This submerged aquatic plant has very flattened, branching stems that can reach up to 0.9 m in length (5). The leaves are long and slender; they usually have five main veins running along their length, and are translucent (1). The small flowers are produced sparingly (2) on spikes (3). The Latin name Potamogeton derives from the Greek for 'river neighbour' and indicates the aquatic habits of this genus of plants (3).
This nationally scarce species has suffered a prolonged decline in the UK (2). At present it occurs in scattered sites in central England, coastal areas of Norfolk, the Welsh borders and a single site in Scotland (6). It is widespread in temperate Eurasia (7).
Occurs in the euphotic layer of either still or gently flowing water and has been recorded in a variety of aquatic habitats including rivers, ox-bow lakes, canals, lakes in low-lying areas and ditches (2).
A number of threats to this species have been identified, including eutrophication (nutrient enrichment) of the water bodies it inhabits, recreational pressures such as boating and the resulting pollution and churning up of the sediment, as well as the neglect of canals and ditches (2).
Grass-wrack pondweed is a UK Biodiversity Action Plan priority species, and a Species Action Plan has been produced to guide its conservation. The action plan aims to maintain and enhance the current UK range of the species and encourage it to spread to new sites (2). In addition, a programme of research has been proposed to investigate the requirements of this plant and ways to conserve it (2).
The UK Biodiversity Action Plan for this species is available at UK BAP.
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