Dissertation Research: The Systematics and Biogeography of Menodora

University Of Texas At Austin, Austin TX

Investigators

Abstract

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.