Cirsium heterophyllum

Perennial herb.

40–120 cm high.

The stem is erect, simple or few-branched, sturdy, sulcate, woolly and not alate or spinose like some other Cirsium species.

The leaf arrangement is spiral. The basal leaves are petiolate and can exceed 30 cm in length. The petiole is widely alate. The lamina is simple and entire. The stem leaves are amplexicaul. Tthe proximal stem leaves are pinnately lobed and the distal stem leaves are simple, densely dentate with sharp teeth. The lamina of all leaves is soft, lanceolate or ovate, acuminate, white-tomentose on the abaxial side white, and green and glabrous on the adaxial side.

The capitula are solitary or in small clusters of 2–4 at the summit of the stem. The capitulum is pedunculate, 3.5–5 cm long and up to 5 cm wide. The involucre is broad-ovoid with multiple rows of involucral bracts. The involucral bracts are erect, lanceolate, dark, cuspidate with a short soft cusp. The florets are bisexual, tubular, and typically purple or rarely white.

The achene is 3–5 mm long, slightly compressed at sides with a thickened annulus at the apex and a long-haired pappus (2–3 cm).