A perennial herb of clear, oligotrophic water, only rarely extending into mesotrophic conditions. It is most frequent in upland lakes but also grows in pools, rivers, streams, canals and ditches. Many sites are exposed to strong winds, but it prefers water 0.3-1.5 m deep, away from the most exposed shallows. 0-1005 m (Beinn Heasgarnich, Mid Perth).
Because of taxonomic uncertainty, and its presence in areas which were poorly recorded, this species was seriously under-recorded in the 1962 Atlas. Some populations in N.E. Ireland and along the eastern edge of the Scottish range have been lost, possibly owing to eutrophication.
European Boreal-montane element; also in E. Asia and N. America.
Perennation - primary
Life Form - primary
Clonality - primary
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols,
, Königstein, (1986)
Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols,
, Jena, (1965)
Aquatic plants in Britain and Ireland,
, Colchester, (1997)