The bogs and broads situated in the NW corner of the province of Overijssel contain a rich desmid flora. Some species rare in or hitherto unrecorded for the Netherlands are discussed. The occurrence of a number of species with a predominantly arctic-alpine distribution, viz. of Cosmarium anceps, C. holmiense var. integrum, C. speciosum, and C. crenatum, is rather striking. These species live, in the area studied, atmophytically among bryophytic vegetation in mesotrophic quaking bogs. Also notable is the common occurrence of the not very well known species Cosmarium insigne in the tychoplankton of many lakes, particularly in those with well-developed stands of Stratiotes abides.