Fossil wood of Chinese white pine (Pinus armandii Franch.) from the Late Pleistocene deposits of Maoming Basin of South China provides the first megafossil evidence for glacial expansion of the range of a cold-tolerant species in low latitudes.

The bark fulfils several essential functions in vascular plants and yields a wealth of raw materials, but the understanding of bark structure and function strongly lags behind our knowledge with respect to other plant tissues. The recent technological advances in sampling and preparation of barks for anatomical studies, along with the establishment of an agreed bark terminology, paved the way for more bark anatomical research. Whilst datasets reveal bark’s taxonomic and functional diversity in various ecosystems, a better understanding of the bark can advance the understanding of plants’ physiological and environmental challenges and solutions. We propose a set of priorities for understanding and further developing bark anatomical studies, including periderm structure in woody plants, phloem phenology, methods in bark anatomy research, bark functional ecology, relationships between bark macroscopic appearance, and its microscopic structure and discuss how to achieve these ambitious goals.

The bark structure of Adansonia digitata L. is described in detail. Characters of the bark that are shared with other Malvaceae include the presence of strongly dilating rays, mucilage cells and cavities, druses of calcium oxalate in the cells of cortical parenchyma and phloem rays, a storied arrangement of sieve tube members and axial parenchyma strands, the presence of secondary phloem fibers and their arrangement into tangential bands. The secondary phloem fibers are longer (2.8–8.6 mm) and more abundant than the libriform fibers (1.7–2.2 mm) in the wood of this species. The abundance of parenchyma in both axial and radial parts of the secondary phloem and in the pseudocortex is a noteworthy feature. Due to the complementarity of fibrous and parenchymatous tissues, the secondary phloem can provide substantial mechanical benefits and apparently play an important role in the biomechanical stability of the trunk. The meristematic capacity of dilated phloem rays and the pseudocortex allow for subs... RÉSUMÉ Anatomie de l'écorce d'Adansonia digitata (Malvaceae). La structure de l'écorce d'Adansonia digitata L. est décrite en détail. Les caractères communs avec les autres Malvaceae comprennent la présence de rayons fortement dilatés, ainsi que de cellules et de poches à mucilage, des cristaux d'oxalate de calcium en oursins contenus dans les cellules du parenchyma cortical et des rayons phloémiens, une disposition stratifiée des éléments conducteurs du phloème et des massifs de parenchyme axial, la présence de fibres associées au phloème secondaire et disposées en bandes tangentielles. Ces fibres sont plus longues (2,8–8,6 mm) et plus abondantes que les fibres libriformes (1,7–2,2 mm) reconnues dans le bois de cette espèce. L'importance du parenchyme, tant dans les sections axiales et radiales du phloème secondaire, que dans le pseudocortex, est un fait remarquable. En raison de la complémentarité des tissus fibreux et parenchymateux, le phloème secondaire peut participer efficacement au soutien et semb...

Factors influencing diversification rates may be of intrinsic (e.g. morphological novelties) or extrinsic (e.g. long-distance dispersal, availability of ecological niches) nature. Growth habit may influence diversification rates because herbaceous plants often have shorter generation times and a more pronounced r reproductive strategy than their woody relatives. We examined life history and habit evolution, wood anatomy and biogeographical history of Apiaceae tribe Apieae in conjunction with diversification rate analysis to explore which factors may have affected clade species richness and to elucidate the constraints on the evolution of secondary woodiness in this group. We demonstrate that diversification rates are similar in morphologically homogeneous and diverse clades and in herbaceous and woody lineages. The only clade with a significantly elevated diversification rate is Southern Hemisphere Apium, in which diversity probably resulted from several long-distance dispersal events. We also show that wood anatomy in herbaceous and woody species does not differ considerably regardless of their continental or insular origin, but it is affected by stem architecture and plant reproductive strategy. As the taxonomy of Apieae suffers from inflation with numerous monotypic genera, we propose to include Canaria in Rutheopsis, and Foeniculum, Schoenoselinum, Ridolfia and Pseudoridolfia in Anethum.

Erica comprises ~860 species of evergreen shrubs and trees ranged from Europe to southern Africa and Madagascar. Wood structure of the around 20 European species is well studied, but despite its relevance to adaptation across the wider geographic range, it has not yet been explored across the much greater diversity, particularly of southern African lineages. In this study, we examine wood structure of 28 Erica species from southern Africa. In the African Erica clade, loss of scalariform perforation plates could be driven by increased aridity and seasonality in the mid-Miocene, and its re-gain can represent an adaptation to freezing in the high elevation species E. nubigena. As vessels in Erica are mostly solitary, imperforate tracheary elements probably form a subsidiary conduit network instead of vessel groups. Increase of ray frequency in habitats with a prominent dry and hot season probably facilitates refilling of vessels after embolism caused by water stress. Wider rays are ancestral for the lineage comprising African Erica and the Mediterranean E. australis. The negative correlation between ray width and expression of summer drought is consistent with Ojeda’s model explaining the diversification of seeders and resprouters among southern African Erica.