title: Recent assembly of the global herbaceous flora: evidence from the paper daisies (Asteraceae: Gnaphalieae).
abstract: The global flora is thought to contain a large proportion of herbs, and understanding the general spatiotemporal processes that shaped the global distribution of these communities is one of the most difficult issues in biogeography. We explored patterns of world-wide biogeography in a species-rich herbaceous group, the paper daisy tribe Gnaphalieae (Asteraceae), based on the hitherto largest taxon sampling, a total of 835 terminal accessions representing 80% of the genera, and encompassing the global geographic range of the tribe, with nuclear internal transcribed spacer (ITS) and external transcribed spacer (ETS) sequences. Biogeographic analyses indicate that Gnaphalieae originated in southern Africa during the Oligocene, followed by repeated migrations into the rest of Africa and the Mediterranean region, with subsequent entries into other continents during various periods starting in the Miocene. Expansions in the late Miocene to Pliocene appear to have been the driving force that shaped the global distribution of the tribe as forests were progressively broken up by the mid-continent aridification and savannas and grasslands expanded into the interior of the major continents. This pattern of recent colonizations may explain the world-wide distribution of many other organisms in open ecosystems and it is highlighted here as an emerging pattern in the evolution of the global flora.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Utilization, College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan, 416000, China.|Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
authors.forename: Ze-Long
authors.initials: ZL
authors.lastname: Nie
authors.affiliation: Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, DC, 20013-7012, USA.
authors.forename: Vicki A
authors.initials: VA
authors.lastname: Funk
authors.affiliation: Key Laboratory of Plant Resources Conservation and Utilization, College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan, 416000, China.|Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Deng
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Botany, National Museum of Natural History, MRC 166, Smithsonian Institution, Washington, DC, 20013-7012, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Wen
mesh_terms: D019659:Asteraceae / Q000502:physiology*; D005843:Geography; D010802:Phylogeny; D013997:Time Factors
keywords: Asteraceae; Compositae; Gnaphalieae; herbaceous flora; late Miocene-Pliocene; open ecosystems; recent expansion