Cirsium vulgare (Savi) Ten.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Biennial weed 5–15 dm; stem conspicuously spiny- winged by the decurrent lf-bases, copiously spreading-hirsute to sometimes arachnoid; lvs strongly spiny, pinnatifid, the larger ones with the lobes again toothed or lobed, scabrous-hispid above, thinly white-tomentulose to sometimes green and merely hirsute beneath; heads several, purple; invol 2.5–4 cm, its bracts all spine-tipped, without any well developed glutinous dorsal ridge; achenes 3–4 mm; 2n=68. Pastures, fields, roadsides, and waste places; native of Eurasia, now widely established in N. Amer. June–Oct. (C. lanceolatum, misapplied)