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Formed by tall flat-topped mountains known as tepuis, the Pantepui is an important center of vascular plant endemism and diversity in South America. In Brazil, the Pantepui is mostly on the border of Venezuela, and an isolated area, Serra do Araca, stands out as the tepui southernmost. In this paper we present a floristic survey of the vascular plants that occur on Serra do Araca, compare the richness to other tepuis, and commented on the conservation of Amazonian 'campos rupestres'. Our dataset includes over 1600 records, either collected by us in three field expeditions, or by other botanists. A checklist with 436 species of vascular plants is provided. Our study also shows that among the 34 tepuis of the Pantepui, Serra do Araca ranks tenth in species richness and has 24 endemic species. Serra do Araca, like other tepuis, houses representatives of ancestral lineages of vascular plants of South America, showing how important tepuis are as cradles of lineages. Despite its importance for Amazonian biodiversity, Serra do Araca is one of the natural reserves in the Amazon with the highest number of requests for mining. Formado por altas montanhas de eumes chapados conhecidos como tepuis, o Pantepui e um importante centro de endemismo e diversidade de plantas vasculares na America do Sul. No Brasil, o Pantepui encontra-se principalmente na fronteira com a Venezuela, e urna area isolada, a Serra do Araca, destaca-se como o mais meridional dos tepuis. Neste trabalho apresentamos um levantamento floristico das plantas vasculares que ocorrem na Serra do Araca, comparamos a riqueza com outros tepuis, e comentamos sobre a conservacao dos campos rupestres amazonicos. Nosso conjunto de dados inclui mais de 1600 registros, coletudos por nos em tres expedicoes de campo, ou por outros botanicos. Urna lista de verificacao com 436 especies de plantas vasculares e fomecida. Nosso estudo tambem mostra que entre os 34 tepuis do Pantepui, a Serra do Araca ocupa a decima posicao em riqueza de especies e possui 24 especies endemicas. A Serra do Araca, como outros tepuis, abriga representantes de linhagens ancestrais de plantas vasculares da America do Sul, mostrando a importancia dos tepuis como bercos de linhagens. Apesar de sua importancia para a biodiversidade amazonica, a Serra do Araca esta em urna das unidades de conservacao estaduais da Amazonia com o maior numero de processos para mineracao. Keywords Neotropical * Biodiversity * Highlands * Campos rupestres, Introduction Amazonia is a tropical forest of great biological importance with high plant species richness compared to other regions of the world (Gentry, 1988; Fiaschi & Pirani, 2009; Antonelli & [...]

The understanding of genetic diversity and evolutionary relationships within the genus Anadenanthera Speg. (Fabaceae) is limited. Brenan's classification recognized four species, but Altschul's classification currently recognizes only two species, each with two varieties. Both classifications were based solely on morphology. We analysed molecular data from 283 specimens using 12 SSRs and 186 specimens using ITS sequence data. The results showed that neither SSR-based genotyping nor ITS-based phylogeny supported Altschul's classification. Instead, they provided evidence of four reproductively isolated taxa and a single clade corresponding to one of Altschul's varieties. Additionally, ecological niche modelling (ENM) investigated the influence of past climate on the geographic distribution of Anadenanthera. The ENM results suggest that the 'varieties' may have occupied different regions of South America with distinct paleoclimates. On the basis of these findings, the authors suggest recognizing four species, as per Brenan's original classification. [ABSTRACT FROM AUTHOR]

Aim: We used a phylogenetic approach to group assemblages of woody plant into major vegetation units in the Atlantic Forest, thus for the first time incorporating information on species evolutionary relationships into a bioregionalization of this critical hotspot. A phylogenetic regionalization will provide a spatially explicit framework for answering many basic and applied questions in biogeography, ecology and conservation. Location: Atlantic Forest. Taxon: Angiosperms Methods: Our data set comprises 614 genera and 116 families, spread over 1,755 assemblages. To place assemblages in a multivariate evolutionary composition space, we used a phylogenetically informed ordination analysis, and to determine what the main phylogenetic groups of assemblages were, we used K‐means clustering based on phylogenetic dissimilarity of assemblages. To quantify how well environmental variables distinguish the phylogenetic groups found, we implemented classification tree approaches. Then, to explore the evolutionary turnover between the phylogenetic groups, we calculated phylogenetic beta diversity. Finally, we determined the lineages that are most strongly associated with individual phylogenetic groups using an indicator analysis for lineages. Results: Our analyses suggest that there are seven principal groups, in terms of evolutionary lineage composition, in the Atlantic Forest. The greatest turnover of phylogenetic lineage composition separates tropical evergreen rain forest and semideciduous assemblages from subtropical and highland assemblages. The mixed subtropical forest showed the lowest phylogenetic compositional similarity values with other groups. Tropical rain forest had the highest number of significant indicator lineages, and the highest values of the indicator statistic for lineages. Main conclusions: We found that the most pronounced evolutionary division separates southern and highland tree assemblages from those occurring under more tropical climates and at lower elevations. Our phylogenetic analyses point to an environmentally driven compositional division, likely based on the regular occurrence of freezing versus non‐freezing temperatures. Precipitation and edaphic regimes that assemblages experience had less definitive effects on their evolutionary lineage composition. [ABSTRACT FROM AUTHOR]