Erect, annual herb, 10-25 cm tall. Cauline leaves 4-7 x 2-4 mm, elliptic-ovate; (3) 4-5 lobed, with truncate base; lobes acuminate, as long as broad, all antrorse (4-5 x 2-2.5 mm, elliptic, 3-4 lobed in aestival and 5.5-7 x 3-4 mm, ovate, 5-lobed in autumnal form). Racemes lax. Floral leaves 3-7 x 2.5-6 mm, ovate-slightly broadly ovate, 4-6 lobed, with truncate base; lobes acuminate, as long as broad, rarely longer than broad, upper antrorse lower patent (3-4 x 2.5-3.5 mm, ovate, 4-lobed, in aestival and 4.5-7 x 4.4-6 mm, broadly ovate, 5-6 lobed in autumnal form). Flowers 7-10 mm long; pedicellate-subsessile. Calyx 3-5 mm long; lobes 1-2.5 x 0.5-2 mm, equal; tube 1.5-3 mm long. Corolla white, tinged purple, dorsally 6.5-9.5 mm long; tube 3-5 mm long, externally sparsely pubescent on the upper lip and the tube. Upper lip 2.5-4 mm long. Lower lip 3-4 mm long; lobes oblong-obovate, obcordate, erose-deeply notched, middle lobe largest 2-2.5 x 1-2 mm, left and right lobes equal or unequal, right and left lobes 1.5-2 x 1-2 mm. Two anthers with unequal and two with subequal awns, densely hairy; hairs, short, equalling the shorter awns. Capsule 3.5-6 x 1-2.5 mm, (3.5-4 x 1-2 mm in aestival and 4.5-6 x 2.5 mm in autumnal form), oblong, retuse, ciliate all over; cilia soft. Seeds 7 per capsule, oblong, obtuse.