Erect, strongly aromatic annual to 1(–2) m high. Leaves pinnate, 3–15 cm long; leaflets 3–11, narrow-elliptic to linear, mostly 2–8 cm long and 2–10 mm wide, acute, dentate, glabrous, glandular. Capitula many, cylindric, 2–5 mm diam.; involucral bracts 3 or 4, fused into a tube, 9–11 mm long, glabrous, covered with elongate orange glands, free part c. 0.5 mm long, rounded, ciliate. Florets pubescent below, c. as long as involucre; ray florets 2–4, ligule 1–3 mm long, yellow; disc florets 4 or 5, greenish. Cypselas linear, 6–8 mm long, appressed-pubescent, black; pappus of 5 or 6 lanceolate scales, c. 0.5 mm long, scarious, margins ciliate, at least 1 produced into an awn to 3.5 mm long Flowers Feb.–July.
MuM, RobP, CVU, EGU, HSF, HNF. Also naturalised WA, SA, Qld, NSW. Native to South America. A widespread but uncommon weed of roadsides and other disturbed sites, and riparian habitats.
