Using nucleotide-specific agents Hoechst 33258, actinomycin D, chromomycin A3, and distamycin A, the Paris quadrifolia L. karyotype, and the location and nucleotide composition of heterochromatic bands were studied. The chromosome ideogram of H33258/AMD and CMA/DA heterochromatic bands was created by an image analysis system with the Videotest-Kario software. By fluorescence in situ hybridization, the 18S and 26S rRNA genes were mapped.