Format: ORAL

Sebastian Gebauer1, Pedro Jimnez-Mejas2, Mohammad Amini Rad3, Carmen Bentez-Bentez4, Asuncin Cano5, Kyong-Sook Chung6, Bernhard W. Dickor7, Marcial Escudero4, Adrien Favre8, Andrew L. Hipp9,10, Takuji Hoshino11, Xiao-Feng Jin12, Sangtae Kim13, Chun-Kuei Liao14, Santiago Martn-Bravo2, Tomomi Masaki15, Ana Morales Alonso16, Mnica Mguez4, Georg Miehe17, Anton A. Reznicek18, Eric H. Roalson19, Julian R. Starr20, Irina Shekhovtsova21, Polina A. Volkova22, Marcia J. Waterway23, Martin Rser1 Matthias H. Hoffmann1

1 Department of Systematic Botany, Martin Luther University Halle-Wittenberg, Geobotany and Botanical Garden, Halle (Saale), Germany, 2 Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain, 3 Research Institute of Forests and Rangelands, Agricultural Research, Education, and Extension Organization (AREEO), Tehran, Iran, 4 Department of Plant Biology and Ecology, Universidad de Sevilla, Seville, Spain, 5 Natural History Museum and Biological Sciences Faculty, Universidad Nacional Mayor de San Marcos, Lima, Peru, 6 Department of Medicinal Plant Science, Jungwon University, Goesan, South Korea, 7 Department of Vascular Plants, Botanische Staatssammlung München & Systematic Botany and Mycology, University of München, München, Germany, 8 Parc naturel régional de la Vallée de Trient, Salvan, Switzerland, 9 The Morton Arboretum, Lisle, USA, 10 The Field Museum, Chicago, USA, 11 Department of Biosphere-Geosphere Science, Faculty of Biosphere-Geosphere Science, Okayama University of Science, Okayama, Japan, 12 Zhejiang Provincial Key Laboratory of Forest Aromatic Plants-based Healthcare Functions and School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, Zhejiang, China, 13 Department of Biology, Sungshin University, Seoul, South Korea, 14 Lioukuei Research Center, Taiwan Forestry Research Institute, Kaohsiung County, Taiwan, 15 Nature Fieldwork Center, Okayama University of Science, Okayama, Japan, 16 Biodiversity and Conservation Area, Department of Biology and Geology, Physics and Inorganic Chemistry, Universidad Rey Juan Carlos, Madrid, Spain, 17 Department of Geography, Vegetation Geography, Philipps-Universität Marburg, Marburg, Germany, 18 University of Michigan Herbarium, Ann Abor, USA, 19 School of Biological Sciences, Washington State University, Pullman, USA, 20 Department of Biology, University of Ottawa, Ottawa, Canada, 21 Central Siberian Botanical Garden SB RAS, Novosibirsk, Russia, 22 Papanin Institute for Biology of Inland Waters RAS, Borok, Russia, 23 Plant Science Department, McGill University, Quebec, Canada

The mainly arctic-alpineCarexsect.Racemosae(60 spp.) constitutes one of the larger, yet taxonomically most challenging groups within the megadiverse genusCarex. Previous molecular studies have been limited by incomplete sampling and have failed to disentangle the taxonomic delimitation and phylogenetic placement of several controversial, doubtful, or rare species. We achieved a more or less complete species sampling thanks to a global collaborative effort, including field campaigns and herbarium work as well as ongoing taxonomic revisions in Eurasia and the Neotropics, Divergence-time estimation and multispecies coalescent (MSC) analyses were conducted on a multi-accession Sanger-sequencing dataset (i.e., multiple samples per species) using nuclear (ITS, ETS) and plastid (rps16,trnKmatK,trnLtrnF) DNA regions (c. 6,000 bp). Biogeographic analyses suggest a Late Miocene (c. 10 Myr) origin within the forest and mountain-steppe belts of the Northern Hemisphere, followed by several, partly trans-continental range expansions, mainly during the early diversification process (105 Myr). A trans-Cordilleran disjunction is also evident. Overall patterns highlight the importance of Central Asia and Western North America for the groups diversification. Obtained clades are more congruent with biogeographic rather than by morphological patterns. Diversification rate analyses showed an unexpected, continuous and uniform slowdown in diversification rates across all major clades, suggesting niche conservatism coupled with niche filling. Finally, several taxonomic and nomenclatural changes are suggested, i.e. some regional taxa previously placed in synonymy of other widespread species require revalidation (e.g.,C. apodostachya) or remain orphan species with no clear assignment to any specific clade (e.g.,C. serreana). In conclusion, our collaborative study provides fundamental insights into the evolutionary dynamics of a significant high mountain plant group and lays the groundwork for a comprehensive global revision ofCarexsect.Racemosae.