Tethys retreat and Himalayas-Hengduanshan Mountains uplift and their significance on the origin and development of the sino-himalayan elements and alpine flora

The Tethyan Tertiary Flora was only conserved and developed in E Asian for monsoon climate bringing ample summer rain up to today. Therefore, most of subtropical evergreen broad-leaved forest occurring in Himalayas-Hengduanshan Mountains are the descendant of the Tethyan Tertiary Flora. After Neogene, the Himalayas-Hengduanshan Mountains uplifited caused the semiarid or arid flora of Mediternanean turning to adapt to alpien environment and gradually differentiated and developed in these regions. Through analysis of the origin of sclerophyllus oaks forest in Himalayas-Hengduanshan Mountain and the Euroasian disjunction in some examples: Helleborus, Meconopsis, Acanthochlamys, Notholirion and Coriaria, as well as the descendants of Tethyan flora, such as Piptanthus, Lamiophlomis, Notochaete, Phyllopnyton, exsiting in the regions, showed that quite a part of Sino-himalayan elements and modern alpine plants of Himalayas-Hengduanshan Mountains originated from the semiarid or arid flora of Mediterranean.