关键词: 牻牛儿苗科, 地理分布, 四川

Abstract: There are 53 species and 2 varieties of Geraniaceae plants in Sichuan. They belong to 3 genera, which are Geranium (49 species and 2 varieties), Erodium (2species)and Biebersteinia (2 species). The genus areal-types of these genera areCosmopolitan (Geranium), Mediterranea to Temp. and Trop. Asia, Austriiasia & S.Amer. disjuncted (Erodium) and Mediterranea, West Asia to Central Asia(Biebersteinia). The horizontal and vertical distributions of these species in Sichuanhave been studied. Only 23 species of one genus (Geranium) distribute in the eastof and around Sichuan Basin. They account for 43% of the total species of Geraniaceae in Sichuan. 32 species of Geranium, which account for 60% of the total numberof Geraniaceae species, distribute in the southwest mountainous area where the Geraniaceae species are concentrated. In the northwest of Sichuan, the generanumber increases along with the increase of latitude. All three genera are distributedhere. But the number of species of Geranium decreases. In the view of verticaldistribution, the following results have been revealed: (1) 44 species and 2 varietiesof Geranium distribute in the evergreen broadleaf forest zone in the east of SichuanBasin and southwest mountainous area. They account for 83% of the total speciesof Geraniaceae in Sichuan and most of them distribute in the southwest mountainous valley vegetation area. (2)There are 25 species of Geranium and Erodiumdistributed in the mountainous and valley conifer zone in the west of Sichuan.They account for 47% of the total family in Sichuan. (3) 12 species of Geranium.Erodium and Biebersteinia are distributed in the mountainous shrubs and meadowsin the northtvest of Sichuan, which is the only area in Sichuan where Biebersteinia plants grow.

Key words: Geraniaceae, Geographic distribution, Sichuan