A rhizomatous perennial of oligotrophic to mesotrophic habitats, usually growing on peat. It is found in swamps at the margins of lakes and ponds and along streams, and in tall-herb fens and open fen carr. In England and Wales it is largely restricted to calcareous sites, whereas in the Hebrides and W. Ireland it also occurs in acidic areas. Lowland.
C. mariscus has declined because of drainage, and some lowland sites are currently threatened by eutrophication and scrub invasion. However, it was under-recorded in Scotland in the 1962 Atlas, and new sites may await discovery there.
Eurosiberian Southern-temperate element; also in N. America.
Height (cm): 200
Perennation - primary
Life Form - primary
Life Form - secondary
Comment on Life Form
Clonality - primary
Count of 10km squares in Great Britain: 232
Count of 10km squares in Ireland: 258
Count of 10km squares in the Channel Isles: 1
Atlas Change Index: 0.11
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
1942. Biological Flora of the British Isles. No. 6. Cladium mariscus (L.) R. Br. Journal of Ecology. 30:211-216.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1997. Aquatic plants in Britain and Ireland.