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Disanthus cercidifolius subsp. longipes is an endangered species in China. Genetic diversity and structure analysis of this species was investigated using amplified fragments length polymorphism (AFLP) fingerprinting. Nei's gene diversity ranged from 0.1290 to 0.1394. The AMOVA indicated that 75.06% of variation was distributed within populations, while the between-group component 5.04% was smaller than the between populations-within-group component 19.90%. Significant genetic differentiation was detected between populations. Genetic and geographical distances were not correlated. PCA and genetic structure analysis showed that populations from East China were together with those of the Nanling Range. These patterns of genetic diversity and levels of genetic variation may be the result of D. c. subsp. longipes restricted to several isolated habitats and "excess flowers production, but little fruit set". It is necessary to protect all existing populations of D. c. subsp. longipes in order to preserve as much genetic variation as possible.

PREMISE OF THE STUDY: Phylogenetic analysis of DNA sequence data has changed our view on the evolution and systematics of plant taxa. Based on the phylogenetic analysis of several molecular markers, fruit anatomy, and pollen morphology, the genera Altingia and Semiliquidambar were formally transferred to the genus Liquidambar. The new species of Liquidambar from the Eocene of South China significantly extends our knowledge of the variability of the morphological characters of this genus in the geological past. Fossil leaves in conjunction with data on the associated reproductive structures allow us to make inferences about patterns in the evolutionary history of Liquidambar. METHODS: Fossil leaves and associated reproductive structures preserved as impressions were described and compared with the corresponding organs of extant and fossil relatives. The morphological variation of numerous leaves was examined by stereomicroscopy. KEY RESULTS: Liquidambar maomingensis sp. nov. is characterized by polymorphic leaves including both palmately lobed and unlobed leaves. This study presents the first observations of such dimorphism in the fossil record of Liquidambar leaves. Two distinct leaf groups are interpreted as sun and shade leaves. CONCLUSIONS: The fossil leaves and associated infructescences from Maoming probably belong to the same plant. The occurrence of fossil leaves similar to those of extant species previously considered with in Semiliquidambar and Liquidambar with the associated infructescences close to those of Altingia provide paleobotanical evidence that justifies combining the genera Liquidambar, Altingia, and Semiliquidambar into the single genus Liquidambar as recently proposed based on molecular markers. [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]

The study of fossil plant–biotic (mainly arthropod) interactions offers an opportunity to understand the evolutionary process in palaeoecosystems and their response to climate fluctuation. Despite the importance of such investigations, not much is known about plant–arthropod associations from the Cenozoic floras of Asia. Exceptionally diverse Eocene floras from adjacent Maoming and Changchang sedimentary basins of southern China provide valuable insights into low-latitude palaeoecosystems. These floras indicate different intensities of plant–arthropod interactions and probably viral, bacterial or fungal infection. Two upper Eocene floras from the Maoming Basin are markedly distinct from two approximately contemporaneous middle Eocene floras of the Changchang and Maoming basins in exhibiting much more abundant and diverse plant damage types (DTs). For equivalent comparisons we focus on well-sampled fossil leaves of Liquidambar L. (Altingiaceae) present and relatively abundant in both basins. L. maomingensis and Liquidambar sp. 1 from both upper Eocene Maoming floras exhibit mainly external foliage feeding. In contrast, almost only galling occurs on Liquidambar sp. 2 leaves from the middle Eocene Changchang flora. The differences in the diversity and frequency of DTs in the studied palaeofloras could have been affected by a progressive warming and increase in climate seasonality over the middle–late Eocene interval as well as by habitat conditions and plant successional status. We hypothesize that L. maomingensis and Liquidambar sp. 1 from the Maoming Basin inhabited the early successional riparian forests on an alluvial plain, whereas Liquidambar sp. 2 from the Changchang Basin was a component of more mature plant communities. [ABSTRACT FROM AUTHOR]