Centaurea ×moncktonii

Ascending, rhizomatous perennial to 1.5 m high. Basal leaves oblanceolate or elliptic, to 25 cm long, 4 cm wide, entire to pinnatifid, acute, surfaces pubescent to scabrous, petiolate; cauline leaves linear to lanceolate, 1–8 cm long, 2–10 mm wide, entire or sparsely toothed, acute, sessile. Capitula solitary, broad ovoid, 15–18 mm diam.; involucre 12–18 mm long; intermediate involucral bracts ovate to lanceolate, tomentose to glabrous, with a light to dark brown, pectinate, terminal appendage 4–5 mm long; inner involucral bracts longer with lacerate terminal appendages. Corolla 15–20 mm long, purple (rarely white in overseas material). Cypselas 2.5–3 mm long, pale brown or grey, obscurely ribbed; pappus of bristles c. 1 mm long or absent.    Flowers late spring to autumn.