Sexual and agamospermous Taraxacum species in The Netherlands

A careful examination of 489 herbarium specimens of Dutch dandelions, identified by specialists and referred to 161 species of Taraxacum, strongly suggested that four of these taxa might by sexual diploids. The occurrence of diploid individuals of T. limburgense (sect. Vulgaria) was confirmed by chromosome counts. Facultative agamospermy may occur in 17 other species of that section. The specimens of the sections Erythrosperma. Obliqua, Palustria and Spectabilia studied did not indicate the incidence of sexuality or facultative agamospermy in these taxa in The Netherlands; as far as can be ascertained they are all triploid and agamospermous. The possible consequences of the occurrence of sexuality in connection with variation-patterns and processes of speciation within the genus Taraxacum in The Netherlands are concisely discussed.