The majority of Taraxacum species are obligate agamospermous plants and polyploid. Diploid sexual species are frequent in parts of Asia and south-east Europe, and have also been found locally in northern Europe, in Greenland and in the Falkland Islands

SUMMARY Results of hybridization experiments between twenty-six species of Taraxacum (nine of which are sexual) are reported. Most crosses set good seed. The chief barriers to interspecific hybridization seem to be absence of sexuality, absence of pollen and restitutional pollen. There is no evidence of seed-incompatibility. Taxonomically remote hybrids set less good seed than near interspecific hybrids. Hybrids are intermediate in character and usually more vigorous than the parents. The progeny of diploid sexual males are fertile, diploid and sexual, those of triploid agamospermous males are mostly near-diploid, fertile and sexual, but some are facultatively agamospermous triploids. The existence of several intraspecific character differences is noted in some sexual species and the nature of character inheritance is noted in interspecific hybrids. The nature of hybrids in the field is discussed and examples of hybrid populations reported. The scarcity of reports of hybrids is noted and reasons for this are discussed.