Format: ORAL

Nora S. Gavin-Smyth1,2, Jeremie B. Fant1,2, Patrick S. Herendeen1,2

Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, USA Plant Biology and Conservation, Northwestern University, Evanston, IL, USA

The Impatiens genus is well known to vary excessively, presenting extensive modifications in floral structure among its 1200 species. Most Impatiens lineages radiated just within the last 3 million years, indicating that these disparate floral forms can evolve rapidly, even among closely related taxa. Phylogenetic relationships in the genus have historically been difficult to intuit based on morphology, given numerous occurrences of convergent evolution, but also difficult to determine based on molecular characters, due to issues such as incomplete lineage sorting and hybridization. We present results of the first target enrichment approach to Impatiens phylogeny, using Angiosperm353 loci. In our tree with over 325 individuals from 250 taxa, we focus on resolving the phylogenetic relationships among African taxa, with a fine-grain focus on the endemic-rich Eastern Arc Mountains of Tanzania and Kenya. We also recovered plastomes for these samples and estimated the chloroplast phylogeny; we found several instances of  discordance with the nuclear phylogeny. In the nuclear phylogeny, we found that endemic-rich clades generally diversify within mountain units in the Eastern Arc Mountains. This indicates ecological speciation in this case, and the important role of limited dispersal ability in Impatiens diversification. Conversely, we found the opposite pattern in the bird pollinated endemic-rich clades. However, the pattern for bird-pollinated taxa is not present in the chloroplast tree.