Annual, up to 60 (-90) cm tall herb with ascending branches. Leaves simple, alternate, sessile, basal and lower linear-lanceolate, 3 – 10 cm long, 4 – 5 mm wide, median and upper ± smaller, 2 – 3 mm broad, with 1 – 2 (-3) basal subulate denticles on each side, all greyish white woolly beneath, acute. Capitula solitary, terminal on all branches, radiant, 2 – 2. 5 cm across. Involucre oblong-campanulate, 1.2 – 1.5 cm long, 6 – 8 (-10) mm wide. Phyllaries unarmed, green, tomentose to glabrescent, outer ovate, inner oblong, all with erect, brown or purple-tinged, appendages divided into 0.5 – 1 mm long teeth or lacerations. Florets 25–30 per capitulum, violet blue, (sometimes purple or white); marginal florets strongly radiant, sterile, 1.8 – 2 cm long; central florets perfect, ca 1.5 cm long including 4 – 5 mm long limb lobes and distinctly curved; anther tube purple. Cypselas pale-blue, 3 – 4 mm long, finely hairy. Pappus of many unequal, 2 – 3.5 (– 4) mm long bristles.