Stems glabrous or slightly tomentose. Leaves: basal wing-petioled, blades 15-60+ cm, margins coarsely lobed; cauline leaves clasping, progressively smaller and less divided, bases spiny, coiled, auriculate. Phyllary appendages spreading, ovate, 1-4 cm including long-tapered spine tips. Corollas 26-35 mm; tubes 13-25 mm, throats campanulate, 2-3 mm, lobes 5-9 mm. Cypselae brown and black spotted, 6-8 mm; pappus scales 15-20 mm. 2n = 34. Flowering Feb-Jun (west), Jul-Sep (north). Roadsides, pastures, waste areas; sometimes cultivated; 0-800 m; introduced; Alta., B.C., N.B., N.S., Ont., Que., Sask.; Ala., Ariz., Ark., Calif., Conn., Ind., La., Mich., Miss., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Oreg., Pa., Tenn., Tex., Vt., Va., Wash., W.Va.; s Europe (Mediterranean region). Silybum marianum is sometimes cultivated as an ornamental, a minor vegetable, or as a medicinal herb. Young shoots can be boiled and eaten like cabbage and young leaves can be added to salads. The seeds can be used as a coffee substitute. Extracts of S. marianum are used as an herbal treatment for liver ailments.

Plant: annual or biennial; stems 2-30 dm, glabrous or slightly woolly Leaves: alternate, dark green blotched white, ± glabrous; basal 15-60+ cm; petiole winged; cauline bases clasping, coiled, spiny INFLORESCENCE: heads discoid, large; peduncles bracted; body of heads 2-6 cm diam; involucre ovoid to spheric; phyllaries overlapping in several series, tips of outer and middle spreading, lanceolate to ovate, spiny-fringed and -tipped; receptacle flat, white-bristly Flowers: Flowers many; corollas pink to purple, tube long, slender, throat abruptly wider, lobes linear; anther bases sharply short-sagittate, tips oblong; style tip with slightly swollen node, appendage long, cylindric, branches very short Fruit: achenes, 6-8 mm, brown and black-spotted, ovoid, slightly compressed, glabrous, attachment slightly angled; pappus 15-20 mm, of many flat, minutely barbed bristles, falling in a ring Misc: Roadsides, pastures, waste areas; < 500 m. Notes: Leaf surface can be blotched with white.Leaf veins are usually whitish.Fruit usually brown with black spots.Pappus bristles spinulose-margined. References: Kearney & Peebles; Arizona Flora. Hickman, ed.; The Jepson Manual. ASU specimans