Erect, glabrous to sparsely papillose annual, 10–60 cm high; stems solitary or few from near base. Leaves oblanceolate to obovate-spathulate, c. 6–35 mm long, 2–12 mm wide, toothed (but reducing and c. entire up stem); petiole indistinct. Flowers bisexual, in terminal and sometimes axillary 4–13-flowered racemes; pedicels 3–35(–45) mm long, glabrous or rarely papillose. Calyx-lobes 1.8–5 mm long, entire; corolla 2-lipped, (10–)13–28 mm long, usually dark blue, rarely white; upper 2 lobes short, strongly recurved, lower 3 lobes spreading, oblong to oblanceolate, the central lobe longest, (5–)8–15 mm long, 1.2–5 mm wide, lateral lobes falcate, tube 5–9(–15) mm long, split almost to base, glabrous to minutely pubescent internally towards base; filaments 3.5–8 mm long, anther tube c. 1.7–2.5 mm long. Capsule broadly and obliquely obovoid, c. 5–8 mm long; seeds c. ellipsoid, 0.3–0.45 mm long, brown, very faintly ridged to almost smooth. Flowers most of year.
