Erect, glabrous, strongly aromatic annual, up to 1–2 m tall. Stems usually with many short branches. Lvs 1-pinnate, shortly petiolate; leaflets in 3–8 pairs, linear to lanceolate, 2–8 cm long, with (8)–15–40 teeth on each side, moderately covered in large, sessile, glands, especially on lower surface. Upper cauline lvs smaller than lower, with fewer leaflets and teeth. Capitula 3–7 mm diam., in dense corymbs; peduncles solid. Involucre narrow-cylindric, 8–12 × 2–3 mm, with 3–5 short teeth at apex; glands long, many, evenly distributed above and below. Ray florets 1–3–(4); ligules yellowish green or cream, 1–3 mm long. Disc florets few, green. Achenes 3–4-angled toward base, dark brown, densely clothed in short antrorse hairs, 5.5–7 × 0.7–1 mm; pappus scales free, the longest 2.5–3 mm and with minute marginal antrorse hairs.
[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]