Coefficient of Conservatism:
Coefficient of Wetness:
A. A. Reznicek
A persistent weed of yards and gardens, cultivated fields, city streets, parking areas, hedges, foundations of buildings, railroad yards, bulldozed land, and disturbed places generally. Michigan records go back at least to 1877, with a fragmentary specimen probably this species from 1846 (Macomb Co.).
Specimens of this species with the largest involucres and those of S. arvensis with the smallest involucres are sometimes hard to assign, especially if underground parts and ligule shade are not observed or recorded on the label. The often large and ± acute auricles on the leaves of S. oleraceus may help; in S. arvensis the auricles run smaller and are rounded (and are also usually smaller and less prickly than in well developed S. asper).