Erect, annual herb, 3-12 cm tall. Cauline leaves 4.5-9 x 3-6 mm, ovate or elliptic, 4-lobed; with truncate base; lobes acute-obtuse slightly aristulate, as long as broad, upper antrorse, lower patent (4.5-6 x 3-4 mm, elliptic, lobes obtuse in aestival and 6.5-9 x 4.5-6 mm, ovate, lobes acute or slightly aristulate in autumnal form). Flowering begins at node (-1) 2-3 (from node 2 in aestival and from node 3 in autumnal form). Racemes lax. Floral leaves similar to cauline leaves but ovate or broadly ovate and lobes acute-slightly acuminate, 4-9.5 x 3-9.5 mm (4-6 x 3-4 mm, ovate, lobes acute in aestival and 6.5-9.5 x 4.5-9.5 mm, broadly ovate, lobes acuminate in autumnal form). Flowers 5-9 mm long, sessile. Calyx 3.5-5 mm long; lobes 2-3.5 x 0.5-1 mm, equal or unequal; tube 2-3 mm long. Corolla yellow with violet streaks, throat yellow, dorsally 5-9 mm long; tube 2-5.5 mm long, externally pubescent especially on the upper lip. Upper lip 2-4 mm long, lower lip 3-5 mm long; lobes oblong or obovate, obcordate, erose-slightly notched, middle lobe largest 1.5-3 x 1-3.5 mm, left and right lobes equal or unequal, left lobe 2-3 x 1.5-4.5 mm, right lobes 2-2.5 x 1-2 mm. Two anthers with equal and two with unequal awns; hairs short equalling the shorter awns. Capsule 3-6 x 1.5-2.5 mm (3-4 x 1.5-2 mm in aestival and 4.5-6 x 2-2.5 mm in autumnal form), oblong, retuse, shorter than the calyces, ciliate at the upper part; cilia soft. Seeds 4-7 per capsule (c. 4 seeds in aestival and 5-7 seeds in autumnal form), oblong, obtuse.