Discuss on the Rhododendron geographical distribution types and their cause of formation in China
A distribution type system which involves the 7 sects and 49 subsects was established,according to the pro duction of the botanical taxology and geography,especially the Rhododendron distribution and their change and rule of the modern and historical environment from the east of China to Himalayas, based on the distribution type of the 3 subgenus class . The results showed that the system brought forth the Rhododendron distribution status about the 4 basic units of geography from the east to the west of China, especially the position and number distribution of these sects and subsects of different size, character and evolution degree which belong to subgen. Rhododendron and sub gen. Hymenanthes and showed the profound effect to the Rhododendron distribution pattern from the east to the west where the topography was from lower to higher and the change of the biologic geology history was from the steadier state to the un-steadiest state. It was seen that the distribution area or the mass distribution area, the sects and subsects were the larger, wider,more original and to belong to subgen. Hymenanthes,leaning to the Mt. Narrow Hengdu-ans or their east area, which were the smaller, narrower and endemic, younger and to belong to subgen. Rhododen dron, lean to the Mt. (Narrow) Hengduans and their west. At the same time, the mass distribution area of Rhododen dron was the barrier to disturb the pervasion and transfer for some taxa in the west-Sichuan Mountains, Mt. Narrow Hengduans and Mt. Himalayas where are important in the modern Rhododendron distribution area and pattern of for mation in China. It would be a principal axis for the change of the groups and its distribution types under Rhododen dron in China that the geographic environment changes from the east to the west.
Rhododendrongeographical distribution typesect and subsectChina