Abstract:Root-tip metaphase chromosome numbers of 6 taxa of Hibiscus were investigated by wall degradation hypotonic staining method. Chromosome numbers for H. schizopetalus (Masters) Hook.f.(2n=42), H. mutabilis L.(2n=92), H. rosa-sinensis L.(2n=84), H. rosa-sinensis cv. Double Rainbow (2n=105), H. rosa-sinensis cv. Flavo-plenus (2n=138) and H. rosa-sinensis cv. Carminatus (2n=147) arereported. It is shown that the ploidy relationship exists among them except cv. Flavo-plenus, the basic chromosome number being x=21. From the observation on chromosome numbers and morphological characters， H H. rosa-sinensis L. is thought to be a hybrid which arose from cv．Carminatus and H. schizopetalus．