Abstract:The karyotypes of three hybrids and their parents in Magnoliaceae were studied. Their karyotype formulae are as follows: 2n=2x=38=36m+2sm for Michelia yunnanensis, 2n=2x=38=34m+4sm for Michelia calcicola and 2n=2x=38=26m+12sm for their hybrid A; 2n=2x=38=32m+6sm for Michelia crassipes and 2n=2x=38=24m+12sm+2st for hybrid C from Michelia crassipes and Michelia yunnanensis; 2n=2x=38=28m+10sm for Magnolia delavayi, 2n=6x=114=88m+10sm+16st for Magnolia grandiflora and 2n=4x=76=57m+15sm+4st for their hybrid U. The results showed that the karyotypes of these hybrids were markedly different from the expected ones according to the parental karyotypes, which might result from the structural variation of the parental chromosome during the hybridization. Therefore, it is difficult to identify these hybrids by the karyomorphological characters.