Fig. 1.

Chronogram of the phylogeny of Andropogoneae produced in BEAST (57). Branch colors indicate Bayesian posterior probability with red highest, green lowest. Numbers, allotetraploidization events; letters, allohexaploidization events; black dots, common ancestors of the parental genomes of the polyploids; gray dots, accessions with large, likely polyploid, genome sizes but without evidence of genetic allopolyploidy; shading, approximate time of the Miocene grassland expansion. The order in which the hexaploid genomes came together is unknown; for clarity, they are drawn as though a tetraploid formed from the most closely related parents, and the hexaploidy event added the more distant one, but this is merely a graphical convention.