Abstract: A karyomorphological study of the monotypic genus of Sladenia is studied and compared with those of the supposedly related families, such as Actinidiaceae, Theaceae sensu stricto, and Ternstroemi-aceae. It confirms that chromosome number of Sladenia is 2n = 48. Sladenm has 2A karyotpye with a kaiyotypic formula of 2n = 4x = 48 = 4M + 36m + 8sm. Its interphase nucleus is characteristic of densely diffuse type. The condensation behavior of chromosomes during mitotic prophase conforms to the interstitial type. Comparative kaiyotype reveals that Sladenia is different from the related families not only in the ba-sic number, but also in the size and morphology of metaphase chromosomes, the structure of interphase nuclei, condensation behavior of chromosomes during mitotic prophase, and presence or absence of the satellite and the nucleolar organizing region as well as. These dissimilarities indicate that Sladenia is far from Actinidiaceae, TTieaceae sensu stricto. Moreover, the karyomorpholgical study shows that SMenia is not close to Temstroemiaceae, which was achieved by the previously molecular data.

Key words: Sladenia