A small annual or short-lived perennial, found at the edge of small water bodies and by the sheltered backwaters of rivers. It often grows on the cattle-poached edges of ponds, ditches and streams, in wet gateways and on paths and tracks. It tolerates a broad range of pH and nutrient levels, including nitrophilous conditions. 0-770 m (Little Dun Fell, Westmorland).
This species was lost from some sites in S.E. England before 1900 as a result of agricultural improvement and urban spread. It has declined since 1950 in areas where the agriculture is now mostly arable, but remains frequent elsewhere.
Suboceanic Southern-temperate element.
Light (Ellenberg): 7
Moisture (Ellenberg): 10
Reaction (Ellenberg): 5
Nitrogen (Ellenberg): 5
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.6
July Mean Temperature (Celsius): 14.5
Annual Precipitation (mm): 1093
Height (cm): 9
Perennation - primary
Perennation - secondary
Life Form - primary
Life Form - secondary
Comment on Life Form
Clonality - primary
Clonality - secondary
Count of 10km squares in Great Britain: 1703
Count of 10km squares in Ireland: 551
Count of 10km squares in the Channel Isles: 8
Atlas Change Index: 0.1
Weighted Changed Factor: -17
Weighted Change Factor Confidence (90%)
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1989)
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1997. Aquatic plants in Britain and Ireland.