热带而不是温带。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、分化和辐射问题的绝佳系统。在试图确定该属的起源和地理历史时，也有必要了解其物种的历史关系。物种之间的形态相似性可能是生态选择的结果，而不是共同祖先的结果，这一可能性使情况变得复杂。在某些情况下，物种的界限也并不明确。本研究的目标是：1)利用形态学和DNA序列数据研究Menodora之间的关系；2)探索其起源和生物地理学的假设；3)产生一个新的物种分类和专著。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，并为该组的未来工作提供基础。对Menodora的分离的研究将为新大陆和非洲温带植物区系的关系提供新的见解。这些见解可能有助于识别与更大、更多样化的群体或具有更高分类水平的群体共享的生物地理模式，这些群体存在较难处理的问题。

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.