DISTRIBUTION OF C(3) AND C(4) SPECIES OF CYPERUS IN EUROPE

A complete survey is presented of photosynthetic pathway in the 27 spe cies of the genus Cyperus occurring in Europe. Among them, there are 2 0 species with C4 photosynthesis and 7 species with C3 photosynthesis. In 14 species the pathway is reported for the first time. With differ ent patterns, both C3 and C4 types occur from the Mediterranean region (35-degrees-N) to the cool temperate region (52-degrees-N). Atlantic current may have a striking effect on the distribution of wetland C4 s edges. Although the existence of rhizomes in C4 Cyperus perennials fav ours their survival at short summers of central and west Europe, low t emperature at late summer in the regions prevents them to complete see d development. Leaf anatomy indicates that dry summer in Mediterranean regions limits some of them due to their lavish water requirement. In the eastern and north Europe a long period of low temperature in wint er may be the most important reason for the absence Of C4 Cyperus spec ies.