Studies on Geographical Distribution Pattern of the Subgenus Pogonophace (Fabaceae: Astragalus) in China Using GIS Technique

The geographical distribution maps of the subgenus Pogonophace (Fabaceae: Astragalus) in China were designed and drawn using GIS cartographic technique. The species of the subgenus and county of China were treated as the basic composition units in the GIS cartographic technique. Most of the distribution maps were shown in spots. The distribution pattern of the subgenus illustrates that it is a peculiar group to adapt the cold alpine environment and distribute mainly in Hengduan Mountains and Himalayas. According to the geographical distribution maps and some statistic analyses, Hengduan Mountains region is suggested to be the distribution center, differentiation center and endemic center of the subgenus. Some vicariance traces at levels of the species or sections are very interesting among the distribution patterns of the subgenus and shown clearly in the maps.