Phylogeny of Australian Gnaphalieae (Asteraceae) Based on Chloroplast and Nuclear Sequences, the trnL Intron, trnL/trnF Intergenic Spacer, matK, and ETS

Abstract The Gnaphalieae are a group of sunflowers that have their greatest diversity in South America, Southern Africa, and Australia. The objective of this study was to reconstruct a phylogeny of the Australian Gnaphalieae using sequence data from the trnL intron, trnL/trnF intergenic spacer, matK, and ETS. Included in this investigation are the Australian genera of the Gnaphalieae from the subtribes Cassiniinae, Gnaphaliinae, Angianthinae, and Loricariinae, and one to four genera from all tribes of the subfamily Asteroideae to serve as outgroups. Results indicate that the subtribes Angianthinae and Cassiniinae are non-monophyletic as currently circumscribed. There is also some evidence to suggest that the genera Asteridea, Craspedia, Hyalosperma, Millotia, and Podolepis are monophyletic, whereas Calocephalus, Gnephosis, Myriocephalus pro parte, Ozothamnus, Siloxerus, Trichanthodium, and Xerochrysum are non-monophyletic. A group of perennial shrubs and alpine cushion plants from southeastern Australia dominates the clade at the base of the Gnaphalieae. The more derived clades contain primarily herbaceous annual taxa, mainly from western Australia. Based on our results, it seems likely that initial colonization and diversification of the Australian Gnaphalieae occurred in the Bassian Floristic region in eastern New South Wales, Victoria, and Tasmania. Following diversification in eastern Australia, concurrent with the increasing aridity over the entire continent during the Miocene, a massive radiation in the Gnaphalieae occurred into the arid zone of South Australia and Western Australia. Communicating Editor: Matt Lavin