1350 Trapa natans L.

This rather warmth-demanding water plant is nowadays restricted to C., E. and S. Europe but occurs also in C., W. and SW. Africa. During the hypsithermal period, i. e. the postglacial warmth period (ca. 6.500-500 B.C.), it had a larger distribution towards the north, approximately to the braken line on the map. Up to rather recent times it occured in S. Sweden (circles). It is introduced and naturalized in eastern N. America. The closely related T. longicornis Vassil. occurs in C. Asia. Cf. also world map in Meusel et al. 1978, p. 301.