Ambrosia artemisiifolia
L. Common RagweedErect annual herb to 2 m high, shallow-rooted, non-stoloniferous; stems usually simple, with long spreading hairs. Leaves alternate, sometimes opposite above, lanceolate to ovate in outline, mostly 1–16 cm long and 1–5 cm wide, bipinnate to bipinnatisect with lanceolate or oblong segments mostly 2–4 mm wide, surfaces finely hairy to glabrescent; petiole to 2 cm long. Inflorescences often several together, 3–10 cm long. Male capitula numerous, 2–3 mm diam., yellow-green or white; peduncles c. 1 mm long; florets many, slightly exceeding involucral bracts. Female capitula in small clusters in upper axils; fruiting capitula obovoid, c. 3 mm long, with 4–14 spines with erect or recurved apices, apex with a central beak. Flowers summer and autumn.
Also naturalised WA, Qld, NSW. Native to North America. In Victoria known only by an old collection from Cape Paterson but probably more widespread than this.
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.
Spinning
