Erect, annual herb. Cauline leaves 6-9 x 5-6 mm, ovate-broadly ovate, 3-6 lobed, with truncate base; lobes acuminate, longer than broad, upper antrorse, lower patent (6-7 x 5 mm, ovate, 3-lobed in aestival and 7.5-9 x 5.5-6 mm, broadly ovate, 4-6 lobed in autumnal form). Spike lax, dense and broad at the upper portion. Floral leaves similar to cauline leaves but lateral lobes acuminate-aristulate, 7-9 x 5.5-6.5 mm (c. 7 x 5.5 mm, lobes acuminate in aestival and 7.5-9 x 6-6.5 mm, lobes aristulate in autumnal form). Flowers 10.5-11.5 mm long, sessile. Calyx 5.5-6.5 mm long, lobes 2-4 x 1 mm, equal or unequal; tube 1.5-4.5 mm long. Corolla with upper lip purplish, lower lip pale, throat yellow, dorsally 8-9 mm long; tube 4-6 mm long, externally pubescent especially on the upper lip. Upper lip 3-4 mm long. Lower lip 6-8 mm long; lobes oblong-obovate, rarely spathulate, erose-deeply notched, middle lobe largest 3-4 x 2-4 mm, left and right lobes unequal, left lobe 2-3.5 x 2-3.5 mm, right lobe 2-3 x 3-4 mm. Two anthers with equal-subequal and two with unequal awns, densely hairy; hairs long twice as long as the longer awn. Capsule 7-8 x 2-3 mm (c. 7 x 2 mm in aestival and c. 7.5-8 x 2.5-3 mm in autumnal form), oblong-obovate, emarginate, longer than the calyx, ciliate at the upper part; cilia soft. Seeds 4-12 per capsule (4-9 seeds in aestival and 10-12 seeds in autumnal form) oblong, obtuse.