关键词: 山茶属, 倍性, 核型, 细胞地理学

Abstract: In this paper, the origin and evolution of genus Camellia was discussed by cytogeographical method. The results were based on the information on chromosome numbers of 62 species and on karyotypes of 54 species in 10 sections, 52 and 45 of total species respectively. There was stable basis number (x = 15) and various ploidy (from 2x to 8x) in Camellia. Every section contained diploid and some of them were all diploid. Poly-ploid species were mainly in Sect. Camellia, Seci.Paraccimellia and Sect. Theopssis, and distributed in the north-east, west and north of distribution of Camellia, presenting the tendency that polyploid was more in the north and west than in the south. Karyotypical evolution in Camellia agreed with Stebbins theory, from symmetry to asymmetry. Sect.Archecamellia contained the most symmetrical karyotype and was the most primitive group in 10 sections; Sect. Camellia was the most advanced groups. Sect. Heterogenea, including C. yiavumensis, was not the most origninal group in Camellia, because of its high asymmetrical karyotype. Camellia might be origi-nated in Indochina Peninsula, then dispersed mainly to northern area and differentiated rapidly in the present distributio center ,Yunnan ,Guangxi and Guangdong ,and formed most speciees of Camellia

Key words: Camellia, Karyotype, Ploidy, Cytogeography