Coefficient of Conservatism:
Coefficient of Wetness:
Roadsides, railroads; a weed of cultivated fields and gardens; disturbed sites, including gravel pits, construction sites; disturbed deciduous forests, especially along trails and recent clearings; shores, marshy ground, river banks. Collected by the First Survey (1838) in Lenawee Co. and by 1888 collected in Keweenaw Co., so obviously long established in Michigan.
This species seems to set fruit well in this area, so the distinctive very compressed and smooth achenes are often available for positive identification. The large almost coiled auricles are often striking, especially as they, like the rest of the leaf margin, have prickles that tend to be longer, stiffer, and more numerous than in the other two species. Occasional plants with gland-tipped hairs as in S. arvensis var. arvensis may be called f. glandulosus Beckh.