Abstract: From the following facts it follow that the Qing-Zang plateau Began ro elevate since the Tertiary.From the viewpoint of the area where we discovered the plants. We have a survey of the Polytrichaceae in Tibet mainly distributed in SE.Tibet and S>Tibet.This area is just along the valley of the Yalu Tsangpo(Yalu Tsangpo River).According to the theory of the continental drift,this area may well be the seam where the northern edge of the India Plate and the southern edge of the elements of Asia meet.Thus the plants of this area include not only the elements of Laurasia,but also those of Gondwanaland.As a result of this,this plants os this area characteristic if complexity of elements and greatness of species.It is because of the creash of the India plate and the continent of Asia that the Qinghai-Xiang(Chinghai-Tibet) area is uplifed by the impact of the crash.

Key words: Tibet