This is an annual or short-lived perennial which grows in shallow water in marshes, ponds and ditches, and at the edge of slow-flowing streams and sheltered lakes. It occurs chiefly in water which is eutrophic and at least mildly base-rich, and is favoured by a degree of disturbance. Generally lowland, but reaching 445 m at Small Water (Cumberland).
The map of R. aquatilis in the 1962 Atlas included records of R. peltatus and R. penicillatus, as the taxonomy of these species was then unresolved. It is, therefore, difficult to assess changes in the distribution of the individual species.
European Temperate element; also in C. and E. Asia and western N. America.
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.