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Traditionally, the generation and use of biodiversity data and their associated specimen objects have been primarily the purview of individuals and small research groups. While deposition of data and specimens in herbaria and other repositories has long been the norm, throughout most of their history, these resources have been accessible only to a small community of specialists. Through recent concerted efforts, primarily at the level of national and international governmental agencies over the last two decades, the pace of biodiversity data accumulation has accelerated, and a wider array of biodiversity scientists has gained access to this massive accumulation of resources, applying them to an ever‐widening compass of research pursuits. We review how these new resources and increasing access to them are affecting the landscape of biodiversity research in plants today, focusing on new applications across evolution, ecology, and other fields that have been enabled specifically by the availability of these data and the global scope that was previously beyond the reach of individual investigators. We give an overview of recent advances organized along three lines: broad‐scale analyses of distributional data and spatial information, phylogenetic research circumscribing large clades with comprehensive taxon sampling, and data sets derived from improved accessibility of biodiversity literature. We also review synergies between large data resources and more traditional data collection paradigms, describe shortfalls and how to overcome them, and reflect on the future of plant biodiversity analyses in light of increasing linkages between data types and scientists in our field. 

Abstract Astragalus(Fabaceae) is astoundingly diverse in temperate, cold arid regions of Earth, positioning this group as a model clade for investigating the distribution of plant diversity in the face of environmental challenges. Here, we identify the spatial distribution of diversity and endemism inAstragalususing species distribution models for 752 species and a phylogenetic tree comprising 847 species. We integrated these to map centers of species richness (SR) and relative phylogenetic diversity (RPD) and used randomization approaches to investigate centers of endemism. We also used clustering methods to identify phylogenetic regionalizations. We then assembled predictor variables of current climate conditions to test environmental factors predicting these phylogenetic diversity results, especially temperature and precipitation seasonality. We find that SR centers are distributed globally at temperate middle latitudes in arid regions, but the Mediterranean Basin is the most important center of RPD. Endemism centers also occur globally, but Iran represents a key endemic area with a concentration of both paleo‐ and neoendemism. Phylogenetic regionalization recovered an east‐west gradient in Eurasia and an amphitropical disjunction across North and South America; American phyloregions are overall most closely related to east and central Asia. SR, RPD, and lineage turnover are driven mostly by precipitation and seasonality, but endemism is driven primarily by diurnal temperature variation. Endemism and regionalization results point to western Asia and especially Iran as a biogeographic gateway between Europe and Asia. RPD and endemism highlight the importance of temperature and drought stress in determining plant diversity and endemism centers. 

Abstract A hallmark of flowering plants is their ability to invade some of the most extreme and dynamic habitats, including cold and dry biomes, to a far greater extent than other land plants. Recent work has provided insight to the phylogenetic distribution and evolutionary mechanisms which have enabled this success, yet needed is a synthesis of evolutionary perspectives with plant physiological traits, morphology, and genomic diversity. Linking these disparate components will not only lead to better understand the evolutionary parallelism and diversification of plants with these two strategies, but also to provide the framework needed for directing future research. We summarize the primary physiological and structural traits involved in response to cold‐ and drought stress, outline the phylogenetic distribution of these adaptations, and describe the recurring association of these changes with rapid diversification events that occurred in multiple lineages over the past 15 million years. Across these threefold facets of dry‐cold correlation (traits, phylogeny, and time) we stress the contrast between (a) the amazing diversity of solutions flowering plants have developed in the face of extreme environments and (b) a broad correlation between cold and dry adaptations that in some cases may hint at deep common origins. 

PremiseRecent advances in generating large‐scale phylogenies enable broad‐scale estimation of species diversification. These now common approaches typically are characterized by (1) incomplete species coverage without explicit sampling methodologies and/or (2) sparse backbone representation, and usually rely on presumed phylogenetic placements to account for species without molecular data. We used empirical examples to examine the effects of incomplete sampling on diversification estimation and provide constructive suggestions to ecologists and evolutionary biologists based on those results. MethodsWe used a supermatrix for rosids and one well‐sampled subclade (Cucurbitaceae) as empirical case studies. We compared results using these large phylogenies with those based on a previously inferred, smaller supermatrix and on a synthetic tree resource with complete taxonomic coverage. Finally, we simulated random and representative taxon sampling and explored the impact of sampling on three commonly used methods, both parametric (RPANDA and BAMM) and semiparametric (DR). ResultsWe found that the impact of sampling on diversification estimates was idiosyncratic and often strong. Compared to full empirical sampling, representative and random sampling schemes either depressed or inflated speciation rates, depending on methods and sampling schemes. No method was entirely robust to poor sampling, but BAMM was least sensitive to moderate levels of missing taxa. ConclusionsWe suggest caution against uncritical modeling of missing taxa using taxonomic data for poorly sampled trees and in the use of summary backbone trees and other data sets with high representative bias, and we stress the importance of explicit sampling methodologies in macroevolutionary studies.