Age and biogeography of major clades in Liliales

A robust phylogeny of 40 genera and all seven families of the Liliales based on rbcL sequences was dated by the mean branchlength method of Bremer and Gustafsson and by Sandersonʹs nonparametric rate smoothing. The basal node was set to 82 million years (my) from the results of a previous more extensive dating involving all monocots. Confidence intervals for the age estimates were generated by bootstrap analysis. The results indicate that four well-supported clades of Liliales date back to the Cretaceous ~65 million years ago (mya), Campynemataceae, Melanthiaceae, Smilacaceae + Liliaceae, and Alstroemeriaceae + Luzuriagaceae + Colchicaceae. Aspects of historical biogeography were investigated by dispersal–vicariance analysis. Several dispersal and vicariance events were found to coincide with Late Cretaceous–Early Tertiary changes in continental interconnections. The study contains the first published sequence of Campynemanthe, supporting the Campynemataceae as a monophyletic group.