Dissertation Research: Systematics and Floral Morphology Evolution in the Genus Piper (Piperaceae)

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9972600Manos and Jaramillo Graduate student Alejandra Jaramillo, under the direction of Dr. Paul Manos at Duke University, is studying the taxonomic classification of the large genus Piper (the genus of black and white pepper, with ca. 1200 species) and the development of floral morphology in several species of this tropical group. Piper species occur as shrubs, lianas, and herbs in the understory and canopy of tropical forests worldwide. Although individual Piper flowers are minute, the species express a wide range of diversity in unisexual and bisexual forms, including various types of perfect flowers that differ in the number and positional relationships of their stamens. However, patterns of floral variation have not been independently tested as reliable indicators of phylogenetic (or genealogical) relationship. This project will emphasize the DNA sequencing of both nuclear and chloroplast genes as sources of evidence to construct a framework phylogeny for ca. 130 species representative of the subgenera and geographical diversity known for the genus, in order further to study ontogenetic (developmental) stages in flower morphology. Ontogenetic modifications, such as dioecy and extreme stamen reduction, will be mapped onto phylogenies to test the association between floral innovation and diversification across the genus. Phylogenetic analysis will also improve the subgeneric and sectional classification of this large genus, and help advance improved species-level delimitation. An improved understanding of the evolutionary history of Piper provides an opportunity to identify key floral innovations in the diversification of the largest genus of "primitive" dicots.