An annual or biennial herb, sensitive to grazing, occurring as a native on coastal cliffs, inland rock outcrops and perhaps sand dunes, but much more widespread as a plant of rank calcareous grassland, woodland margins, road-banks, quarries, tracks and rough ground. Lowland.
L. virosa was first recorded in Britain in 1570 but it was often recorded in error for L. serriola forma integrifolia before 1930, so it may have been rarer then than records suggest. Road development has greatly assisted its spread since 1980. Recorders have not distinguished the alien sites and all records are therefore mapped as if they are native.
Suboceanic Southern-temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 4
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 7
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.6
July Mean Temperature (Celsius): 16
Annual Precipitation (mm): 693
Height (cm): 200
Perennation - primary
Perennation - secondary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 650
Count of 10km squares in Ireland: 3
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: 1.16
Weighted Changed Factor: 66
Weighted Change Factor Confidence (90%)
Atlas text references
1984. The comparative ecology of two sand dune biennials: Lactuca virosa L. & Cynoglossum officinale L. New Phytologist. 96:609-629.
1992. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 3. 2 vols.
2000. Historical records of Lactuca serriola L. and L. virosa L. in Britain, with special reference to Cambridgeshire (v.c. 29). Watsonia. 23:149-159.
1953. A changing flora as shown in the study of weeds of arable land and waste places. The changing flora of Britain. :130-139.