Desmids of the broads area of N.W.-Overijssel (The Netherlands) II

As a sequence to a previous instalment an annotated check-list of 245 desmid taxa recorded from the broads area of N W-Overijssel is concluded. The desmid flora of that area is characterised by the high rate of representation of mesotrophic species typical of rich fen habitats. The regular hemiatmophytic occurrence in wet Scorpidium cushions of a number of species with a predominantly arctic-alpine distribution is striking. The also diversified, tychoplanktonic desmid flora of the more eutrophic, peat excavated dikes and pools is seriously endangered as the result of water pollution.