The sterile hybrid Carex pseudocyperus L. X C. rostrata Stokes, new for the Netherlands, was discovered along a ditch near Gorredijk-Kortezwaag in the province of Friesland, in a large population of C. pseudocyperus. C. rostrata was found in the neighbourhood. The hybrid differs from C. pseudocyperus in, among other things, the glaucous leaves and the only slightly pendulous spikes. Compared with C. rostrata the hybrid has much flatter and wider leaves and the utricules gradually taper into the beak (fig. 2, a). The distinctly awned female glumes show the influence of C. pseudocyperus fig- 2,b).