Description from Flora of China
Carduus linearis Thunberg in Murray, Syst. Veg., ed. 14, 726. 1784; ?Cirsium hupehense Pampanini; C. lineare var. franchetii Kitamura; C. lineare var. latifolium H. C. Fu; C. lineare f. oreithales (Hance) Koyama; C. lineare f. pallidum Kitamura; C. lineare var. pallidum (Kitamura) Y. Ling; C. lineare var. salicifolium Y. Ling; C. lineare var. tsoongianum (Y. Ling) Y. Ling; C. oreithales Hance; C. tsoongianum Y. Ling; Cnicus linearis (Thunberg) Bentham & J. D. Hooker ex Franchet & Savatier; Spanioptilon lineare (Thunberg) Lessing.
Herbs (0.3-)0.6-1.5 m tall, perennial. Stems erect, branched from base or above, ribbed, unwinged, cobwebby and with long crispate hairs to glabrous. Leaves discolorous, abaxially grayish white and cobwebby, adaxially green, glabrous, with some crispate hairs, or ± densely covered with hair-tipped papillae and surface slightly rough but not spinulose. Lower and middle cauline leaves sessile or shortly petiolate; leaf blade ovate, lanceolate, elliptic, or oblanceolate, 6-18(-23) × 1.5-3(-5) cm, undivided or rarely with a few lobules or teeth in proximal third, base cuneate, margin ± regularly spinulose, apex obtuse to caudate-acuminate. Upper cauline leaves similar but always sessile, often narrower, gradually smaller upward. Capitula terminal, laxly corymbose, not surrounded with pectinately spiny pungent bracts. Involucre ± narrowly ovoid, 1-2.5 cm in diam., glabrous. Phyllaries imbricate, in ca. 6 rows, abaxially with a dark resinous gland; outer and middle phyllaries triangular-lanceolate, 5-8 × ca. 1 mm, tipped with a spinule to 2 mm; inner phyllaries triangular-lanceolate to linear, 10-15 × 1-3.5 mm, apically expanded into a scarious, acuminate, pale or purplish pink, and irregularly denticulate appendage. Florets bisexual. Corolla purplish red to pink, 2-2.2 cm, tube equaling limb. Achene ca. 2.5 mm. Pappus brownish to dirty white, ca. 1.5 cm. Fl. and fr. Aug-Oct.
Cirsium lineare is variable in leaf shape and papillosity as well as features of the involucre, but any attempt at subdividing it is premature. Cirsium hupehense is sometimes regarded as distinct; it was described with phyllaries ending in long, patent to recurved spines, a feature we have not observed in any of our material.
Mountain slopes, thickets, forest margins, grasslands, roadsides, wastelands, farmlands; 500-2500 m. S Anhui, Chongqing, Fujian, S Gansu, Guangdong, Guizhou, Hebei, Henan, Hubei, Hunan, NE Jiangxi, Shaanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, NE Thailand, Vietnam].