Abstract: The chromosome number and size of two intergeneric hybridized combinations between Magnolia and Michelia in Magnoliaceae were studied in this paper. Magnolia liliflora is a tetraploid species with a chromosome number of 2n = 4x = 76 , Michelia yunnanensis is diploid species with a chromosome number of 2n = 2x = 38.The intergeneric hybridized combination , Magnolia liliflora ( ♀) ×Michelia yunnanensis ( ♂) , is triploid with a chromosome number of 2n = 3x = 57 , which was a half of the total chromosome number of its two parents. Of
which , 38 chromosomes from M. liliflora are smaller , and 19 chromosomes from M. yunnanensis are larger.So , the hybrid was confirmed to be crossbreeding filial generation of M. liliflora and M. yunnanensis. Michelia sphaerantha is a diploid species with a chromosome number of 2n = 2x = 38. Magnolia grandiflora is a hexaploid species with a chromosome number of 2n = 6x = 114. The intergeneric hybridized combination , M. sphaerantha ( ♀) ×M. grandiflora ( ♂) , is a diploid with a chromosome number of 2n = 2x = 38 , which is the same to that of its female parent , M. sphaerantha , in number and size. So , the hybridized combination is not a real hybrid , and the filial generation may be resulted from apomixes. The study showed that cytological method is one of efficient measures applied to early identification in crossbreeding of Magnoliaceae. The cross - compatibility indicated that Michelia is closely allied with Magnolia subgenus Yulania and is far allied with Magnolia subgenus Magnolia in phylogeny.

Key words: Magnolia , Michelia, Hybridized combination, Chromosome