The Areal-types of the World Families of Seed Plants

The areal-type means distribution map of certain plants always same or nearly same. This is an important method in floristic research to divide distribution into different areal-types.More than 3116 genera of seed plants have been recorded in China.They have been classified into 15 areal-types and 37 subtypes.The certain number represent certain areal type such as number 2 always means pantropic distribution pattern.After repeated to tests and uses,it has been proved that characteristics and relationships of each areal type can be showen by such classification.A classification precept of families of seed plants of the world has been proposed at present paper.The families of seed plants of the world can classified into 18 areal types and 74 subtypes.Among these areal-types,areal-types 1 to 15 are coincidence with those of Chinese seed plants.Areal-type 16-18 are the kinds of distribution pattern which can not be found in China.A distribution patterns of world families of seed plants is listed at present paper as well.This classification is a key to help us to understand development of flora of seed plants of the world and become a base of regionalization of world flora.