Mountains are among the most biodiverse areas on the globe. In young mountain ranges, exceptional plant species richness is often associated with recent and rapid radiations linked to the mountain uplift itself. In ancient mountains, however, orogeny vastly precedes the evolution of vascular plants, so species richness has been explained by species accumulation during long periods of low extinction rates. Here we evaluate these assumptions by analysing plant diversification dynamics in the campo rupestre , an ecosystem associated with pre-Cambrian mountaintops and highlands of eastern South America, areas where plant species richness and endemism are among the highest in the world. Analyses of 15 angiosperm clades show that radiations of endemics exhibit fastest rates of diversification during the last 5 Myr, a climatically unstable period. However, results from ancestral range estimations using different models disagree on the age of the earliest in situ speciation events and point to a complex floristic assembly. There is a general trend for higher diversification rates associated with these areas, but endemism may also increase or reduce extinction rates, depending on the group. Montane habitats, regardless of their geological age, may lead to boosts in speciation rates by accelerating population isolation in archipelago-like systems, circumstances that can also result in higher extinction rates and fast species turnover, misleading the age estimates of endemic lineages.

BackgroundIn the past three decades, several studies have predominantly relied on a small sample of the plastome to infer deep phylogenetic relationships in the species-rich Melastomataceae. Here, we report the first full plastid sequences of this family, compare general features of the sampled plastomes to other sequenced Myrtales, and survey the plastomes for highly informative regions for phylogenetics.MethodsGenome skimming was performed for 16 species spread across the Melastomataceae. Plastomes were assembled, annotated and compared to eight sequenced plastids in the Myrtales. Phylogenetic inference was performed using Maximum Likelihood on six different data sets, where putative biases were taken into account. Summary statistics were generated for all introns and intergenic spacers with suitable size for polymerase chain reaction (PCR) amplification and used to rank the markers by phylogenetic information.ResultsThe majority of the plastomes sampled are conserved in gene content and order, as well as in sequence length and GC content within plastid regions and sequence classes. Departures include the putative presence of rps16 and rpl2 pseudogenes in some plastomes. Phylogenetic analyses of the majority of the schemes analyzed resulted in the same topology with high values of bootstrap support. Although there is still uncertainty in some relationships, in the highest supported topologies only two nodes received bootstrap values lower than 95%.DiscussionMelastomataceae plastomes are no exception for the general patterns observed in the genomic structure of land plant chloroplasts, being highly conserved and structurally similar to most other Myrtales. Despite the fact that the full plastome phylogeny shares most of the clades with the previously widely used and reduced data set, some changes are still observed and bootstrap support is higher. The plastome data set presented here is a step towards phylogenomic analyses in the Melastomataceae and will be a useful resource for future studies.

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Premise Putatively single‐copy nuclear (SCN) loci, which are identified using genomic resources of closely related species, are ideal for phylogenomic inference. However, suitable genomic resources are not available for many clades, including Melastomataceae. We introduce a versatile approach to identify SCN loci for clades with few genomic resources and use it to develop probes for target enrichment in the distantly related Memecylon and Tibouchina (Melastomataceae). Methods We present a two‐tiered pipeline. First, we identified putatively SCN loci using MarkerMiner and transcriptomes from distantly related species in Melastomataceae. Published loci and genes of functional significance were then added (384 total loci). Second, using HybPiper, we retrieved 689 homologous template sequences for these loci using genome‐skimming data from within the focal clades. Results We sequenced 193 loci common to Memecylon and Tibouchina. Probes designed from 56 template sequences successfully targeted sequences in both clades. Probes designed from genome‐skimming data within a focal clade were more successful than probes designed from other sources. Discussion Our pipeline successfully identified and targeted SCN loci in Memecylon and Tibouchina, enabling phylogenomic studies in both clades and potentially across Melastomataceae. This pipeline could be easily applied to other clades with few genomic resources.

Plastome Evolution in Opuntioideae (Cactaceae) with primers designed for continued evolutionary studies across Cactaceae. These results bring new insights into the evolution of plastomes in cacti, suggesting that further analyses should be carried out to address how ecological drivers, physiological constraints and morphological traits of cacti may be related with the common rearrangements in plastomes that have been reported across the family.

The genus Pleiochiton, as traditionally circumscribed, comprises nine species of epiphytic shrubs endemic to the Atlantic Rain Forest in eastern Brazil. We present here the results of the phylogenetic analysis of four plastid DNA regions (accD-psa1, psbK-psbL, ndhF, atpF-atpH), another of nuclear DNA (internal transcribed spacer, ITS) and a third with morphological characters. The datasets were analysed separately and also combined (all plastid regions, ITS + plastid, morphology and all molecular + morphology). These analyses were made in order to access the phylogenetic relationships between the species of Pleiochiton and related species in other genera, and to establish the circumscription of the genus and understand character evolution within the clade. The genus is monophyletic and supported by high jackknife values in all analyses, which showed some resolution if Clidemia blepharodes and C. parasitica were included. The clade comprises the epiphytic species with succulent roots. Most species have a hypodermis with more than one layer of cells, and also glandular trichomes, bracteoles 2.1-5.0 mm long, calyx teeth and hypanthium ratio ranging from 0.4 to 1.2, oval-oblong petals longer than 4.3 mm, and oval-oblong seeds, with a transition zone between the raphal region and testa made up of differentiated cells.

-(Floristic, structure and phytogeography of vegetation in a transition region between Araucaria and Montane Atlantic Forests, Piraquara, Paraná, Brazil). In this work we characterize the composition and the structure of the arboreal vegetation and analyze the geographic distribution of the species sampled in a transitional region between the Araucaria Forest and Montane Atlantic Rainforest in Piraquara, Paraná. We sampled 617 individuals, distributed in 31 families and 85 species. The most diverse families were Myrtaceae (22 species), Lauraceae (11), Rubiaceae (6) and Aquifoliaceae (4). The most important species in the structural analyses were Alsophila setosa, Ocotea catharinensis, Cyathea phalerata, Cryptocarya aschersoniana and Cordiera concolor. It was possible to evidence that the Montane Atlantic Rainforest in the state of Paraná presents differentiated floristic composition, and the existence of a transitional gradient between Araucaria and Montane Atlantic in the Paraná's Atlantic range. Both composition and structure data indicate that the analyzed community is in advanced succession state and deserves rigorous conservation. Key words: Araucaria Forest, Montane Atlantic Forest, Phytogeography, Phytosociology RESUMO -(Análise florística, estrutural e fitogeográfica da vegetação em região de transição entre as Florestas Ombrófilas Mista e Densa Montana, Piraquara, Paraná, Brasil). Os objetivos deste trabalho foram caracterizar a composição e a estrutura da vegetação arbórea e analisar a distribuição geográfica das espécies amostradas em uma região de transição entre as Florestas Ombrófilas Mista e Densa Montana em Piraquara, Paraná. Foram amostrados 617 indivíduos, distribuídos em 31 famílias e 85 espécies. As famílias mais diversas foram Myrtaceae (22 espécies), Lauraceae (11), Rubiaceae (6) e Aquifoliaceae (4). Estruturalmente, as espécies mais importantes foram Alsophila setosa, Ocotea catharinensis, Cyathea phalerata, Cryptocarya aschersoniana e Cordiera concolor. Foi possível constatar que a Floresta Ombrófila Densa Montana no estado do Paraná apresenta composição florística diferenciada e ainda, a existência de um gradiente transicional entre as floras de Floresta Ombrófila Mista e Densa Submontana na Serra do Mar paranaense. Tanto os dados de composição como os estruturais indicam que a comunidade analisada se apresenta em estágio avançado de sucessão e merece rigorosa conservação.

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