Taprooted annual; stems erect, sometimes much-branched, to c. 40 cm tall. Vegetative parts glabrous. Lvs 1.5-4 cm long, narrow-linear, green; apex ± obtuse. Infl. many-flowered, glabrous or glandular-puberulent; fls in rather lax and elongated racemes. Bracts 3-5-(10) mm long, linear to lanceolate, 1/4-3/4 length of pedicels. Calyx 4-6 mm long, lobed almost to base; lobes lanceolate or linear-lanceolate, usually glandular-hairy, occasionally glabrous, acute or acuminate. Corolla 25-30 mm long (including slender, straight, acute spur c. 15 mm long), usually crimson or purplish, sometimes pale yellow to orange, pink, or bicoloured, except for yellow or orange, puberulent pouch; upper lip 10-15 mm long. Capsule 3-5 mm diam., globose. Seeds 1.7-1.9 mm long, curved, wingless, black, strongly ribbed.