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Many factors influence leaf anatomy and morphology in the crown of a tree, particularly those resulting from microclimatic differences between the periphery and the interior of the crown. These influences can be so strong that single species can produce different leaf forms in which shade and sun leaves exhibit consistently distinctive morphological and epidermal character sets. Here we show, using Liquidambar as a model system, that the principal morphological characters for distinguishing shade and sun leaves in two modern Liquidambar spp. with different lamina types (entire in L. chinensis and lobate in L. formosana) are the leaf lamina length to width ratio, the degree of development of venation networks, tooth size and tooth shape. The main epidermal characters are ordinary cell size and anticlinal wall outlines. Many fossils, however, are only preserved as impressions and morphological characters alone have been used to distinguish shade and sun leaf morphotypes. To evaluate the utility of our approach, populations of fossil Liquidambar leaves from the Eocene of southern China, preserved only as impressions, were categorized into sun and shade morphotypes. Recognition that sun and shade leaf morphological diversity exists in fossil populations will enable palaeobotanists to identify more reliably foliar polymorphisms that would otherwise be used to describe, incorrectly, different species. [ABSTRACT FROM AUTHOR]

Three new fossil species, two attributed to the genus Castanopsis ( C. nanningensis and C. guangxiensis ) and one to the organ genus Lithocarpoxylon ( L. nanningensis ) are described on the basis of well-preserved mummified wood from the upper Oligocene of Yongning Formation in the Nanning Basin, Guangxi Province, South China. The two species of Castanopsis represent the most ancient reliable wood record of this genus in China and also southeastern Asia, which is the center of diversity of extant species. The fossil leaf records of Castanopsis indicated this genus has migrated to South China in the late Eocene. This fossil wood evidence confirms the presence and persistence of Castanopsis in this region in the late Oligocene. In the Yongning Formation, the presence of numerous Fagaceae woods with faint or absent growth ring boundaries (in C. nanningensis ) occasionally associated with prominent ring-porous patterns, suggests that Guangxi (South China) had a seasonal (probably monsoonal) tropical climate during the late Oligocene. [ABSTRACT FROM AUTHOR]

The genus Paliurus is characterized by its distinctive orbicular-winged fruits and a trilocular (or bilocular) ovary. Macrofossil records suggested this genus was distributed widely in North America, Europe, and Asia during the Paleogene and Neogene, before its present limitation to Eurasia. In this study, we describe some Paliurus fossil winged fruits from the lower part of Youganwo Formation (middle Eocene) and Huangniuling Formation (late Eocene) of the Maoming Basin, South China. These fruits are recognized as Paliurus favonii Unger based on a detailed study on the fossil morphology and cuticle characteristics. This represents the earliest occurrence of Paliurus fossil fruits in eastern Asia, and to date is the world's lowest latitude appearance for this genus. The most ancient records of Paliurus throughout the world are from the middle Eocene of North America and the late Eocene of Japan, leading some researchers to conclude the Paliurus may have originated in North America. Molecular data, however, do not support this hypothesis. The present Paliurus fossil fruits provide new evidence for the origin and phytogeographic history of this genus. [ABSTRACT FROM AUTHOR]

* Premise o f the study: The fossil record of alder (Alnus) is well known in the Cenozoic deposits throughout the northern hemisphere, based on numerous reports of the distinctive pollen, cone-like infructescences, staminate inflorescences, and leaves. However, our understanding of the systematic position of these fossils relative to the modern phytogeny of the genus has been limited because most fossils were described from only one organ. * Methods: We examined well-preserved leaves and associated fruiting and staminate catkins from the middle Eocene, Clarno Formation, Oregon, USA by stereomicroscopy. In situ and dispersed pollen were cleaned with HF and acetolized for light and scanning electron microscopy. * Key results: We reconstructed a new extinct species based on multiple organs and discuss significant phytogeographic and phylogenetic implications for Alnus. Alnus clamoensis sp. nov. is described based on serrate leaves with 1-4 small teeth between each primary tooth, associated cone-like fruiting catkins with fruits in situ, and associated slender pollen catkins beating in situ 3- to 6-pored pollen with arci between the pores. Combined investigations of each organ indicate that they probably derive from the same species and can be confidently attributed to subgenus Alnus Furlow based on leaf architecture and pollen pore number frequency. * Conclusions: The Clarno fossils are most similar to the extant North American species of subgenus Alnus rather than to those from Asia and Europe, indicating that this modern subgenus was already distinct by the middle Eocene and that the intercontinental migration likely occurred earlier. [ABSTRACT FROM AUTHOR]

A new species, Altingioxylon hainanensis, is described from the Eocene Changchang Formation of the Changchang Basin on Hainan Island, South China. It is the first record of a fossil wood assigned to Altingiaceae found in China, and the most ancient evidence of wood for this family in eastern Asia. The new species is similar to A. rhodoleioides, known since the Miocene in India and Java Island, and to Altingia hisauchii from the Miocene to Pliocene of Japan. The close resemblance between these species and Liquidambar sp., known from the Middle Miocene of western North America, provides additional evidence for the migration of their ancestors from Asia to North America across the Bering land bridge during the Miocene. Distinctions in ray sizes between the eastern Asian specimens and their contemporaries from Europe to Kazakhstan is suggested as a result of the divergence between the large eastern Asian clade and the North American-west Asian clade within Altingiaceae during the Eocene-Oligocene. The presence of crystals in ray cells may be considered an ancestral condition that persists in the eastern Asian lineages up to the extant Altingia and Semiliquidambar, but which was lost in other Altingiaceae in the course of evolution. [ABSTRACT FROM AUTHOR]

Abstract: The modern distribution centre of the genus Craigia is situated in South China and adjacent northernmost Vietnam, but it was widely distributed in Europe, North America and East Asia during the Tertiary. Up to now, the genus Craigia includes only two extant and two fossil species. Based on a detailed study of the fossil material from the coal-bearing deposits of the Changchang Formation (Eocene) from the Changchang Basin of Hainan Island, China, Craigia hainanensis sp. nov. is established. This is the first fossil record of Craigia in its modern distribution centre which provides a new data on the origin and phytogeographic history of this genus. The distribution of extant and fossil Craigia in North America, Europe, Central and East Asia suggests that the Far East of Russia is a possible centre of origin of Craigia where the fossil record of this genus goes back to the Paleocene. During the Eocence global warming event, Craigia had dispersed rapidly to North America, Spitzbergen, East and Central Asia, and reached its modern distribution centre in South China no later than in the early Late Eocene. During the Oligocene and Neogene this genus continued to spread over Asia and further dispersed to Europe. [Copyright &y& Elsevier]

Abstract: A new species of Nelumbo Adanson is described from the Eocene of the Changchang Basin, Hainan Island, South China. This is the first comprehensive report on a fossil Nelumbo species from the Eocene of the Changchang Basin, Hainan Island. The co-occurrence of fruits, tubers, rhizomes with numerous adventitious roots, leaves, and receptacles indicates that the plants grew where they are preserved. These specimens, combined with palynological assemblage and other macrofossils, indicate a tropical or subtropical humid climate in the Changchang Basin from the late early Eocene to early late Eocene. [Copyright &y& Elsevier]

[Display omitted] • Valuable insight into impact of past climate changes on range dynamics of M. insignis. • Additional evidence of glacial expansion for montane species at low latitudes. • Offer protection strategy for low latitudes montane species respond to climate change. The Pleistocene Epoch, marked by significant climatic fluctuations and glaciations, profoundly impacted plant populations. However, our understanding of the influences of last glaciations on tropical-subtropical flora and vegetation remains limited due to insufficient data. Here, we present mummified wood of Magnolia insignis (Wall.) Bl. from the Upper Pleistocene (33–30 ka cal. BP) of Maoming, South China, providing direct evidence of a broader historical range for this species during the period prior to the LGM in the last glaciation. Combining these findings with results from MaxEnt modeling, we demonstrate an expanded range of M. insignis into lower latitudes during last glaciation with subsequent interglacial contraction. This represents the second documented case of such a scenario for a cold-tolerant high-elevation plant species at low latitudes. The results of MaxEnt modeling and a comparison of climatic data across different time periods indicate that the contraction of M. insignis from the Maoming and other low latitude regions of East Asia was driven by the increase in summer temperatures during Holocene. This study not only sheds light on the responses of cold-adapted mountainous species at low latitudes of East Asia to last glaciation, but also justifies the importance of their protection in the view of nowadays and future climate changes. [ABSTRACT FROM AUTHOR]