AbstractElectrophoretic data were used to assess levels of clonal diversity within and among populations ofTaraxacum albidumDahlst., a pentaploid obligate agamosperm indigenous to Japan. All specimens sampled from the entire distribution range shared the same 19‐locus genotypic profile except for one. This single mutant differed in one allele at one locus only. Contrary to this extreme monomorphism, clonally reproducing species usually consist of multiclonal populations. It is hypothesized thatT. albidumrecently originated through hybridization between a sexual diploid species of the section Mongolica (most likelyT. japonicumKoidz.) and an unknown polyploid Mongolica specie