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Geographical variation in species richness in plant groups is determined by the interplay between historical, evolutionary, and ecological processes. However, the processes underlying the striking disparity in species richness between Asia and the Americas remain poorly understood. Here, we synthesize global phylogenetic and macroecological data on the diversification of Smilacaceae, deciphering potential drivers underlying the species diversity pattern biased toward Asia. We compiled global distributions of all Smilacaceae species, and reconstructed the biogeographic history and niche evolution using a new time‐calibrated phylogeny (eight genes, 135 species). Integrating these data sets, we estimated evolutionary histories and diversification rates for each region, and tested correlations among species diversification, niche evolution, and niche divergence. Smilacaceae probably originated during the Late Cretaceous/Early Palaeocene and began to diversify in middle to low latitudes in Central America and Eurasia during the Late Eocene. Both the Old and New World clades exhibited a steady, albeit slight, increase of species diversification from the Late Eocene to Early Miocene. However, the Old World clade experienced an abrupt increase in net diversification during the Late Miocene. Our findings also revealed that species diversification rates were positively correlated with ecological niche evolution and niche divergence. Niche shifts and climatic niche evolution since the Middle Miocene played crucial roles in species diversification dynamics within Smilacaceae. The high plant richness in Asia may be explained by greater diversification in this region, potentially promoted by heterogeneous environments. [ABSTRACT FROM AUTHOR]

Premise of the study: Although several microsatellite markers of Smilax aspera (Smilacaceae) have been reported in a previous study, due to universality issues in cross‐population amplification, we have newly developed microsatellite markers for S. aspera based on transcriptome data to further investigate gene flow and genetic structure of its circum‐Mediterranean, East African, and South Asian populations. Methods and Results: A total of 4854 simple sequence repeat (SSR) primer pairs were designed from 99,193 contigs acquired from public transcriptome data of S. bona‐nox. Forty‐six microsatellite loci were selected for further genotyping in 12 S. aspera populations. The number of alleles varied from three to 28, and 93.5% of the developed microsatellite markers could be cross‐amplified in least one of three congeneric Smilax species. Conclusions: The SSR markers developed in this study will facilitate further studies on genetic diversity and phylogeographic patterns of S. aspera in intercontinental geographical scales. [ABSTRACT FROM AUTHOR]

Fothergilla (Hamamelidaceae) consists of Fothergilla gardenii (4 x) from the coastal plains of the southeastern USA, F. major (6 x) from the piedmont and mountains of the same region, and a few allopatric diploid populations of unknown taxonomic status. The objective of this study was to explore the relationships of the polyploid species with the diploid plants. Genotyping by sequencing (GBS) was applied to generate genome-wide molecular markers for phylogenetic and genetic structure analyses of 36 accessions of Fothergilla. Sanger sequencing of three plastid and one nuclear regions provided data for comparison with GBS-based results. Phylogenetic outcomes were compared using data from different sequencing runs and different software workflows. The different data sets showed substantial differences in inferred phylogenies, but all supported a genetically distinct 6 x F. major and two lineages of the diploid populations closely associated with the 4 x F. gardenii. We hypothesize that the 4 x F. gardenii originated through hybridization between the Gulf coastal 2 x and an extinct (or undiscovered) 2 x lineage, followed by backcrosses to the Atlantic coastal 2 x before chromosome doubling, and the 6 x F. major also originated from the 'extinct' 2 x lineage. Alternative scenarios are possible but are not as well supported. The origins and divergence of the polyploid species likely occurred during the Pleistocene cycles of glaciation, although fossil evidence indicates the genus might have existed for a much longer time with a wider past distribution. Our study demonstrates the power of combining GBS data with Sanger sequencing in reconstructing the evolutionary network of polyploid lineages. [ABSTRACT FROM AUTHOR]

Tethyan plant disjunctions, including Mediterranean-African-Asian disjunctions, are thought to be vicariant, but their temporal origin and underlying causes remain largely unknown. To address this issue, we reconstructed the evolutionary history of Smilax aspera, a hypothesized component of the European Tertiary laurel forest flora., Thirty-eight populations and herbarium specimens representing 57 locations across the species range were sequenced at seven plastid regions and the nuclear ribosomal internal transcribed spacer region. Time-calibrated phylogenetic and phylogeographic inferences were used to trace ancestral areas and biogeographical events., The deep intraspecific split between Mediterranean and African-Asian lineages is attributable to range fragmentation of a southern Tethyan ancestor, as colder and more arid climates developed shortly after the mid-Miocene. In the Mediterranean, climate-induced vicariance has shaped regional population structure since the Late Miocene/Early Pliocene. At around the same time, East African and South Asian lineages split by vicariance, with one shared haplotype reflecting long-distance dispersal., Our results support the idea that geographic range formation and divergence of Tertiary relict species are more or less gradual (mostly vicariant) processes over long time spans, rather than point events in history. They also highlight the importance of the Mediterranean Basin as a centre of intraspecific divergence for Tertiary relict plants. [ABSTRACT FROM AUTHOR]