The pantropical genus Begonia is the sixth-largest genus of flowering plants, including 1870 species. The sections of Begonia are used frequently as analogues to genera in other families but, despite their taxonomic utility, few of the current sections have been examined in the light of molecular phylogenetic analyses. We present herein the largest, most representative phylogeny of Begonia published to date and a subsequent provisional sectional classification of the genus. We utilised three plastid markers for 574 species and 809 accessions of Begonia and used Hillebrandia as an outgroup to produce a dated phylogeny. The relationships between some species and sections are poorly resolved, but many sections and deeper nodes receive strong support. We recognise 70 sections of Begonia including 5 new sections: Astrothrix, Ephemera, Jackia, Kollmannia, and Stellandrae; 4 sections are reinstated from synonymy: Australes, Exalabegonia, Latistigma and Pereira; and 5 sections are newly synonymised. The new sectional classification is discussed with reference to identifying characters and previous classifications.
Aim The complex palaeogeography of the Malesian archipelago, characterized by the evolution of an ever-changing mosaic of terrestrial and marine areas throughout the Cenozoic, provides the geographic backdrop for the remarkable diversification of Malesian Begonia (> 450 species). This study aimed to investigate the origin of Malesian Begonia, the directionality of dispersal events within the Malesian archipelago and the impact of ancient water gaps on colonization patterns, and to identify drivers of diversification.Location Asia, Southeast Asia, Malesia.Methods Plastid DNA sequence data of representatives of all families of the Cucurbitales and Fagales (matK, rbcL, trnL intron, trnL-F spacer, 4076 aligned positions, 92 taxa) and a sample of all major Asian Begonia sections (ndhA intron, ndhF-rpl32 spacer, rpl32-trnL spacer, 4059 aligned positions, 112 taxa) were analysed under an uncorrelated-rates relaxed molecular clock model to estimate the age of the Begonia crown group divergence and divergence ages within Asian Begonia. Ancestral areas were reconstructed using a likelihood approach implementing a dispersal-extinction-cladogenesis model, and with a Bayesian approach to dispersal-vicariance analysis.
Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.
Nine new species of Begonia (Begoniaceae), Begonia comestibilis D.C.Thomas & Ardi, B. insueta D.C.Thomas & Ardi, B. lasioura D.C.Thomas & Ardi, B. nobmanniae D.C.Thomas & Ardi, B. prionota D.C.Thomas & Ardi, B. rantemarioensis D.C.Thomas & Ardi, B. sanguineopilosa D.C.Thomas & Ardi, B. torajana D.C.Thomas & Ardi and B. vermeulenii D.C.Thomas, are described from South and West Sulawesi, Indonesia. All belong to Begonia section Petermannia. Proposed conservation categories for these species are Vulnerable (VU) for Begonia comestibilis, B. nobmanniae, B. prionota, B. sanguineopilosa and B. vermeulenii; Least Concern (LC) for B. lasioura, B. rantemarioensis and B. torajana; and Data Deficient (DD) for B. insueta. An identification key to Begonia in South and West Sulawesi (Sulawesi Selatan and Sulawesi Barat) is provided.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.