Description from Flora of China
Herbs (10-)20-100 cm tall, biennial or perennial. Stem solitary, long branched, ± hirsute; wings toothed, teeth with major spines pungent, 3-5 mm. Leaves concolorous, light or bluish green, not or scarcely cobwebby, sparsely hirsute along veins. Basal and lower cauline leaves sessile, elliptic to oblanceolate, 6-29 × 2-7 cm, pinnately lobed to pinnatipartite; segments 6-12 pairs, elliptic to triangular, margin toothed, teeth laterally and apically with 3-5 mm spines. Middle and upper cauline leaves similar but gradually smaller upward; uppermost cauline leaves ± broadly linear, sometimes undivided. Capitula mostly solitary or clustered at end of stem and branches. Involucre subglobose, 1.5-2(-2.5) cm in diam., glabrous or sparsely cobwebby. Outer phyllaries linear to triangular-subulate, ca. 7 × 1 mm, apical spinule 1-2 mm; middle phyllaries 8-14 × 1.5-1.6 mm, narrowed into a triangular-subulate erect-patent or spreading distal portion with apical 1-2 mm spinule; inner phyllaries linear, straight, ca. 16 × 1 mm, apex thin and acuminate. Corolla purplish red or rarely white, ca. 1.7 cm, tube ca. 8 mm. Achene brownish, ca. 4 mm. Pappus bristles white, ca. 1.5 cm. Fl. and fr. May-Oct. 2n = 16, 22.
The distinction between Carduus crispus and C. acanthoides breaks down in Chinese material, which for the most part shows intermediate features. Perhaps only a single species (best assigned to C. acanthoides) exists in China.
Carduus acanthoides is naturalized in North and South America and the Pacific islands (New Zealand).
Mountain slopes, mountain valleys, ravines, grasslands, forest margins, thickets, farmlands, by water; 200-3500 m. Gansu, Guizhou, Hebei, Henan, SW Hunan, W Jiangsu, N Jiangxi, S Nei Mongol, Ningxia, E and S Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, N Xinjiang, E Xizang, Yunnan [Russia; SW Asia, Europe].