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The figwort family, Scrophulariaceae, comprises c. 2000 species whose evolutionary relationships at the tribal level have proven difficult to resolve, hindering our ability to understand their origin and diversification. We designed a specific probe kit for Scrophulariaceae, targeting 849 nuclear loci and obtaining plastid regions as by-products. We sampled c. 87% of the genera described in the family and use the nuclear dataset to estimate evolutionary relationships, timing of diversification, and biogeographic patterns. Ten tribes, including two new tribes, Androyeae and Camptolomeae, are supported, and the phylogenetic positions of Androya, Camptoloma, and Phygelius are unveiled. Our study reveals a major diversification at c. 60 million yr ago in some Gondwanan landmasses, where two different lineages diversified, one of which gave rise to nearly 81% of extant species. A Southern African origin is estimated for most modern-day tribes, with two exceptions, the American Leucophylleae, and the mainly Australian Myoporeae. The rapid mid-Eocene diversification is aligned with geographic expansion within southern Africa in most tribes, followed by range expansion to tropical Africa and multiple dispersals out of Africa. Our robust phylogeny provides a framework for future studies aimed at understanding the role of macroevolutionary patterns and processes that generated Scrophulariaceae diversity., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)

This review uses proxies of past temperature and atmospheric CO(2) composition based on fossil leaves to illustrate the uncertainties in biologically based proxies of past environments. Most leaf-based proxies are geographically local or genetically restricted and therefore can be confounded by evolution, extinction, changes in local environment or immigration of species. Stomatal frequency proxies illustrate how genetically restricted proxies can be particularly vulnerable to evolutionary change. High predictive power in the modern world resulting from the use of a very narrow calibration cannot be confidently extrapolated into the past (the Ginkgo paradox). Many foliar physiognomic proxies of climate are geographically local and use traits that are more or less fixed for individual species. Such proxies can therefore be confounded by floristic turnover and biome shifts in the region of calibration. Uncertainty in proxies tends to be greater for more ancient fossils. I present a set of questions that should be considered before using a proxy. Good proxies should be relatively protected from environmental and genetic change, particularly through having high information content and being founded on biomechanical or biochemical principles. Some current and potential developments are discussed, including those that involve more mechanistically sound proxies and better use of multivariate approaches., (© 2011 The Author. New Phytologist © 2011 New Phytologist Trust.)

•  Leaf morphology varies predictably with altitude, and leaf morphological features have been used to estimate average temperatures from fossil leaves. The altitude-leaf morphology relationship is confounded by the two processes of acclimation and adaptation, which reflect environmental and genetic influences, respectively. •  Here we describe the relationship between altitude and leaf morphology for Southern beech, Nothofagus cunninghamii (Hook.) Oerst.. Cuttings from several trees from each of four altitudes were grown in a common glasshouse experiment, and leaf morphology related to both genotype and altitude of origin. •  Genotype had a significant impact on leaf morphology, but in the field there was also a significant, overriding effect of altitude. This altitude effect disappeared in glasshouse-grown plants for all morphological variables other than leaf thickness and specific leaf area. •  These results show that, while leaf length, width and area are partially controlled by genetic factors, these variables are plastic and respond to environmental influences associated with a particular altitude. Thus altitudinal trends in leaf size in N. cunninghamii are unlikely to be the result of adaptation.