The Floristic Characteristics in the Region of Bayan Har Mountains

Bayan Har Mountain which owns a land area about 84 000?km~2 and a height range above sea level from 3 600-5 369?m,is located at S.Qinghai between 32°20′-35°15′ N and 94°50′-101°45′ E.There are 1 116 species of seed plants belonging to 46 families and 295 genera in this area.The floristic characteristics are summarized as follows: 1)Analysis of the generic distribution pattern demonstrated that they mainly consist of north temperate elements,except 9 genera which have a distribution from tropical to temperate zone and only a few or one species of them were found in this area. 2)Analysis of the specific distribution pattern demonstrated that most of the species (excluded those endemic to China) belong to C.Asia and E.Asia elements especially to those with distribution from C.Asia to both Himalaya and S.W.China or Sino-Himalaya.By the evidence mentioned above,it easily comes to a conclusion that the species belonging to temperate elements had achieved complete dominance in this area and always distributed in plateau and alpine mountains. 3)In the southeast of this area,the ecological environment and the source of floristic elements differ from the others.The species from E.Asia and its subtype Sino-Himalaya concentratively collected at this place.It should be regarded as a corridor of the floristic elements from Hengduan Moutains and W.Qinling Mountains. 4)Analysis of the endemic species from China demonstrated that the flora is most closely related to those of Hengduan Mountains and S.Kansu. 5)The species under alpine specialization and selection of the alpine ecological factors obtained the adaptive characters to resist the frigidity and the aridity. 6)The plants with cold-resistance are always accompanied with dual species abilities of drought-tolerance and wet-tolerance.These characters of the plants are also reflected in their distribution. 7)The floristic nature and characteristics basically are in accord with those of Tangut area,in other words,it is only a part of Tangut flora.