Dissertation Research: Molecular and Anatomical Systematics of Leafless Vandeae (Orchidaceae)

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Orchids comprise one of the largest plant families with approximately 20,000 described species. They represent an extremely diverse group of organisms with a worldwide distribution, occurring on every continent except Antarctica. The large tribe Vandeae makes up 10% of the entire family. It possesses several very specialized members that have been evolutionarily reduced to a leafless and often almost stemless state. These plants depend entirely on their green roots for food manufacture. The primary focus of this study is to develop a phylogenetic hypothesis for these leafless Vandeae using molecular evidence from DNA as well as evidence from macro- and microscopic root structure.With the recent spate of molecular data, evolutionary relationships of plant groups are being reestablished and recircumscribed. Surprisingly, Vandeae, a significant group within the orchid family, has been essentially untouched by molecular taxonomists. This study will provide an additional set of characters, which can be used to derive hypotheses of evolutionary relationships. More importantly, questions concerning the evolution of one of the most extreme modes of epiphytism will be answered.