Format: ORAL

Dbora Zuanny1, Domingos Cardoso1,2, Tiina Srkinen3, Sandra Knapp4, Peter W. Moonlight5

1 Instituto de Biologia, Universidade Federal da Bahia (UFBA), Salvador, Bahia, Brazil 2 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (JBRJ), Rio de Janeiro, Brazil 3 Royal Botanic Garden Edinburgh, Scotland, UK 4 Natural History Museum, London, England, UK 5 Botany, School of Natural Sciences, Trinity College Dublin, Ireland

Big plant genera are often considered the final frontier of plant systematics. Their size means that they are difficult to study in their entirety and as a consequence the taxonomy, systematics, evolutionary history, and ecology of these genera are poorly known. It is now 20 years since the last review of the history and concepts of big plant genera, when 57 such genera were recognized. There has been a proliferation in plant bioinformatics and taxonomic databases over the past 20 years, including the World Flora Online and Plants of the World Online. Here we review the current number, size, and geographic distribution of big plant genera based on the current data. We recognize 87 big plant genera, an increase of 30 genera, that collectively include 25% of all plant species. Of these genera, 28-29 are considered megadiverse with 1000 species each and account for 13% of all plant species. We discuss, with examples, the mechanisms behind the changes in the number and size of big and megadiverse genera since 2004. We compare the distribution of species in big plant genera to the distribution of flowering plants as a whole to demonstrate that big genera have diversified through the temperate and tropical regions of the world but are over-represented in temperate regions.