Format: ORAL

Hong-Hu Meng

1 Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China 2 Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Nay Pyi Taw 05282, Myanmar

Southeast Asia is recognized as global biodiversity hotspots with conservation priority. Since the mid-19th Century, Southeast Asia has been widely considered as one of the most important cradle and frontiers of biogeography. This connection stems from the groundbreaking field works of Alfred Russel Wallace, who spent 8 years to extensively explore the regions and proposed the geographic distribution patterns of fauna in Malesia. However, many distribution patterns were from fauna or animal diversity. Thus, more plant taxa are necessary to explore the biogeographic patterns in Southeast Asia. Here, some superficial ideas and recommendations are presentaed to adress the unresolved challenges of the field of biogeography in Southeast Asia from Engelhardia. The related information includes species delimitation, taxonomic revision, biogeographic patterns in the regions. The comprehensive taxonomic revision of Engelhardia will provide insights into Southeast Asia. As well, the results urge caution when using the concepts of subspecies and varieties in ordes to prevent confusion, particularly with respect to species delimitation for tropical and subtropical species. Also, biogeographic patterns of Engelhardia have told that the tropical elements were transformed from the tropical elements; Miocene cooling and the onset of the EASM facilitated the transformation of Engelhardia from the tropical Indochina Peninsula to subtropical China. The lineages anound Hainan Island, China mainland and Indochina Peninsula showed that Engelhardia dispersed from Chiang-nan to Hainan Island via land bridge, so thta drift of Hainan Island did not occurr, wchich was impossible to affect the evolutionary trajectory of plants. In all, I hope the works from Engelhardia will serve as a link between past and future, intends to be the gegainning of propaganda, and facilitates the flourishing development of biogeography in Southeast Asia.