Erect, annual herb, 15-18 cm tall. Cauline leaves 5-7 x 2.5-6 mm, elliptic, 4-lobed, with truncate base; lobes acuminate, longer than broad, upper antrorse, lower patent (c. 5 x 2.5 mm, in aestival and 5.5-7 x 3-6 mm in autumnal form). Racemes dense. Floral leaves 6-7 x 6-7 mm, broadly ovate, 4-5 lobed with cuneate base; terminal lobe acuminate, lateral lobes acuminate-slightly aristulate, longer than broad, upper antrorse, lower patent (c. 6 x 6 mm and 4-lobed, in aestival and c. 7 x 7 mm and 5-lobed in autumnal form). Flowers 8-10 mm long; pedicellate-sessile. Calyx 4-6 mm long; lobes 2-3 x 0.5-1 mm, equal or unequal; tube 1-4 mm long. Corolla violet, dorsally 7-9 mm long, tube 5 mm, externally pubescent especially on the upper lip. Upper lip 2-4 mm long. Lower lip 3-4 mm long; lobes oblong, obcordate, erose-slightly notched, middle lobe largest 1.5-3 x 1.5-2.5 mm, left and right lobes equal, 2.5-3 x 1.5-2 mm. Two anthers with unequal and two with equal awns, densely hairy; hairs short, equalling the longer awn. Capsule 4.5-5.5 x 2-2.5 mm (c. 4.5 x 2 mm in aestival and 5-5.5 x 2.5 mm in autumnal form), oblong, retuse, shorter than the calyces, ciliate at the upper part; cilia soft. Seeds 8-10 per capsule (c. 8 seeds in aestival and 9-10 seeds in autumnal form), oblong, obtuse.