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PREMISE OF THE STUDY: Fossilized seeds similar to Cissus (Vitaceae) have been recognized from the Miocene of Kenya, though some were previously assigned to the Menispermaceae. We undertook a comparative survey of extant African Cissus seeds to identify the fossils and consider their implications for the evolution and biogeography of Cissus and for African early Miocene paleoenvironments. METHODS: Micro-computed tomography (pCT) and synchrotron-based X-ray tomographic microscopy (SRXTM) were used to study seed morphology and anatomy. Virtual taphonomy, using SRXTM data sets, produced digital fossils to elucidate seed taphonomy. Phylogenetic relationships within Cissus were reconstructed using existing and newly produced DNA sequences for African species. Paleobiology and paleoecology were inferred from African nearest living relatives. KEY RESULTS: The fossils were assigned tofour new Cissus species, related tofour modern clades. The fossil plants were interpreted as climbers inhabiting a mosaic of riverine woodland and forest to more open habitats. Virtual taphonomy explained how complex mineral infill processes concealed key seed features, causing the previous taxonomic misidentification. Newly sampled African species, with seeds most similar to the fossils, belong tofour clades within core Cissus, two of which are early diverging. CONCLUSIONS: Virtual taphonomy, combined with X-ray imaging, has enabled recognition of the first fossil Cissus and Vitaceae from Africa. Early-divergent members of the core Cissus clade were present in Africa by at least the early Miocene, with an African origin suggested for the Cissus sciophila clade. The fossils provide supporting evidence for mosaic paleoenvironments inhabited by early Miocene hominoids. [ABSTRACT FROM AUTHOR]

Premise of research. Propagule dispersal allows for the movement of plants across landscapes, establishing spatial structure and driving geographic range expansions and shifts. Because this movement is critical to the survival of plant populations and species, particularly during times of rapid and large-scale climate change, dispersal patterns and potential are important to consider when both exploring the past and predicting the future. Methodology. This study analyzes wind dispersal patterns in the genus Carpinus using field collections of dispersed fruits, sampled with high spatial resolution over two complete dispersal seasons and in multiple directions away from parent plants. These detailed collections, with direction-specific information, were then used in an observation-based migration simulation developed to identify the impact of dispersal patterns on population movement. Pivotal results. Field observations indicate short dispersal distances for the vast majority of fruits as well as a high level of directional asymmetry for both species of Carpinus. This asymmetry was intensified in the environment with an open vegetative structure, consistent with wind variability being the primary driver of dispersal distances. Migration simulations that incorporate local dispersal processes suggest low migration potential with a high level of directional asymmetry. Conclusions. Results stress the importance of rare long-distance-dispersal events in circumventing dispersal limitation in Carpinus and identify an important directional aspect to the process of wind dispersal. Because of the significant relationship found between dispersal patterns and wind directionality, the addition of a direction parameter to dispersal analyses and models could enhance the understanding of historic tree population dynamics, more accurately predict future movements, and inform conservation strategies of abiotically dispersed organisms. The enhanced asymmetry found in open forest structures makes it even more important to consider wind direction for predictive methods and conservation approaches as environments become more open due to forest clearing and other human disturbances. [ABSTRACT FROM AUTHOR]

Aim Dioscorea (Dioscoreaceae) is a predominantly pantropical genus (< 600 species) that includes the third most important tropical tuber crop and species of pharmacological value. Fossil records from both the Northern and Southern Hemispheres were used to test hypotheses about the origin of the genus Dioscorea, and to examine potential macroevolutionary processes that led to its current distribution. Location Pantropical distribution. Methods Divergence times were estimated using the most comprehensive phylogeny of the group published to date based on plastid sequences and fossil calibrations, applying a relaxed-clock model approach. Ancestral areas and range shifts were reconstructed using time-stratified likelihood-based models, reflecting past continental connectivity and biogeographical models incorporating the spatial range of fossils. Results Fossil-informed biogeographical analysis supported colonization of the Nearctic by ancient yam lineages from the western Palaearctic and subsequent migration to the South. Most of the pantropical South American, African and Southeast Asian lineages experienced a relatively recent diversification in the Oligocene-Miocene. Long-distance dispersals were inferred for the colonizations of the New World, Africa and Madagascar. Main conclusions Dioscorea likely originated between the Late Cretaceous and the Early Eocene in the Laurasian Palaearctic, followed by possible dispersal to South America via the Eocene North Atlantic Land Bridge. [ABSTRACT FROM AUTHOR]

Premise of research. Understanding how various organisms respond to previous changes in climate could provide insight into how they may respond or adapt to the current changes. Conopholis americana has a broad distribution across eastern North America, covering both previously glaciated and unglaciated regions. In this study, we investigated the postglacial history and phylogeographic structure of this parasitic plant species to characterize its genetic variation and structure and to identify the number and locations of refugia. Methodology. Molecular data from 10 microsatellite markers and DNA sequences from the plastid gene/introns (clpP) were obtained for 281 individuals sampled from 75 populations spanning the current range of the species in eastern North America and analyzed using a variety of phylogeographic methods. Distribution modeling was carried out to determine regions with relatively suitable climate niches for populations at the Last Glacial Maximum (LGM) and present. Pivotal results. We inferred the persistence of a minimum of two glacial refugia for C. americana at the LGM, one in north-central Florida and southern Alabama and another in the Appalachian Mountains near the southern tip of the Blue Ridge Mountains. High levels of genetic diversity were observed across the southern Appalachian Mountains, the region where populations from two refugia come together following recolonization northward. Conclusions. The genetic and geographic patterns revealed by our results provide further evidence of the dynamic nature and phylogeographical history of eastern North American taxa. The discovery of a distinct southern lineage is in agreement with the location of a previously proposed southern glacial refugium spanning across Florida, southern Georgia and Alabama, and the Lower Mississippi Valley. The second lineage is dominant across the present northern range of the species and is hypothesized to have been located in the southern extent of the Blue Ridge mountain range of the Appalachian Mountains at the LGM. [ABSTRACT FROM AUTHOR]

Premise of research. The genus Mucuna has a pantropical distribution and comprises approximately 105 species, many of which show great economic value for forage, ornament, and medicine. To date, phylogenetic relationships within Mucuna have not been investigated using molecular data. The aim of this study was to build a phylogenetic framework for Mucuna to address questions about its monophyly, infrageneric relationships, divergence times, and biogeography. Methodology. We sequenced plastid (trnL-F) and nuclear ribosomal (internal transcribed spacer) regions and applied Bayesian and maximum likelihood analyses. An ancestral area reconstruction coupled with a divergence time analysis was used to investigate the historical biogeography of the genus. Pivotal results. Our results show that Mucuna is a monophyletic genus and that subgenus Stizolobium is a monophyletic group within it. We present here the analyses and results that support the need to recircumscribe subgenus Mucuna and to segregate a small group of species with large fruits into a newly proposed subgenus (to be described formally elsewhere after additional investigations). Conclusions. On the basis of ancestral area reconstruction and divergence time analyses, we conclude that the genus Mucuna originated and first diversified in the Paleotropics around 29.2 Ma and achieved a pantropical distribution through multiple long-distance dispersal events, which were facilitated by the occurrence of seeds adapted to oceanic dispersal. [ABSTRACT FROM AUTHOR]

Summary: Regions harbouring high unique phylogenetic diversity (PD) are priority targets for conservation. Here, we analyse the global distribution of plant PD, which remains poorly understood despite plants being the foundation of most terrestrial habitats and key to human livelihoods.Capitalising on a recently completed, comprehensive global checklist of vascular plants, we identify hotspots of unique plant PD and test three hypotheses: (1) PD is more evenly distributed than species diversity; (2) areas of highest PD (often called 'hotspots') do not maximise cumulative PD; and (3) many biomes are needed to maximise cumulative PD.Our results support all three hypotheses: more than twice as many regions are required to cover 50% of global plant PD compared to 50% of species; regions that maximise cumulative PD substantially differ from the regions with outstanding individual PD; and while (sub‐)tropical moist forest regions dominate across PD hotspots, other forest types and open biomes are also essential.Safeguarding PD in the Anthropocene (including the protection of some comparatively species‐poor areas) is a global, increasingly recognised responsibility. Having highlighted countries with outstanding unique plant PD, further analyses are now required to fully understand the global distribution of plant PD and associated conservation imperatives across spatial scales. This article is part of the Special Collection 'Global plant diversity and distribution'. See https://www.newphytologist.org/global-plant-diversity for more details. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to further advance our understanding of the species‐rich, and ecologically important angiosperm family Combretaceae to provide new insights into their evolutionary history. We assessed phylogenetic relationships in the family using target capture data and produced a dated phylogenetic tree to assess fruit dispersal modes and patterns of distribution. Location: Tropical and subtropical regions. Time Period: Cretaceous to present. Major Taxa Studied: Family Combretaceae is a member of the rosid clade and comprises 10 genera and more than 500 species, predominantly assigned to genera Combretum and Terminalia, and occurring on all continents and in a wide range of ecosystems. Methods: We use a target capture approach and the Angiosperms353 universal probes to reconstruct a robust dated phylogenetic tree for the family. This phylogenetic framework, combined with seed dispersal traits, biome data and biogeographic ranges, allows the reconstruction of the biogeographical history of the group. Results: Ancestral range reconstructions suggest a Gondwanan origin (Africa/South America), with several intercontinental dispersals within the family and few transitions between biomes. Relative abundance of fruit dispersal types differed by both continent and biome. However, intercontinental colonizations were only significantly enhanced by water dispersal (drift fruit), and there was no evidence that seed dispersal modes influenced biome shifts. Main Conclusions: Our analysis reveals a paradox as drift fruit greatly enhanced dispersal distances at intercontinental scale but did not affect the strong biome conservatism observed. [ABSTRACT FROM AUTHOR]