Most commonly found in still or slow-moving acid peaty waters, this species can be quite variable. It has stalked, floating, lanceolate-oval leaves which have opaque veins. It can also have submerged leaves with long stems and narrow blades. The flowers are very small, greenish with 4 tepals and 4 stamens and separate carpels. They are borne in spikes which emerge from the leaf axils and are held clear of the water. Some species have a flexible joint below the leaf but this species does not. They flower from May to September and are perennial natives, this species being widespread within its habitat. It belongs to the Potamogetonaceae family.
I first saw this species on the Inishowen peninsula in Co Donegal in late June, 2015 when I also photographed it.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre