Centaurea nigra
L. Black KnapweedAscending, rhizomatous perennial to 1 m high. Basal leaves oblanceolate, to 25 cm long, 5 cm wide, entire to pinnatifid, acute, surfaces scabrous, margins undulate; cauline leaves lanceolate to oblong, 1–8 cm long, 2–10 mm wide, entire or sparsely toothed, acute, sometimes cobwebbed below, obscurely petiolate. Capitula solitary, broad-ovoid, 12–15 mm diam.; involucre 14–18 mm long; intermediate bracts ovate, glabrous, with a dark brown to blackish pectinate terminal appendage 2–4 mm long; inner involucral bracts longer but terminal appendage less deeply cut. Corolla 15–20 mm long, pale purple. Cypselas 3–4 mm long, pale brown, obscurely ribbed; pappus of bristles c. 1 mm long or absent. Flowers mainly spring and summer.
VVP, GipP, CVU, NIS, HSF, HNF, Strz. Also naturalised SA. Native to Europe. A declared noxious weed in Victoria where found sporadically on roadsides, in pasture and other disturbed sites.
Jeanes, J.A. (1999). Asteraceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 4, Cornaceae to Asteraceae, pp. 652–666. Inkata Press, Melbourne.