Abstract: Karyotypes of 12 species of Michelia in the Magnoliaceae were studied. Theirkaryotype formulas are: M. macclurei var. sublanea 2n＝34m(2SAT)+4sm; M. alba 2n＝34m+4sm; M. floribunda 2n=30m+8sm; M. champaca 2n=32m+6sm; M. shiluensis 2n=32m+6sm; M. platypetala 2n=32m+6sm(2SAT); M. figo 2n＝32m+6sm; M. maudiae 2n=32m+6sm; M. longistamina 2n＝32m+6sm; M. foveolata 2n＝34m+4sm; M. skineriana 2n=30m+8sm; M. wilsonii 2n＝30m+8sm(2SAT). All the species are of the symmetrical karyotype. The karyotypes all belong to 2A type except that of M. floribunda which is of 1A type. Due to the karyotype similarity among species, the karyotype data in Michelia may be hardly useful for infrageneric taxonomy.

Key words: Michelia, Karyotype analysis