Biogeography of the only irises disjunct across the Pacific Ocean.

Sophie S. Newmarch (Massey University); Richard C. Winkworth (Massey University); Dan J. Blanchon (Auckland War Memorial Museum); Joanne L. Birch (University of Melbourne); Nicolás García (Universidad de Chile); Jennifer A. Tate (Massey University).

Taxa with disjunct distributions have long fascinated biologists and have provided important insights into biological evolution in the southern hemisphere. Libertia and Orthrosanthus are two understudied genera, and the only representatives of Iridaceae (~70 genera), that are disjunct across the Pacific Ocean. Both groups naturally occur in South and Central America, and in Australia; Libertia is also found in New Zealand and New Guinea. Previous studies have suggested that Libertia and Orthrosanthus are sister within the tribe Sisyrinchieae, which likely arose in South America ~21.6 million years ago. Since previous studies have included only one species from each genus, their biogeographic origins and distribution remains uncertain. Here we present a dated phylogeny based on a large plastome data set, assembled from a combination of genome-skimming and Angiosperms353 by-catch, that includes representatives of all species of Libertia and Orthrosanthus. The results provide novel insights into the biogeography of these two genera and provide a foundation for further studies into polyploidy and floral evolution.