Relationship between Morphological Differentiation and Elevation of Wild Cymbidium tortisepalum in Diqing of Yunnan Province

Diqing, a region rich in geological landforms, biological and landscape diversity located in the junction of three province namely Yunnan province, Tibet and Sichuan province, is one of the most important distribution areas of wild Cymbidium tortisepalum. In this study, 14 wild C. tortisepalum populations were collected in the area including Weiden Township of Weixi County and Yanmen Township of Diqing during the field investigation, and the morphological characteristics of plant height, length and width of leaf, etc. were measured from August 1st to 25th in 2013. The results showed that there was a significant negative correlation relationship between the morphological characteristics of plant height, leaf length and leaf width and altitude of distribution of C. tortisepalum (PR2=0.724 8), the shorter the plants(R2=0.581 2)and leaves become (R2=0.463 4), however, leaf number of C. tortisepalum was affected less by altitude. The study presented explicitly that northwestern, western and northern slope are the main distribution area of C. tortisepalum. These results illustrated that the morphological characteristics of C. tortisepalum were affected by the habitat factors such as elevation, gradient and slope direction of population distribution site. The results can provide a foundation for further study and protect the rare orchid.