Perennials, 30-120 cm (rhizomes branched, sometimes producing stolons). Herbage floccose-tomentose, unevenly glabrescent (persistently hairy on abaxial leaf faces). Stems usually single, sometimes loosely clustered. Leaves ± evenly distributed (basal and proximal sometimes withering before flowering); petiolate (proximal) or sessile; blades ovoid or oblong to spatulate (usually pinnatifid to pinnatisect, lobes ± lanceolate to linear), (3-)5-12 × (1.5-)2-4 cm, bases tapered to ± truncate, ultimate margins (often revolute) dentate or entire. Heads 20-60 in corymbiform arrays. Calyculi of 4-6(-10) bractlets (lengths to ¹ / 2 phyllaries). Phyllaries ± 13, 5-7 mm, tips green or greenish. Ray florets ± 13; corolla laminae 12-15 mm. Cypselae hairy.

Flowering summer. Waste grounds; 0-200+ m; introduced; Pa.; Old World.

Senecio erucifolius has been introduced occasionally around seaports and has persisted. At present, it appears to be uncommon and highly localized; it should be expected almost any place that its close relative, Senecio jacobaea, occurs.

Senecio erucifolius was treated in Jacobaea by E. Wiebe (2000); see discussion under 53. S. jacobaea.