Study On Orchid Flora In Qinling Mountains

The Qinling Mountains area is one of the most abundant and highest flora differentiation rate of wild orchids in China.The distribution of wild orchids greatly reflected the characteristics of wild orchids' distribution from tropical to temperate regions in the world.It plays an important roles for understanding the changing distribution and species differentiation of wild orchids.Combined the related records of orchids in Qinling Mountains and the field investigation for some counties of Qinling Mountains,Taibai,Fuping and Yangxian with some herbarium collections in the Northwest Agriculture and Forestry University,the list of orchid plants in Qinling Mountains was sorted systematically.We statistically analyze of the orchid flora firstly,then account for the plant geographical distribution location of Orchidaceae basing on the data of vertical distribution,combining with the GIS system study the horizontal and vertical pattern of orchids in Qinling Mountains.Finally,the main results are as follows:(1)the unique geographic location and complex climate conditions of Qinling Mountains provides a variety of environment for orchids growth and reproduction.Orchid species are rich,a total of 52 genera and 149 species.There are 14 genera for monotypic genera and few species genera accounting for 26.9% of total genera of Orchidaceae in the region.70 endemic species belong to China accounting for 47% of the total number of orchids,and 9 endemic species belong to Qinling Mountains accounting for 6% of the total species of orchidaceae.Complex life types are terrestrial,epiphytic,semi epiphytic and saprophytic.The mainly terrestrial life types has 116 species accounting for 77.9% of the total species;the epiphytic type includes 19 species accounting for 12.8%;the hemiepiphytic type has 2 species,accounting for 1.3% and 12 species for saprophytic type accounting for 8%.(2)the complex geographical genera composition of orchid flora in Qinling Mountains can be divided into 10 distribution types and 4 subtypes including 29 temperate genera,accounting for 58% and 21 tropical genera about 42% of the total genera excluding cosmopolitan.It reflects the orchid flora in Qinling Mountains have relative relationship with the tropical flora.Through the analysis of geographical elements,it can be seen that the total of 6 distribution types and 2 subtypes of which 67 species distributed in the temperate zone,accounting for 45%.70 Chinese endemic species mainly is mainly distributed in southwestern-Qinling Mountains-central China-East China.It reflects the close ties among these areas.Therefore,the orchid flora in Qinling Mountains have rich species,complex composition,significant temperate characteristics,ancient origin,variety of endemic plants,rare and endangered plants gathered.(3)the uneven distribution of orchid in Qinling Mountains and hot distribution mainly is concentrated in Neixiang-Xixia-Luanchuan of the eastern part of Qinling Mountains,Fuping-Taibai Mountain of the middle Qinling Mountains and Wenxian-Zhouqu of the west Qinling Mountains.There are 124 orchid species in hotspots accounting for 83.2% of the total orchid in Qinling Mountains.76 species are distribute in Zhouqu Neixiang-Xixia-Luanchuan,72 species distributed in Foping Taibai and 48 species distributed in Neixiang-Xixia-Luanchuan.At county level orchid are widely distributed for example 64 kinds of species in Wenxian County,50 species in Foping County,49 species in Taibai County.As well as the distribution of Chinese endemic orchid species in Qinling Mountains which live in the area of Longnan and Foping is basically similar to the Orchidaceae distribution in Qinling Mountains.27 Chinese endemic orchid species are in Wenxian,20 species in Fuping,and 19 species in Zhouqu,17 species in Taibai.The widely vertical distribution of Orchidaceae plants in Qinling Mountains showed a single peak trend at an altitude 1400~1600m.65 species accounting for 43.6% of the total species are among the interval.While the vertical distribution of 23 Chinese endemic species are mainly in the elevation of 1200~1600m accounted for 32.8% of the total Chinese endemic species in Qinling Mountains.