Abstract: This paper analyses the karyotypes of 12 species of Magnolia in China. x= 19. M. offcinalis, M. theinalis subsp. biloba, M. sp., M. delavayi, M. amoena and M. coco of them are diploid species, 2n=2x= 38; M. liliflora, M. denudata and M. biondii are tetraploid species, 2n= 4x= 76; M. lotungensis, M. grandiflora and M. grandthera var. lanceolota are hexaploid spe- cies, 2n=6x=114. The polyploidy (secondary polyploidy) exists in Magnolia. The result of karyotype analysis showes that the karyotype differences among species in Magnolla are very small. Most of chromosomes are metacentric (m) A few of them are submetacentric (sm). The diploid species have only a pair of acrocentric chromosome (st). All of them are 2B type.

Key words: Magnoliaceae