Nucleotide characteristics, substitution pattern, secondary structure, and the phylogenetic utilitry of ITS2-5.8S-ITS2 from 301 clones of 32 species representing 11 sections of the genus Taraxacum were examined. The within-individual polymorphism of clones implies that the concerted evolution of ITS cistron of agamospermous polyploid Taraxacum is remarkably suppressed.