Erect, glandular-hairy, odorous annual to c. 60 cm tall. Leaves sessile, ovate to oblong-lanceolate, pinnatisect to bipinnatisect, 15–35 mm long, 10–25 mm wide, lobes narrow, rigid and spine-tipped. Inflorescences dense terminal heads 2–3 cm across, surrounded by spine-tipped leafy bracts. Sepals 5, narrow-lanceolate, 8–12 mm long, teeth about as long as tube, spinose; corolla 5-lobed, 9–12 mm long, broadly funnel-shaped, pale lilac to blue, lobes short, spreading; stamens inserted at c. middle of corolla-tube, anthers included; stigma 3-lobed. Capsule ovoid, 3–4 mm long, 3-celled, remaining enclosed by persistent calyx; seeds numerous. Flowers summer.