Format: ORAL

Warren Cardinal-McTeague1,2, Kenneth Wurdack3, Lynn Gillespie2

1 Department of Forest & Conservation Sciences, University of British Columbia, Vancouver, Canada 2 Research & Collections Division, Canadian Museum of Nature, Ottawa, Canada 3 Department of Botany, Smithsonian Institution, Washington, USA

Plukenetieae subtribe Tragiinae (Acalyphoideae) is a pantropical and subtropical lineage of ~14 genera and ~200 species of primarily twining vines characterized by their small unisexual flowers with diverse pistillate and androecial morphology, exceptional pollen morphology (including trends towards aperture reduction and loss), and stinging hair defenses. Tragia (~160 species) is one of the larger genera of Euphorbiaceae and has a complex sectional classification that until recently included several small genera that are now recognized as distinct (e.g., Bia, Ctenomeria, Monadelpha, Zuckertia). It was hypothesized that several more of the sections of Tragia could be resurrected as genera but only upon the careful assessment of molecular and morphological data. Using Bayesian phylogenetics on a concatenated dataset of nuclear ribosomal (ETS, ITS), nuclear low-copy (TEB), and plastid (matK, ndhF) DNA, we produced a robust and well-resolved phylogeny for Tragiinae. Tragia is strongly supported as paraphyletic with many subclades that could be recognized as distinct genera. Here, we outline our revised generic classification for Tragiinae, which circumscribes genera by a combination of floral morphology (specifically pistillate and androecial morphology), inflorescence structure, well-defined biogeographic distributions, and palynological evidence.