EN
Distribution of 18S-26S rDNA on the chromosomes of Dendranthema nankingense and its two close-related species D. nankingense and D. lavendulifolium was studied by fluorescent in situ hybridization with a JHD 2-15A DNA clone: Six rDNA loci were found in D. nankingense, eight in D. lavendulifolium, and twelve in D. indicum. The rDNA loci number and pattern were applied to analyze the phylogenetic relationship of the three closely related species.