116 Potamogeton lucens L.

This rather variable species is widely distributed in Eurasia. The distribution in Siberia is still uncertain. Hybrids with related species are fairly common. P. lucens and the closely related N. American P. illinoensis Morong together show an amphi-atlantic distribution pattern (Hultén, Amphi-atl., p. 72 and map 53). Cf. also Meusel et al. 1965, map p. 24.