259 Catabrosa aquatica (L.) Beauv.

This polymorphic species is widely distributed in Europe and partly Asia and N. America. Two lower taxa are described from N. America, viz. var. laurentiana Fern. and var. uniflora S. F. Gray (also in Europe). The species is reported among the amphiatlantic plants (Hultén, Amphi-atl., p. 70 and map 52), although it has a wider distribution. It has been reported from southernmost S. America.