Publication Date




Embargo Period


Degree Type


Degree Name

Doctor of Philosophy (PHD)


Biology (Arts and Sciences)

Date of Defense


First Committee Member

Barbara A. Whitlock

Second Committee Member

Carol Horvitz

Third Committee Member

J. Albert C. Uy

Fourth Committee Member

Carl E. Lewis


Plant systematics broadly explores the origins and maintenance of plant diversity on earth. Here I describe four systematic investigations of the plant genus Ayenia, a New World genus of shrubs and subshrubs with approximately 85 species found mostly in dry habitats. In the first chapter, I show that the unusual trithecate anthers that Ayenia and its close relative Megatritheca share are a result of parallel evolution. In the second chapter, I focus on reconstructing the historical biogeography of the genus and thus show that Ayenia originated in South America, but has spread throughout tropical and subtropical America, including at least two independent migrations into the Caribbean islands. In my third chapter, I explore the utility of next generation sequencing techniques for resolving the phylogeny of a rapid radiation of Ayenia, further clarifying the biogeographic patterns leading to its current distribution. Finally, in my fourth chapter, I describe a population genomics study of the northern Caribbean endemic, Ayenia euphrasiifolia, and its potential use as a model system for conservation of an endangered South Florida habitat, pine rocklands. Together, these investigations explore the evolution of a single genus, from a broad multi-genus perspective, to the fine scale of a single species. I use a combination of phylogenetic, phylogenomic, and population genomic techniques in these chapters, and discuss their utility and limitations in rare and understudied systems.


plant systematics; evolution; biogeography; Ayenia; Malvaceae; Byttnerioideae

Available for download on Wednesday, May 06, 2020