Jacobaea vulgaris is a biennial to short lived perennial herb native to Eurasia. Plants can reach 1-4 ft. (0.3-1.2 m) tall.
Foliage
The leaves of the basal rosette have petioles, cauline (stem) leaves are sessile and both are deeply lobed and alternate. The leaf lobes are oblong and web-shaped. The margins of the leaves are dentate. The leaves can measure between 1.5-8 in. (4-20 cm) long and 0.75-2.25 in. (2-6 cm) wide. The leaf is medium green above, lighter underneath and occasionally tomentose.
Flowers
Flowering occurs in summer to early fall, when numerous yellow, daisy-like flowers develop in a flat topped inflorescence at the apex of the stems. Flower heads are 0.8 in. (2 cm) in diameter.
Fruit
Fruit are small and have a persistent ring of white hairs (pappus) attached. 60,000-70,000 seeds produced per plant. Seeds can remain viable for up to 15 years.
Ecological Threat
J. vulgaris invades rangelands in the West where it is toxic to livestock. In the East it invades pastures, open forests, swamps, riverbeds, coastal grasslands and disturbed areas. It was first reported in the United States in the early 1900’s. It is native to most of Europe, North Africa and western Asia and may have been introduced into the United States as a medicinal plant.