Abstract: Both the shrinkage of ancient Mediterranean Sea and the ridge between the Himalayas－Hengduan mountain have an important effect on the development of the flora of the Malus Mill. The origin and development of the flora of the Malus Mill. in Hengduanshan mountain were discussed with the theories and methods of systematics and phytogeography. The result indicated that the small fruit types of M.laosensis Chev. was transmitted to Hengduan mountainous district from the southern part of Yunnan by river valley. During this process, Ser. yunnanense Rehd. was evolved from permanent calyx, and Ser. kansuensis(Batal.)Schneid. was evolved from decalyx , too. The evolving features of the flora of the Malus Mill. in Hengduan mountain were: (1) the long-lasting history; (2) the many types; and (3) the differential among types. Furthermore, the flora of the Malus Mill. in Hengduan mountain which had the distinctive evolution center and the radiating distribution, demonstrates the flora of the genus Malus Mill. in Hengduan mountainous region had a rich types, but it is not the area where origin species don't appear. So it is an evolution center of the Malus Mill., not an origin center.

Key words: Malus Mill., Flora, Introgressive hybridization, Origin center, Evolution center, Hengduan mountains district