Study On The Flora Of Vascular Plant In Ordos Plateau

Ordos Plateau is located in 106°42'-111°27'E,37°35'-40°51'N,enclosed by the Yellow River in the East,North and West,bounded by the ancient Great Wall in the South and Southeast.It's a quadrilateral plateau,and it has diversified landforms.In this paper,based on the collecting,classifying,identifying a host of specimens and extensive references,combined with the data of the vegetation survey in this region,on the basis of previous work,using the basic principles of plant geography and plant ecology,we compared and analyzed the floristic composition,life form,water ecotype,floristic geographic element,endemic species,and protected plants in Ordos plateau of the vascular plants,as well as the flora between the plant ecoregions in Ordos Plateau and its adjacent areas.Make to the following conclusion:1.There are 889 species(including subspecies,varieties,forms)of vascular plant in Ordos Plateau,belonging to 101 families and 382 genus,including 5 families 6 genus and 10 species of ferns,including 3 families 5 genus and 9 species of gymnosperms,76 families 288 genus and 662 species of dicotyledons and 17 families 83 genus and 208 species of monocotyledons.The research also discovered 3 new recorded species of Inner Mongolia,14 new recorded species of Shaanxi Province and 70 new species of Ordos Plateau.There are 9 local and semi-local endemics plants and 48 rare and endangered plants under protection in Ordos Plateau.2.The vascular plants in Ordos Plateau are mainly perennial herbs and mesophyte plant,the flora being predominated by the temperate distribution types(excluding world component),Temp.Asia element being predominated among temperate elements,in addition,E.Asia and Ancient Mediterranea also occupies a prominent position in the region.3.At the family level,the vascular flora of ordos plateau is dominated by Temperate element,followed by Tropical element,followed by Ancient Mediterranean element,and has no E.Asia element.At the level of genera,Temperate element dominate,followed by Ancient Mediterranean element,Tropical element rank the third,and E.Asia element occupy a small proportion.At the level of species,Temperate element is dominant,Ancient Mediterranean element is second,and E.Asia element is the third.The influence of Temp.Asia element,E.Asia element and C.Asia element was higher in each plant ecological zone.4.Eight plant ecoregions in Ordos Plateau in this paper,according to its geographic conditions and life form,similarity of coefficient,distance of flora relationship,characteristics of vegetation types,is divided into 5 districts: ordos high plain district,loess hill-gully region district,Hobq district,western Otog district and Mu Us sand land district.5.Compared with adjacent area in flora,Ordos Plateau,Helan Mountains,Xilingol Plateau and Yinshan Mountains are predominated by the temperate distribution types,reflects the distinctive characteristics of temperate zone and little tropical ones.By comparison flora relationship of Ordos Plateau with its adjacen area,Ordos Plateau has the highest similarity and closest relationship with Yinshan Mountains,followed by Helan Mountains,the lowest similarity and the farest relationship with Xilingol Plateau.