The fossils reveal the long history of evergreen broad-leaved forests in East Asia

subtropical evergreen broad-leaved forests in East Asia are a relatively unique type of plant in today's world, but extensive fossil records show that the entire northern hemisphere was covered by this vegetation in the early New Generation. Therefore, the study of its origin and evolution is of great significance to the exploration of the formation of vegetation and biodiversity patterns in the northern hemisphere. In the past, due to the lack of fossil evidence in East Asia, it is generally believed that The evergreen broad-leaved forests of North America and Europe are older, and that the existing areas in East Asia are only its "relics" or "museums". However, the discovery of paleo-era fossils in East Asia in recent years is gradually challenging this view.
new-generation Wenshan flora found in the Wenshan Basin in southeastern Fujian Province is by far the most abundant and diverse new generation of plant groups in China. It has an earlier geological age and plays an important role in solving the problem of the origin of evergreen broad-leaved forests in East Asia. The Paleoanth ecological research group of Xishuangpana Tropical Botanical Garden of the Chinese Academy of Sciences has carried out long-term paleo botanical research here and has carried out extensive cooperation with Kunming University of Technology in geology and physiology.
recently, researchers at the Xishuangdana Tropical Botanical Garden of the Chinese Academy of Sciences made new progress, and the results of the study were published in Plant Diversity.(
) is a small trees or shrubs of the tiger-eared
(
). This genus evergreen species is a common shrub plant in East Asian evergreen broad-leaved forests, and deciduous species is associated with warm temperate deciduous broad-leaved forests in East Asia-North America, so it is also a good material for studying the relationship between deciduous broad-leaved forests and evergreen broad-leaved forests. Recently, a leaf of the genus rat hedgehog was identified in the fossil collection of Wenshan flora. Under the guidance of Huang Jian, assistant researcher of the Paleo-Ecology Research Group of Xishuangpana Tropical Botanical Garden of the Chinese Academy of Sciences, Tian Yimin, a doctoral student at Kunming University of Technology, conducted a study of paleo botany. These leaf fossils have typical leaf vein characteristics: secondary veins, three-stage pulse ladder, with shedding tea teeth. By comparing with the study of leaf vein structure of the living species, it was determined that it belonged to the evergreen rat hedgehog group (
), and the most recent kinship species was
). Rat stings may originate in tropical Asia, but their diversity center is a subtropical region in southern China and an indicative species of evergreen broadleual forests. Combined with other groups found in flora, this type of vegetation existed as early as the Neolithy (about 30 million years ago).Based on both fossil records and biogeogeological analysis,
paper discusses the differentiation process between the evergreen and deciduous species of rat hedgehogs on all continents, and suggests that the production and expansion of deciduous are closely related to the cooling of the northern hemisphere after the ococene. (Source: Zhang Qingdan, China Science Daily)
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