The present report deals with the dandelion flora of 78 lots of grassland from the coastal area and from the interior. It appeared that grassland types under the same agricultural management and with a similar phytosociological character also exhibit a similarity in their Taraxacum flora; when they differ in these respects they also have a different dandelion flora, which differences tend to increase as the vegetational and agricultural differences become greater. Several microspecies of the section Taraxacum may occur sympatrically in the same type of pasture, the stronger the manuring and grazing the greater the number of co-existing taxa (up to 19 per 125 m2 have been recorded). In near-natural dune habitats representatives of the sections Erythrosperma and Obliqua are the most common, in grazed ones the number of taxa belonging to these two sections tends to be lower. Representatives of the sections Palustria and Spectabilia have exclusively been found in unfertilized or but lightly fertilized grasslands and are now of rare occurrence. Those of sect. Taraxacum are very common and are frequently encountered in agricultural pasture land, the number of microspecies represented increasing as the agricultural pressure increases. It proved to be possible to distinguish within these sections microspecies with a broad ecological range and other ones with a much narrower amplitude, the latter apparently being more specialized ecologically. Among the Taraxacum microspecies those with a broad ecological tolerance find their optimum in the not strongly fertilized and grazed pastures and they may, therefore, be regarded as the older microspecies among the Dutch Taraxacum aggregate. The microspecies from heavily fertilized and grazed pastures must be considered to be specialized and apparently constitute the youngest among the complex.