Paliurus Fruits from the Oligocene of South China and Their Phytogeographic Implications.

Paliurus favonii Unger is recognized and described based on fruits from the Oligocene Ningming flora of Guangxi, South China. Characteristics of the present specimens include circular winged fruits that are 10.0-11.5 mm in diameter with a central endocarp at 3.0 to 4.0 mm in diameter. The specimens fall into the morphological range of the fossil species P. favonii, which has been observed in other Cenozoic sites in the Northern Hemisphere. The present discovery represents the lowest latitude distribution of P. favonii in the world, and we are presenting the first P. favonii fossil described with detailed cuticular characteristics from China. Further, this finding demonstrates that the genus existed in the Oligocene Ningming region, South China, and provides new information for understanding the fossil history. The dispersal mode for winged fossils demonstrates that wind dispersal is well-represented in the Oligocene Ningming flora.

A new species of Meliolinites associated with Buxus leaves from the Oligocene of Guangxi, southern China.

A new species of Meliolinites (fossil Meliolaceae), M. buxi sp. nov., is reported from the Oligocene Ningming Formation of Guangxi, South China. The fungus has hyphopodia characteristics of extant Meliolaceae, such as thick-walled, branching hyphae with appressoria and phialides. However, these fossils entirely lack mycelial or perithecial setae and have only a few phialides, thereby distinguishing the new species from most known species. The fungus was discovered on the adaxial and abaxial cuticles of several fossilized Buxus leaves. Thickening and twisting of cell walls in the Buxus leaf cuticle, along with the parasitic feeding strategy of the extant Meliolaceae, suggest that a parasitic interaction between Buxus and M. buxi seems feasible. The distribution of modern Meliolaceae suggests that they live in warm, humid subtropical-tropical climates. It is possible that the presence of M. buxi indicates a similar climatic condition. The co-occurrence of large-leaf Buxus and floristic comparisons of the Ningming assemblage also corroborate this conclusion.