This variable perennial is found in relatively shallow water in a variety of water bodies, including lakes, reservoirs, rivers, streams, canals and ditches. It tolerates a wide range of water quality, although it is absent both from the most acidic and oligotrophic sites and from the most eutrophic. It survives occasional, short-term desiccation. 0?915 m (Meall nan Tarmachan, Mid Perth).
Like many aquatics, P. gramineus is better recorded than it was in the 1962 Atlas. However, it has declined in England since 1930 in areas where eutrophication and the conversion of grazing land to arable have reduced the number of suitable ditches.
Circumpolar Boreo-temperate element.
Perennation - primary
Life Form - primary
Clonality - primary
Clonality - secondary
Count of 10km squares in Great Britain: 473
Count of 10km squares in Ireland: 163
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: 0.67
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.