Herbs to 1.7 m tall, perennial. Stems erect, branched above, ribbed, unwinged, with sparse multicellular hairs and cobwebby. Leaves concolorous, green, surface smooth, glabrous or with sparse multicellular hairs. Basal leaves present at anthesis. Lower and middle cauline leaves with winged petiole, base auriculate and semiamplexicaul, wing spiny or with spiny teeth; leaf blade elliptic, to 27 × 7 cm, pinnately divided; segments ca. 6 pairs, semiorbicular, ovate-lanceolate, or broadly triangular, margin spiny or with triangular teeth tipped with a 1-4 cm spine. Upper cauline leaves similar but sessile, lanceolate, gradually smaller upward, auriculate semiamplexicaul, margin with teeth ending in a 1-4 cm spine. Capitula few to many, laxly corymbose to corymbose-paniculate or rarely solitary, ± nodding. Involucre campanulate, 3-4.5 cm in diam., glabrous. Phyllaries imbricate, in ca. 7 rows, lacking an abaxial resinous gland, marginal spinules, wings, and scarious appendage; outer and middle phyllaries 0.7-1.5 cm × 1.5-2 mm, basal portion lanceolate, apical portion subulate, patent to reflexed, and narrowed into a short and soft spinule; inner phyllaries linear-subulate, ca. 18 × 1.5 mm, apex narrowed into a short soft spinule. Florets bisexual. Corolla purple, ca. 2.1 cm, tube ca. 1.2 cm. Achene brown, ca. 3.2 mm. Pappus bristles brownish, ca. 2 cm. Fl. and fr. May-Sep.
Home