Mountain or alpine thistle

Cnicus eriocephalus A. Gray, Proc. Amer. Acad. Arts 10: 46. 1874, based on Cirsium eriocephalum A. Gray, Proc. Acad. Nat. Sci. Philadelphia 15: 69. 1864, not Wallroth 1841; Carduus hookerianus Nuttall var. eriocephalus (A. Gray) A. Nelson; Cirsium scopulorum (Greene) Cockerell ex Daniels

Stems erect or ascending, 30–150 cm. Leaf faces thinly to densely arachnoid-tomentose, especially abaxially, and villous or tomentose with septate trichomes, especially along midveins, adaxially ± glabrate. Heads sessile or short-pedunculate in usually nodding, densely woolly-tomentose, spiciform or racemiform arrays. Involucres 2.5–3.5 cm, densely tomentose with septate trichomes (individual phyllaries obscured by tomentum). Phyllaries: outer with stiff lateral spines; apical spines slender. Corollas yellow (northern populations) or pink to pale purple (southern populations), 13–18 mm, tubes 6–9 mm, throats 3–5.5 mm, lobes 3–7 mm. Pappi 10–15 mm. 2n = 34 (as C. scopulorum).

Flowering summer (Jul–Sep). Forest openings, alpine and subalpine meadows, windswept alpine ridges; 2200–3800 m; Colo., N.Mex., Utah.