Erect biennial, (10–)30–150 cm high, hispid especially on primary stems; stems striate. Leaves 2–3-pinnate, lamina to 28 cm long; ultimate segments ovate to lanceolate or linear, c. 1 cm long; petiole of lower leaves shorter than lamina, base sheathing. Umbels c. flat-topped in flower, 4–10 cm diam.; rays 30–60, becoming rigid and incurved in fruit; umbellules to 25-flowered, outer flowers yellow or white or pink, c. 2.5 mm diam., inner flowers sterile and black or purple; involucral bracts 7–13, pinnatifid, often shorter than rays; involucral bracteoles linear, entire or trifid. Petals c. 1 mm long. Fruit ovoid, 2–4 mm long; primary ribs with a row of short hairs; secondary ribs with straight spines, only apical spines barbellate. Flowers mainly spring–autumn (smaller flowering plants sometimes seen in winter).