), P. coloratus (P. × billupsii Fryer), P. maackianus (P. × biwaensis Miki), P. illinoensis (P. × spathuliformis (J.W.Robbins) Morong), P. richardsonii (P. × hagstromii A.Benn.

However, due to its highly variable nature and propensity for hybridisation, various-leaved pondweed has received a bewildering number of synonyms.

[citation needed] DNA analysis indicates that P. gramineus is one of the broad-leaved pondweed clade (section Potamogeton) and is probably most closely related to the P. lucens group.

It occurs in northern Europe (Britain,[4] Ireland, Iceland, Scandinavia, Germany, Switzerland, France, Poland, Russia, the Baltic States),[7][8] Greenland, North America (US except for the southeast, Canada).

[7][9] There are outlying populations in southern Europe (Iberia, Corsica, Italy), Caucasus, Pyrenees and western US.

[7] Various-leaved pondweed grows in various water body types including ponds, lakes, bogs, ditches and streams.

In Sentiz Lake (Leon, Spain), P. gramineus was sparse and the dominant plants were Ceratophyllum demersum and Myriophyllum spicatum.

[9] Indices of environmental tolerance using trophic ranking schemes in Europe tend to show P. gramineus to be one of the more nutrient-sensitive aquatic plants.

[26] However, in Britain P. gramineus also occurs in waters with lower nutrient concentrations and is considered a characteristic species of mesotrophic lakes.

In common with other pondweeds of this group it roots poorly from stem cuttings and is best propagated by division of the rhizomes.