Phylogenetic, Morphometric, and Biogeographic Investigations of Trema micrantha (Cannabaceae)

Trema micrantha L. Blume (Cannabaceae) is a pioneer tree species that is broadly distributed across the Neotropics. Taxonomic circumscriptions of this group have long been debated and problematic due to its morphological variation and broad geographic range. Delimitation of lineages within T. micrantha has remained unclear as molecular phylogenies with limited character and taxon sampling have not resolved the polyphyly of this group. To evaluate relationships within T. micrantha, I utilized phylogenetic, morphometric, and biogeographic methods. Using various DNA datasets, including ETS only, 5 DNA loci, plastome and whole nuclear ribosomal datasets, the recognition of 9 clades within T. micrantha as species was supported. Leaf shape morphometrics determined that several of these clades are morphologically diagnosable, but with some overlap in leaf shape, while ecological niche models elucidated ecological tolerance differences between clades. I thus evaluated these data across three species concepts for future taxonomic revisions.