A spring-germinating annual of light soils, found in arable and other cultivated ground including among horticultural crops, and in gardens and waste places. It reproduces by seed, but cold, wet summers inhibit its germination and growth. Lowland.
M. orontium has declined because of agricultural intensification and the more widespread autumn sowing of crops. Salisbury (1961) noted that it appeared to be less frequent than formerly, and since then it has declined sharply, disappearing from almost half of its 10-km squares in S.E. England in the last forty years.
As an archaeophyte M. orontium has a Eurosiberian Southern-temperate distribution; it is widely naturalised outside this range.
Light (Ellenberg): 7
Moisture (Ellenberg): 5
Reaction (Ellenberg): 6
Nitrogen (Ellenberg): 6
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4.3
July Mean Temperature (Celsius): 15.9
Annual Precipitation (mm): 864
Count of 10km squares in Great Britain: 488
Count of 10km squares in Ireland: 24
Count of 10km squares in the Channel Isles: 11
Atlas Change Index: -0.89
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
The Irish Red Data Book. 1. Vascular Plants,
, Dublin, (1988)
Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols,
, Königstein, (1986)
Vergleichende Chorologie der zentraleuropäischen Flora. Volume 2. 2 vols,
, Jena, (1978)
Britain’s arable weeds,
, British Wildlife, Volume 3, p.149-161, (1991)