A short-lived herbaceous plant usually growing 60 to 120 cm tall, but sometimes reaching up to 2 m in height. Its forms a basal rosette of leaves at first, followed by upright and much-branched stems. Its stems are spiny, winged, and usually have a covering of woolly white hairs. Its leaves (up to 45 cm long and 10 cm wide) are usually deeply lobed, with their margins armed with spines. Its purpish flower-heads (3-5 cm across) are enclosed in numerous spiny bracts. Its greyish or light brown 'seeds' (2.5-4 mm long) are initially topped with a ring of whitish feathery bristles (8-25 mm long).