A complete survey is presented of photosynthetic patfaway in the 27 species of the genus Cyperus occurring in Europe. Among them, tíiere are 20 species vsdth C4 photosynthesis and 7 species with C3 photosynthesis. In 14 species the pathway is repoited for the first time. Wifli different pattems, both C3 and C4 types occur from the Mediterranean region (35 °N) to the cool temperate region (52 “N). Atlantic current may háve a striking effect on the distňbution of wetland C4 sedges. Although the existence of rhizomes in C4 Cyperus perennials favours their survival at short summers of centra! and west Europe, low temperature at latě summer in the regions prevents them to complete seed development. Leaf anatomy indicates that diy summer in Mediterranean regions limits some of them due to dieir lavish water requirement. In the eastem and north Europe a long period of low temperature in winter may be the most important reason for the absence of C4 Cyperus species.