Francis, A., Darbyshire, S. J., Légère, A. and Simard, M.-J. 2012. The Biology of Canadian Weeds. 151.Erodium cicutarium(L.) L'Hér. ex Aiton. Can. J. Plant Sci. 92: 1359-1380. Stork's bill, Erodium cicutarium, is an annual weed of the geranium family (Geraniaceae), native to Mediterranean Europe, North Africa and western Asia. It has spread widely to temperate regions of both hemispheres, in particular to semi-arid ranges and prairies where it is frequently a dominant weed. In western Canada, it has increased in importance as a weed of cereal, canola, legume, sugarbeet and potato crops, particularly with the adoption of conservation tillage, and is both a field weed and seed contaminant of forage crops. The species had been sporadically collected in Québec since 1874 from cultivated fields (oats, potatoes, corn), but it recently appeared in experimental plots grown in corn, soybean, and red clover in eastern Québec, suggesting its potential as a serious weed. Outside of Canada, it is found in a range of crops, and has been host to viral, fungal and insect pathogens that can cause damage to crops and pastures. The plant's early germination, rapid growth and prolific seed production give it a competitive advantage in crops. In spring crops, the weed may be past the stage for optimal control by the time that the crop has reached the stage when herbicides are normally applied. Control may consequently require an extensive and often costly integrated weed management system. In semi-arid grazing areas it probably displaced some native vegetation, but has also become an important forage plant and a source of food for native wildlife. Its antioxidant and other chemical properties have drawn attention to potential medicinal and other beneficial uses.