Ancestral gene flow and parallel organellar genome capture result in extreme phylogenomic discord in a lineage of angiosperms

While hybridization has recently received a resurgence of attention from systematists and evolutionary biologists, there remains a dearth of case studies on ancient, diversified hybrid lineages-clades of organisms that originated through reticulation. Studies on these groups are valuable in that they would speak to the long-term phylogenetic success of lineages following gene flow between species. We present a phylogenomic view of Heuchera, long known for frequent hybridization, incorporating all three independent genomes: targeted nuclear (~400,000 bp), plastid (~160,000 bp), and mitochondrial (~470,000 bp) data. We analyze these data using multiple concatenation and coalescence strategies. The nuclear phylogeny is consistent with previous work and with morphology, confidently suggesting a monophyletic Heuchera. By contrast, analyses of both organellar genomes recover a grossly polyphyletic Heuchera,consisting of three primary clades with relationships extensively rearranged within the...