Erect, annual herb, c. 25 cm tall. Cauline leaves 5-7 x 4.5-6.5 mm, broadly ovate, 4-5 lobed, with truncate base; terminal lobe acuminate, lateral lobes aristulate, longer than broad, upper antrorse, lower patent (5 x 4-4.5 mm and 4 lobed in aestival and 6-7 x 5-6.5 mm and 5 lobed in the autumnal form). Racemes lax. Floral leaves similar to cauline leaves but lobes as long as broad, 5-10 x 4.5-9.5 mm (5-7 x 4.5-6 mm in aestival and 7.5-10 x 6.5-9.5 mm in autumnal form). Flowers c. 10 mm long. Pedicels c. 1 mm long. Calyx 4-6 mm long; lobes 2-3 x 0.5-1 mm, equal; tube 2-3 mm long. Corolla white, tinged purple, throat yellow, dorsally c. 8.5 mm long; tube c. 3.5 mm long, externally pubescent especially on the upper part of the tube and the upper lip. Upper lip c. 5 mm long. Lower lip c. 6 mm long; lobes oblong-obovate, obcordate, erose-deeply notched, middle lobe largest c. 3.5 x 2.5 mm, left lobe 3 x 2 mm, right lobe 2.5 x 2 mm. Two anthers with unequal and two with subequal awns, densely hairy; hairs short as long as the longer awn. Capsule c. 6 x 2 mm, elliptic, retuse, shorter-subequalling the calyces, ciliate at the upper part; cilia stiff. Seeds 9 per capsule.