The boreal Carex aquatilis was discovered nearly ten years ago in the Netherlands, in the provinces of Groningen and Drente (the northern part), in the north of this country. In the herbarium of the Royal Botanical Society of the Netherlands some older specimens from this area are preserved, erroneously identified by the collectors as C. acuta L. or C. gracilis Curt. (Kern and Reichgelt, 1947). The stations in the north of the Netherlands were the southernmost known. Outside the Netherlands the area of its distribution in Europe comprises Ireland, West and North England, Scotland, Iceland, Norway (to the south as far as near Oslo), Sweden (to the south it becomes rarer), Finland, Esthonia (near Reval) and North Russia (as far as Leningrad). Between the stations in the above-mentioned countries and those in the Netherlands a disjunction occurs, for C. aquatilis is not recorded from N.W. Germany and Denmark (Andreas, 1951). Because of the disjunct area and the occurrence of fossil remains in layers, belonging to the glacial period Miss Dr. Ch. H. Andreas (1951, 1953) considers" C. aquatilis in the Netherlands as a glacial relic.