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Abstract The Anacardiaceae are a characteristic angiosperm family of the Neotropics where they comprise ~32 genera and 200 species (~80 genera and 800 species globally). Among Neotropical Anacardiaceae genera, Schinus has the greatest species richness with 42 species distributed from tropical latitudes of Brazil and Peru south to the temperate steppe, matorral, and Valdivian temperate forest communities of Patagonia. Previous studies have found some anatomical and morphological leaf traits (e.g. simple vs. compound leaf organization) useful in characterizing lineages within Schinus, but also document traits that are homoplastic within the genus (e.g. stomatal distribution) and convergent among Schinus and its close relatives Lithrea and Mauria (e.g. mesophyll arrangement). Here, we present a survey of leaf cuticular traits in 53 species of Schinus and its closest relatives Lithrea, Mauria, and Euroschinus based on characters observed with scanning electron and optical light microscopy. We use ordinated Bray–Curtis distances based on 18 characters and 2D nonmetric multidimensional scaling to show that cuticular morphology resolves the three most diverse genera, Euroschinus, Mauria, and Schinus, but does not resolve intrageneric sections of Schinus. We propose that a distinctive acuminate gland type occurring only within Euroschinus may constitute a potential synapomorphy for this genus. Within Schinus, we find inconsistency in stomatal distribution among specimens of a single species, among species of a single section, and between sections of the genus, and suggest that current evidence is insufficient to implicate either phenotypic plasticity or homoplasy as the causative mechanism of this variation. 

Abstract Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods^1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome^3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins^5–7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes⁸. This 15-fold increase in genus-level sampling relative to comparable nuclear studies⁹provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.