Scientific Name:
Jacobaea aquatica (Hill) P.Gaertn., B.Mey. & Scherb. (1802)
  • Senecio aquaticus Hill, Veg. Syst. 120 (1761)

Erect, biennial herb, 20–70 cm tall. Stems densely lanate when young but soon glabrous, branched or not from base. Basal lvs lanate when young, soon almost glabrous, petiolate; petiole < lamina, amplexicaul; lamina pinnatifid toward base or not lobed, ovate-oblong to elliptic, obtuse to subacute at apex, regularly or irregularly crenate or serrate, c. 25–120 × 15–50 mm; venation pinnate. Cauline lvs lyrate-pinnatifid to 1-pinnate with irregularly once-toothed, oblong segments; uppermost lvs apetiolate, pinnatisect with narrow segments. Capitula in open panicles. Supplementary bracts 3–10–(16), lanceolate, 1.5–6 mm long. Involucral bracts 13–22, ovate-oblong, usually glabrous, sometimes sparsely hairy, 3.5–5.5 mm long. Ray florets 13–20; ligules yellow, 5–11 mm long. Disc yellow. Achenes terete, usually glabrous, rarely innermost sparsely hairy, c. 2 mm long; pappus 3–3.5 mm long.

[From: Webb et al. (1985) Flora of New Zealand. Volume 4 as Senecio aquaticus Hill]

Hill, J. 1761: Vegetable System. Vol. 2.
Pelser, P.B.; Veldkamp, J.-F.; Meijden van der, P. 2006: New combinations in Jacobaea Mill. (Asteraceae - Senecioneae). Compositae Newsletter 44: 1–11.