A rhizomatous perennial herb growing at the margins of streams, canals, ponds and lakes in shallow, nutrient-rich calcareous water. The European plant is a sterile triploid. Lowland.
A. calamus was introduced into England in the 16th century and by 1668 was established in the wild. It appears to be more widespread than when mapped in the 1962 Atlas, probably due to better recording as the plant flowers shyly in our area and may well have been overlooked in the past.
Native plants are diploid (Siberia, N. America) or tetraploid (S. & E. Asia); the origin of the triploid is unknown but it is naturalised in Europe & W. Asia, the Himalayas and eastern 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.