Abstract: The chromsomal number and karyotype of Cupressus gigantea Cheng et L. K. Fu is reported for the first time. The number of somatic chromosome in root tip cell of the species was found to be 2n=22. According to the terminology defined by Levan et al, the karyotype is 2n=22= 4m(SC)+16m+2sm, belonging to Stebbin's "A" type of karyotypic symmetry which is generally considered as primitive one. By comparing karyotypes of Cupressus gigantean with other four species of Cupressaceae, the author discovered that Cupressus gigantea is a primitive species in Cupressaceae.

Key words: Cupressus gigantea, Karyotype analyses