Erect, annual herb, 10-20 cm tall plant sometimes tinged purple. Cauline leaves 5-10.5 x 3-7 mm, ovate, 4-5 lobed, with cuneate base; lobes acuminate-slightly aristulate, as long as broad or broader than long, all antrorse (5-7 x 3-4 mm in aestival and 7.5-10.5 x 4.5-7 mm in autumnal form). Racemes lax, sometimes slightly dense at the upper portion. Floral leaves 4-16 x 2-11 mm, ovate to broadly ovate, trullate, oblong or elliptic, 4-5 lobed; terminal lobe acuminate, lateral lobes acuminate-aristulate, as long as broad or broader than long, all antrorse (4-7 x 2-6 mm, ovate, 4-lobed, lobes acuminate, broader than long in aestival and 7.5-16 x 6.5-11 mm, broadly ovate, 5-lobed, lobes aristulate, longer than broad in autumnal form). Flowers 8-11 mm long; pedicels 0.5-1 mm long. Calyx 4-6 mm long; lobes 1-4 x 0.5-1 mm, usually equal; tube 1-4 mm long. Corolla purplish, dorsally 5-10.5 mm long; tube 2-5 mm long, externally finely pubescent especially on the upper lip and the tube. Upper lip 2-4.5 mm long. Lower lip 3-5 mm long; lobes oblong-obovate, obcordate, slightly erose-deeply notched, middle lobe largest 2-3.5 x 1-2.5 mm, left and right lobes unequal, left lobe 1.5-3 x 1-2 mm, right lobe 1-3 x 1-2 mm. Two anthers with equal and two with unequal awns, finely hairy; hairs short, equalling the longer awn. Capsule 4.5-7 x 1.5-3.5 mm (c. 4.5 x 1.5 mm in aestival and 5-7 x 2-3.5 mm in autumnal form), oblong, retuse, shorter than calyces, sparsely ciliate at the upper part; cilia short and soft. Seeds 6-11 per capsule (6-7 seeds in aestival and 8-11 seeds in autumnal form), oblong, obtuse.