An upright or sprawling herbaceous plant usually growing 10-50 cm tall. Its alternately arranged leaves (2-8 cm long) have winged stalks and bluntly or sharply toothed margins. Its mauve, purple or blue flower-heads are surrounded by a row of 3-8 large leaf-like bracts. These flower-heads have 30-60 small flowers surrounded by several rows of smaller bracts. Its pale brown 'seeds' (1-2.5 mm long) are topped with a row of narrow bristle-like scales (1-3 mm long).