The floating leaves are opaque, 40–105 × 15–70 mm, usually brownish or dark green in colour with a pink tint when young, with inconspicuous secondary veins.

It is more localised in the rest of its range including Northern Iberia, Germany, mainland Italy, Sicily, southern Scandinavia, the Baltic states, the Balkans and eastern Europe.

[2] There are outlying populations in North Africa (Morocco, Algeria), Orkney, Shetland, the Faroes and Newfoundland, and fossils have been found in Russia.

[3] In Britain and Ireland, this is one of the commonest pondweeds, occurring in almost any wet or semi-wet oligotrophic and acidic habitat so long as flow is not too rapid.

In British rivers it typically grows with other soft-water species such as Ranunculus flammula, Carex nigra, C. rostrata, Scapania undulata and Equisetum fluviatile.

[5] In lakes it tends to occur in base-poor, oligotrophic waters with species such as Littorella uniflora, Sphagnum spp., Lobelia dortmanna and Isoetes lacustris[6] especially with a peaty substrate.

[9] In Central Europe, Potamogeton polygonifolius is threatened, and is considered endangered in Germany, Poland, Switzerland, the Czech Republic.