Perennial with shortly decumbent vegetative shoots, rooting at nodes and often forming mats; flowering stems ± erect and ascending to c. 25 cm, puberulent. Petioles very short. Lamina 5-17 × 4-15 mm, broadly ovate, broadly elliptic or orbicular, glabrous, slightly crenulate; base and apex ± rounded. Infl. a narrow, elongated, terminal raceme; peduncle and pedicels puberulent; pedicels 2-6 mm long; lower bracts leaflike; upper bracts becoming smaller and narrower, oblong, entire, > pedicels. Calyx 2-3 mm long; lobes elliptic or ovate-elliptic, glabrous or almost so, obtuse. Corolla c. 8 mm diam., white or very pale blue, with fine dark blue veins. Capsule c. 4 mm wide, obcordate, sometimes ciliolate; nerves inconspicuous. Seeds oblong to ellipsoid, strongly flattened.