Annual or biennial. Stem erect, branching above, finely grooved, with patent pale spines up to 4 mm long, especially below, (50)-100-280 cm tall. Lvs green; rosette and lower stem lvs tapering to base, with spinous bristles beneath on midrib and often on secondary veins, 8-25-(35) × 5-18 cm, deeply runcinate-pinnatifid to undivided; margins dentate to bristly-ciliate, usually sinuate. Upper lvs often with spinous bristles on midrib, oblong to obovate, often triangularly 3-lobed at apex, with oblong to rounded amplexicaul auricles at base. Infl. diffusely paniculate. Capitula numerous, cylindric. Involucre (11)-13-15 mm long; bracts imbricate, suberect to reflexed at fruiting; outermost bracts ovate to lanceolate, subacute, ?-1/2length of innermost bracts; inner bracts lanceolate to linear, subacute. Florets c. 11/2× length of involucre; corollas erect to erecto-patent, yellow. Achenes very dark brown or black, 5-8-ribbed on each face, obovate, flattened, finely spiny distally on ribs; body 4-5 mm long; beak pale, c. = body. Pappus fine, white.