A Study On Floristc Phytogeography Of Seed Plants In Lancangjiang Nature Reserve, Yunnan Province

Lancangjiang Nature Reserve(LNR) is located in Lincang,Yunnan Province,China.The coverage of LNR is N23°07′～25°02′and E 99°07′～100°25′.The elevation rising from 1,850m to 3,429.6m.The main types of forest in LNR are Semi-humid evergreen broad-leaved forest,Mid-mountain moist evergreen broad-leaved forest,Summit mossy dwarf forest,Alpine meadow etc..The dominate families of the forest includes Fagaceae,Lauraceae,Theaceae,Magnoliaceae and Aquifoliaceae.On the basis of studies of traditional floristic phytogeography,this paper analyzed the flora of family,genus,species,add analysis of species richness along an altitudinal gradient,vertical distribution of the geographical elements and floristic equilibrium point. LNR includes:136 families,425 genera and 1,051 species(include subspecies)above 3000 collected specimens.These investigations of floristic elements show:this reserve has sound complex floristic and geographic elements,and almost all kinds of distribution types are more or less represented here.In this region,the total of 136 families can be divided into 11 types,the total 428 genera can be divided into 14 types and 15 subtypes,the total 1,051 species can be divided into 15 types,3 subtypes and 8 forms,the total 501 endemic to China species can be divided into 3 subtypes and 8 forms.Among the tropical distribution patterns,tropical Asia and Pan-tropic distribution are the richest.The East Asia distribution are the richest among the temperate distribution patterns.The flora of the region is closely linked with the flora of the South and South-west Yunnan.From the standpoint of all of China,the flora of the region is closely linked with the flora of the South-west China.From the standpoint of the East Asia,the flora of region is closely linked with the flora of the Eastern Himalayas.The floristic characteristic of seed plants of LNR is subtropic to temperate.In flora composition,there are 66 tropical families,occupy 67.35% to total families and 32 temperate families that occupy 32.65% to total families,but without typical tropic families.And there are 208 genera that occupy 52.93% to total genera and 185 temperate genera that occupy 47.07% to total genera.The floristic elements of 52.93% tropical genera(208 genera)and 47.07% temperate ones(185 genera).Tropic characteristic of genera much lower than tropic characteristic of family.The floristic elements of 30.40% tropical species(318 species)and 69.60% temperate...