Ragwort

Senecio jacobaea

Family: Asteraceae.

Form: Herb

Origin: Native of Europe.

Flowers/Seedhead: Small flowers (florets) in heads mostly about 2.5 cm wide. Flowers mostly spring to autumn.

Description: Biennial or short-lived perennial herb to 0.8 (rarely to 1.8) m high. Stems often branched towards apex. Basal leaves mostly 5–20 cm long and 4–6 cm wide, in a rosette, withering in flowering plants; stem leaves with upper surface dark green, underneath lighter in colour. Seeds of outer (ray) florets are hairless, those from the inner (disc) florets have fine bristles.

Distinguishing features: Distinguished by stem leaves deeply divided and irregularly lobed; flowerheads numerous, often in flat-topped clusters at end of stems; bracts around flowerheads 11–14 in one row, 3–6 mm long; yellow disc florets surrounded by 11–15 bright yellow petal-like ray florets 4–12 mm long; seeds 1.5–3 mm long, topped with persistent bristles 4–6 mm long.

Dispersal: Mainly by seed spread by water, on animals, in stock feed or in mud attached to vehicles. Seed may be spread by wind dispersal but mainly over short distances.

Confused With: Other Senecio species, see taxonomic texts for detailed distinguishing features.