Peduncles stipitate-glandular. Phyllaries stipitate-glandular, longer 14-17 mm. 2n = 54.

Flowering Jul-Sep. Disturbed sites, mostly wet, particularly in urban areas, roadside ditches, along streams; 0-1600. m; introduced; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask.; Alaska, Calif., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nev., N.H., N.J., N.Y., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Utah, Vt., Wash., Wis., Wyo.; Europe; widely introduced elsewhere.

Subspecies arvensis is considered a noxious weed in California, Idaho, Illinois, Iowa, Maryland, Minnesota, Nevada, North Dakota, South Dakota, and Wyoming.

From Flora of Indiana (1940) by Charles C. Deam

Frequent along U. S. Highway 12 south of Buffington, about 2 miles southeast of Indiana Harbor, Lake County. There is also a large colony along the Lake Erie Railroad just south of Bluffton, Wells County. If left undisturbed this species and its variety spread rapidly.

……

Indiana Coefficient of Conservatism: C = null, non-native

Wetland Indicator Status: FACU