| Summary: | The Campanulaceae are a diverse clade of flowering plants, encompassing more than 2300 species, inhabiting myriad habitats from tropical rainforests to arctic tundra. Using a phylogenetic framework, I inferred the placement and timing of major biogeographic, genomic, and morphological changes in the history of the group. This study highlights the diversity and complexity of historical processes driving evolution within the Campanulaceae from broad, global patterns to shallow, species-level processes in the Mediterranean Basin. First, a robust, multi-gene phylogeny, including all major lineages, is presented to provide a broad, evolutionary perspective of this clade across six continents. Ancestral range estimation supports an out-of-Africa diversification following the KPg extinction event. Chromosomal modeling provides evidence for numerous genome-wide duplication events prior to movements into new, and often harsh, habitats. Morphological reconstructions support the hypothesis that switches in floral symmetry and anther dehiscence were important in the evolution of secondary pollen presentation mechanisms. The Mediterranean Basin is among the most biologically diverse areas in the world, harboring enumerable poorly understood, species-rich groups. Here, I focus on the Roucela complex (Campanula subgenus Roucela), 12 annual species found primarily in the eastern Mediterranean Basin. Plastid and low-copy nuclear markers were employed to reconstruct evolutionary relationships and provide insights into patterns of endemism and diversification through time. Diversification of the Roucela clade appears to have been primarily the result of vicariance driven by the break-up of an ancient landmass. Contrary to past studies, my findings suggest the onset of the Mediterranean climate has not promoted diversification in the Roucela complex and, in fact, may be negatively affecting these species. Because cryptic diversity was detected within the currently recognized, widespread species, Campanula erinus, I used a Hyb-Seq approach to obtain two genomic datasets (nuclear and plastome) across 105 C. erinus individuals, representing 27 populations spanning the Mediterranean Basin. Two lineages were recovered: a western Mediterranean tetraploid lineage and an eastern Mediterranean octoploid lineage. Nuclear gene tree topologies and network analyses indicate a hybrid origin for the octoploid. The Cretan endemic C. creutzburgii (tetraploid) and the western Mediterranean C. erinus (tetraploid) are implicated as parental lineages.
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