Jacobaea aquatica

Jacobaea aquatica (formerly Senecio aquaticus), the marsh ragwort or water ragwort, is a biennial to short-lived perennial herb in the family Asteraceae. Young plants form a flat basal rosette of stalked, lyrate-pinnatifid leaves with a large terminal lobe and smaller lateral lobes; from this rosette the plant produces erect, leafy flowering shoots typically 30–80 cm tall in the second year. The upper stem leaves are stalkless and more deeply pinnatifid. From June to August it bears loose, flat-topped corymbs of many bright yellow flower heads, each up to about 2.5–3 cm across with prominent ray florets and a yellow disc, followed by small ribbed cypselae with a pappus of fine white hairs. It is endemic to Europe, occurring throughout the continent except in Finland and parts of eastern Europe, and grows in damp, grazed grassland, wet meadows, marsh edges and disturbed wetlands. Like other ragworts it contains pyrrolizidine alkaloids and is regarded as toxic.