Some species, especially in ponds and very slow-moving waters, have floating leaves which tend to be opaque with a leathery texture.

Leaf shape has been found to be highly plastic, with variability due to changes in light, water chemistry, planting depth, sediment conditions, temperature, photo period, waves, and seasonality.

Series Batrachoseris historically contained only one species, Potamogeton crispus,[11] however more recent research has also added P. maackianus and P. robbinsii into this grouping.

[7] These general divisions have been supported by molecular analysis, except that P. crispus clusters with broad-leaved species in section Potamogeton.

However, the greatest diversity of species occurs in the northern hemisphere, especially in North America, which is thought to be where the genus originated.

[12] However, due to their self-propagation from turions, Potamogeton populations show very low infrapopulation diversity,[15] especially when living in deep, shaded or turbulent water where colonies do not expend energy on flowers.

His death intervened, and the work was completed by Arthur Bennett (1843-1929), who named a large number of specimens sent to him from around the world.

Robert Morgan (1863-1900) illustrated Fryer's contribution to the monograph, his colour plates drawing praise from later critics.

[20][21] In 1916, Johan Hagström published Critical researches on the Potamogetons from detailed measurements of dozens of vegetative, anatomical and reproductive characteristics such as fruit beak, peduncle rigidity and leaf apex across hundreds of specimens.

[22] It was a pioneering work that preceded the development of cladistics by more than 30 years,[23] and his clustering of groups into broad-leaf and linear-leaf is still considered the framework for all subsequent classification systems of Potamogeton.

Vegetative propagation occurs by a variety of mechanisms including turions, and via growth and fragmentation of rhizomes and shoots.

Vegetative reproduction is evidently an effective means of ensuring local persistence, as sterile hybrids have been recorded at some sites for over 100 years.

Although they occur in a range of environments, most species prefer standing or slow-flowing waters with some calcium and fairly low nutrient levels.

[27][28] They are important as food and habitat for animals including insect larvae, water snails, ducks and other waterfowl, and aquatic mammals such as beavers.