Erect or ascending rhizomatous, colony-forming perennial herb to c. 2 m tall; stem striate, mostly unbranched, glabrous, gland-dotted, resinous. Leaves petiolate, lanceolate, 50–130 mm long, 8–30 mm wide, entire or denticulate, glabrous, black gland-dotted, acute to acuminate at apex. Capitula in dense, terminal corymbs; involucre hemispherical, those of male capitula 3.5–5 mm long, those of female capitula 3.8–4.8(–6) mm long; involucral bracts narrowly lanceolate, 2–4 mm long, glabrous, gland-dotted, resinous, inner series ± equal; margins erose or ciliate. Male florets 26–40; corollas 3.5–4 mm long (based on non-Australian plants). Female florets 80–150; corollas 1.7–3 mm long. Cypselas obovoid, sometimes curved, 0.6–1.5 mm long, light-brown, 5-nerved, glandular, hispidulous at apex (based on non-Australian plants); pappus 2.6–4(–7) mm long. Flowers spring–autumn.
