Abstract: The northern Gaoligong Mountains is rich in species and it is one of the richest areas of plant diversity in the world. So far, 2 514 native species and 302 varieties (or subspecies ) belonging to 778 genera in 172 families were recorded. Based on the statistics and analysis of families, genera, and species, a floristic study on the seed plants of the northern Gaoligong Mountains was carried out. The results are as follows: 1) The main floristic feature is temperate, but it is greatly influenced by tropical elements. The floristic relationships are complex, and many kinds of distribution types are represented here; 2 ) During the long geological history, the process of fusion and development among Gondwanaland and Laurasia floras is a key to the origin of modern flora of the northern GaoligongMountains. In addition, some elements that came from Indo-Malaysia and North Temperate ( especial Eastern Asia ) differentiated into variously rich endemic taxa in the region.
Based on the tropical Asian flora , all of the endemic taxa and the two elements mentioned above together changed into the framework of the present flora during geological time; 3) The horizontal and vertical vicariance of the flora is evident in the northern Gaoligong Mountains. The disjunct distribution is also evident, the main disjunct type is a distribution pattern
from northwest to southeast Yunnan or only distribution in the southwest of the line that along from northwest to southeast Yunnan; 4) The endemism within the flora is rich and the endemic elements differentiated strongly in the region. The palaeoendemic and neoendemic elements can co-exist in the region, but the neoendemic elements are dominant. These data show that northern GaoligongMountains not only is a refuge for some ancient floristic elements but also is a differentiation center for some new floristic elements.

Key words: The northern GaoligongMountains