An erect annual of well-drained, open habitats such as pavements, waste places, walls, railway ballast and as a weed of cultivated ground. It is particularly characteristic of urban areas of S. and E. England. It also occurs occasionally on sand dunes and on sandy ground inland. Lowland.
This species has been known in the London area since 1690. It has shown a marked expansion of range in Britain since the 1962 Atlas, and was first recorded in Ireland in 1983.
Native of N. America; naturalised throughout Europe and in similar climatic regions almost worldwide.
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
Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols,
, Königstein, (1986)
Vergleichende Chorologie der zentraleuropäischen Flora. Volume 3. 2 vols,
, Jena, (1992)