Caulescent herb to 30 cm tall. Lower stem creeping and rooting at the nodes, sometimes swollen, somewhat succulent, flowering stems decumbent, with scattered spreading hairs and subsessile glands. Leaves opposite, somewhat unequal to subequal; blade (ovate-)elliptic, 3–10 cm long, 1.5–5 cm wide, base asymmetrically obtuse to subcordate, margin entire, apex bluntly acute to subacuminate, surfaces sparsely pubescent mainly on the nerves beneath, ciliate; lateral nerves 6(–8) pairs, sometimes purple beneath; petiole 1–4 cm long, sparsely pubescent or glabrescent. Inflorescences axillary to the upper leaves, solitary, 2–10-flowered; peduncles 3–7 cm long, largely glabrous towards the base, becoming sparsely glandular- and eglandular-pubescent and with subsessile glands towards the apex; pedicels 3–6 mm long, with dense subsessile glands and less dense long glandular-hairs; bracts linear, 1–2 mm long, early caducous. Calyx lobes linear-lanceolate, bluntly tipped, 3.5–5.5 mm long, sparsely pubescent with mainly eglandular hairs, with scattered subsessile glands outside and within. Corolla 25–32 mm long; tube mauve, curved-cylindric, 14–17 mm long, laterally constricted, inflated on the roof above the base where 3 mm deep, narrowing to 1.5–2 mm, sparsely glandular-pubescent towards the mouth; limb bilabiate, oblique, lips blue darkening to purple towards centre, throat white; upper lip of two erect, rounded lobes, 5–6.5 mm long, 4–5 mm wide; lower lip protruding, 12–15.5 mm long, lateral lobes rounded or somewhat obtuse, 6–9 mm long, 8.5–10 mm wide, median lobe rounded, 7–10.5 mm long, 9.5–12 mm wide, palate curved upwards, mouth narrow vertically. Stamens arising from the upper third of the corolla tube; filaments 2–3 mm long, glabrous; anther thecae divergent, 0.8 mm wide; staminodes minute. Ovary cylindric, 4–7 mm long, glabrous except for scattered fine hairs and subsessile glands; style white, 4–6 mm long, glabrous; stigma white, capitate, 0.6–0.8 mm wide, papillose. Capsule 35–55 mm long, 1.5–2 mm diameter, glabrous. Seeds 0.6–0.8 mm long, minutely verruculose, slightly longitudinally ridged.
