Abstract: The number of somatic cell chromosomes,the size and density of stomata,the morphology and size of pollen grains and microsporocytes on "Guilin Liangfeng"Seedless Ponkan (Citrus reticulata Blanco)were identified.The results of cytological identifications showed the "Guilin Liangfeng"Seedless Ponkan was mixoploid(2n=2x=18 and 2n=4x=36)and its somatic cell ratio of 4x to 2x was 1:1,and the phenomenon was reported in Ponkan for the first time.Therefore, it is a new type mutant of seedless and may be used as the germplasm resources in citrus breeding.