Senecio aquaticus Hill
marsh ragwort
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.
N.: established in the vicinity of Levin, also collected once from Mercer (S. Auckland); S.: locally established in Nelson Province (Waimea, Buller R., Owen R. and Westport), also collected once from Lake Monowai (Southland).
Europe E. to Jugoslavia 1899
Waste places, riverbanks.
FL Jan-Jun.
Marsh ragwort is distinguished from the similar, widespread S. jacobaea by the less dissected lvs, diffuse infls, and usually by the glabrous disc achenes. N.Z. material is referable to the type subsp.
