5. Cirsium kamtschaticum Ledebour ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 644. 1838.
Perennials, 25–200 cm; rhizomes stout. Stems single, erect, ± glabrous to variably tomentose with coarse, jointed, multicellular trichomes and/or fine smooth trichomes; branches 0–few, ascending. Leaves: blades broadly elliptic to obovate, 15–40 × 7–15 cm, subentire to coarsely pinnatifid 1/2–2/3 length to midveins, lobes few, lanceolate to triangular-ovate, shallowly lobed or dentate, main spines bristlelike, fine, innocuous, 3–6 mm, abaxial glabrous to villous with septate trichomes or thinly tomentose with jointed trichomes, adaxial faces glabrous or loosely tomentose along midveins; basal usually absent at flowering, winged-petiolate, ciliate with fine, flexible spines to 8 mm; principal cauline well distributed. little reduced, bases broadly tapered to clasping, short-decurrent; distalmost moderately reduced. Heads 1–few, in spiciform or subcapitate arrays. Peduncles 0–1 cm. Involucres hemispheric to broadly campanulate, 1.5–2 × 2–3.5 cm, ± densely arachnoid. Phyllaries in 5–7 series, subequal, green or tinged purple, linear or linear-lanceolate, abaxial faces without glutinous ridge, outer and middle erect or outer spreading, entire, apices long-acuminate, spines 0–2 mm; apices of inner phyllaries straight or flexuous, flat. Corollas pink to purple, 16–17 mm, tubes 8–9 mm, throats 3–4 mm, lobes 4–5 mm. Style tips 3–4 mm. Cypselae brown, 4 mm, apical collars not well differentiated; pappi 12–15 mm. 2n = 68 (Japan).
Flowering summer (Jul–Sep). Meadows and tundra; 0–100 m; Alaska; Asia (Japan, Siberia).
Cirsium kamtschaticum grows in the western Aleutian Islands, eastern Siberia, Sahkalin, the Kurile Islands and northern Japan (Hokkaido). It is one of only two species of the genus that have native populations in the Old World and the flora area. Neither reaches the North American mainland.