100 Potamogeton pectinatus L.

This variable species has an almost world-wide distribution; see the marginal notes on the map. In Fennoscandia it occurs mostly in brackish sea water, otherwise generally in inland waters. It belongs to the circumpolar plants (Hultén, Circumpol. I, p. 128 and map 119). Cf. world map in Meusel et al. 1965, p. 25.