The relative importance of local ecological and larger-scale historical processes in causing differences in species richness across the globe remains keenly debated. To gain insight into these questions, we investigated the assembly of plant diversity in the Cerrado in South America, the world's most species-rich tropical savanna. Time-calibrated phylogenies suggest that Cerrado lineages started to diversify less than 10 Mya, with most lineages diversifying at 4 Mya or less, coinciding with the rise to dominance of flammable C4 grasses and expansion of the savanna biome worldwide. These plant phylogenies show that Cerrado lineages are strongly associated with adaptations to fire and have sister groups in largely fire-free nearby wet forest, seasonally dry forest, subtropical grassland, or wetland vegetation. These findings imply that the Cerrado formed in situ via recent and frequent adaptive shifts to resist fire, rather than via dispersal of lineages already adapted to fire. The location of the Cerrado surrounded by a diverse array of species-rich biomes, and the apparently modest adaptive barrier posed by fire, are likely to have contributed to its striking species richness. These findings add to growing evidence that the origins and historical assembly of species-rich biomes have been idiosyncratic, driven in large part by unique features of regional-and continental-scale geohistory and that different historical processes can lead to similar levels of modern species richness.

The classification of the legume family proposed here addresses the long‐known non‐monophyly of the traditionally recognised subfamily Caesalpinioideae, by recognising six robustly supported monophyletic subfamilies. This new classification uses as its framework the most comprehensive phylogenetic analyses of legumes to date, based on plastid matK gene sequences, and including near‐complete sampling of genera (698 of the currently recognised 765 genera) and ca. 20% (3696) of known species. The matK gene region has been the most widely sequenced across the legumes, and in most legume lineages, this gene region is sufficiently variable to yield well‐supported clades. This analysis resolves the same major clades as in other phylogenies of whole plastid and nuclear gene sets (with much sparser taxon sampling). Our analysis improves upon previous studies that have used large phylogenies of the Leguminosae for addressing evolutionary questions, because it maximises generic sampling and provides a phylogenetic tree that is based on a fully curated set of sequences that are vouchered and taxonomically validated. The phylogenetic trees obtained and the underlying data are available to browse and download, facilitating subsequent analyses that require evolutionary trees. Here we propose a new community‐endorsed classification of the family that reflects the phylogenetic structure that is consistently resolved and recognises six subfamilies in Leguminosae: a recircumscribed Caesalpinioideae DC., Cercidoideae Legume Phylogeny Working Group (stat. nov.), Detarioideae Burmeist., Dialioideae Legume Phylogeny Working Group (stat. nov.), Duparquetioideae Legume Phylogeny Working Group (stat. nov.), and Papilionoideae DC. The traditionally recognised subfamily Mimosoideae is a distinct clade nested within the recircumscribed Caesalpinioideae and is referred to informally as the mimosoid clade pending a forthcoming formal tribal and/or clade‐based classification of the new Caesalpinioideae. We provide a key for subfamily identification, descriptions with diagnostic charactertistics for the subfamilies, figures illustrating their floral and fruit diversity, and lists of genera by subfamily. This new classification of Leguminosae represents a consensus view of the international legume systematics community; it invokes both compromise and practicality of use.

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With contributions by: Abreu, Maria C.; Acevedo-Rodríguez, Pedro; Agra, Maria F.; Almeida Jr., Eduardo B.; Almeida, Gracineide S.S.; Almeida, Rafael F.; Alves, Flávio M.; Alves, Marccus; Alves-Araujo, Anderson; Amaral, Maria C.E.; Amorim, André M.; Amorim, Bruno; Andrade, Ivanilza M.; Andreata, Regina H.P.; Andrino, Caroline O.; Anunciação, Elisete A.; Aona, Lidyanne Y.S.; Aranguren, Yani; Aranha Filho, João L.M.; Araújo, Andrea O.; Araújo, Ariclenes A.M.; Araújo, Diogo; Arbo, María M.; Assis, Leandro; Assis, Marta C.; Assunção, Vivian A.; Athiê-Souza, Sarah M.; Azevedo, Cecilia O.; Baitello, João B.; Barberena, Felipe F.V.A.; Barbosa, Maria R.V.; Barros, Fábio; Barros, Lucas A.V.; Barros, Michel J.F.; Baumgratz, José F.A.; Bernacci, Luis C.; Berry, Paul E.; Bigio, Narcísio C.; Biral, Leonardo; Bittrich, Volker; Borges, Rafael A.X.; Bortoluzzi, Roseli L.C.; Bove, Cláudia P.; Bovini, Massimo G.; Braga, João M.A.; Braz, Denise M.; Bringel Jr., João B.A.; Bruniera, Carla P.; Buturi, Camila V.; Cabral, Elza; Cabral, Fernanda N.; Caddah, Mayara K.; Caires, Claudenir S.; Calazans, Luana S.B.; Calió, Maria F.; Camargo, Rodrigo A.; Campbell, Lisa; Canto-Dorow, Thais S.; Carauta, Jorge P.P. †; Cardiel, José M.; Cardoso, Domingos B.O.S.; Cardoso, Leandro J.T.; Carneiro, Camila R.; Carneiro, Cláudia E.; Carneiro-Torres, Daniela S.; Carrijo, Tatiana T.; Caruzo, Maria B.R.; Carvalho, Maria L.S.; Carvalho-Silva, Micheline; Castello, Ana C.D.; Cavalheiro, Larissa; Cervi, Armando C. †; Chacon, Roberta G.; Chautems, Alain; Chiavegatto, Berenice; Chukr, Nádia S.; Coelho, Alexa A.O.P.; Coelho, Marcus A.N.; Coelho, Rubens L.G.; Cordeiro, Inês; Cordula, Elizabeth; Cornejo, Xavier; Côrtes, Ana L.A.; Costa, Andrea F.; Costa, Fabiane N.; Costa, Jorge A.S.; Costa, Leila C.; Costa-e-Silva, Maria B.; Costa-Lima, James L.; Cota, Maria R.C.; Couto, Ricardo S.; Daly, Douglas C.; De Stefano, Rodrigo D.; De Toni, Karen; Dematteis, Massimiliano; Dettke, Greta A.; Di Maio, Fernando R.; Dórea, Marcos C.; Duarte, Marília C.; Dutilh, Julie H.A.; Dutra, Valquíria F.; Echternacht, Lívia; Eggers, Lilian; Esteves, Gerleni; Ezcurra, Cecilia; Falcão Junior, Marcus J.A.; Feres, Fabíola; Fernandes, José M.; Ferreira, D.M.C.; Ferreira, Fabrício M.; Ferreira, Gabriel E.; Ferreira, Priscila P.A.; Ferreira, Silvana C.; Ferrucci, Maria S.; Fiaschi, Pedro; Filgueiras, Tarciso S.; Firens, Marcela; Flores, Andreia S.; Forero, Enrique; Forster, Wellington; Fortuna-Perez, Ana P.; Fortunato, Reneé H.; Fraga, Cláudio N.; França, Flávio; Francener, Augusto; Freitas, Joelcio; Freitas, Maria F.; Fritsch, Peter W.; Furtado, Samyra G.; Gaglioti, André L.; Garcia, Flávia C.P.; Germano Filho, Pedro; Giacomin, Leandro; Gil, André S.B.; Giulietti, Ana M.; Godoy, Silvana A.P. ; Goldenberg, Renato; Gomes da Costa, Géssica A.; Gomes, Mário; Gomes-Klein, Vera L.; Gonçalves, Eduardo Gomes; Graham, Shirley; Groppo, Milton; Guedes. Juliana S.; Guimarães, Leonardo R.S.; Guimarães, Paulo J.F.; Guimarães, Elsie F.; Gutierrez, Raul; Harley, Raymond; Hassemer, Gus...

Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.Amazonia | floristics | rain forests | seed plants | species diversity

The field of molecular plant phylogenetics has had tremendous impacts on botanical studies and taxonomic classification, macroevolution and biogeography, ever since the pioneering studies of Chase et al. (1993) based on DNA sequence data. While those early studies used just a single locus, the plastid gene rbcL, modern studies often employ hundreds to several thousands of genes to infer phylogenetic relationships (e.g.,

Although based on a single plastid region, our results establish a preliminary phylogenetic framework for Mimosa that can be used to infer patterns of morphological evolution and relationships and which provides pointers toward a revised infrageneric classification.

The well-resolved phylogeny of the earliest-branching papilionoids generated in this study will greatly facilitate the efforts to redefine and stabilize the classification of this legume subfamily. Many key floral traits did not often predict phylogenetic relationships, so comparative studies on floral evolution and plant-animal interactions, for example, should also benefit from this study.