Annual, 10-25 cm, stem rigidly erect, leafy throughout, with patent lanate hairs above and hooked hairs below. Leaves 4 x 1 cm, narrowly to broadly lanceolate to ovate, with hooked hairs beneath. Flowers distant below, crowded above. Pedicels c. 1 mm in fruit, almost always deflexed at maturity. Calyx accrescent, to 4.6 mm in fruit, divided to c. 1/3 , open, with strongly deflexed, hooked hairs and short, delicate straight hairs at base, deciduous. Limb of corolla to 1.5mm diam., flat or rather smaller and saucer-shaped, pale to bright blue. Nutlets 2 x 1 mm, ellipsoid or narrowly obovate, with a small lateral attachment scar and distinct rim, ventrally furrowed from apex to base.
1. Calyx-tube ± evenly covered with hooked hairs; nutlets furrowed ± in middle subsp. refracta
1. Calyx tube without hooked hairs in lower ½ ; nutlets with a narrow lateral furrow subsp. paucipilosa