Phylogeny, biogeography, and morphological evolution among and within the Neotropical and Asian clades of Schefflera (Araliaceae)

Schefflera is the largest and most complex genus of Araliaceae, with ~600 described species (and many additional species awaiting formal description), but recent studies indicate that it is polyphyletic, forming five geographically centered clades spread across the major lineages of the family. Significant progress has been made in revising the three smallest clades, but the two largest groups, centered in Asia and the Neotropics, remain poorly understood. To advance our knowledge of these groups, a taxon set of 211 Schefflera samples and 38 samples representing other genera of Araliaceae (including all genera of the “Asian Palmate clade”) was assembled, from which sequences were obtained for six DNA spacer regions, including two nuclear (ITS, ETS) and four plastid markers (rpl32-trnL, trnF-rpl32, trnK-rpl16, psbA-trnH). Results were compared to an informal system of classification based on morphology. They confirm the monophyly of both the Asian and Neotropical groups, and their inclus...