Towards a revision of Taraxacum sect. Macrocornuta (Asteraceae, Crepidinae), an Irano-Turanian group with prevailing sexual reproduction

Taraxacum section Macrocornuta is widely distributed in the Irano-Turanian region, from Iran to NW. India and to Middle Asia. It is characterized by common sexual reproduction, unlike most of the other Taraxacum groups. More than 40 names were published referable or believed to refer to this group. A taxonomic and nomenclatural revision of these names was carried out on the basis of a detailed study of the original material of each name, and additional herbarium collections were consulted. Newly gathered material from expeditions to Iran and Kazakhstan was also evaluated. Four sexual species are recognized and accepted under previously published names (with nine synonyms), and one name based on sexually reproducing plant material remains to be studied. The variable complex around T. nevskii is divided into two subspecies (subsp. nevskii and subsp. lipskyi). As regards species with agamospermous reproduction, ten species were accepted, two of them are newly described (from Kazakhstan), another seven names were relegated to the synonymy. Four names, referable to T. sect. Macrocornuta, were left without taxonomic treatment (missing or totally inadequate original material), and seven names represent taxa excluded from T. sect. Macrocornuta. An identification key to all taxa is provided, together with typifications of names, and descriptions and comments for each species.