Annual or short-lived perennial, 30-50 cm. Stems weakly erect, leafy, quadrangular, little branched, with short eglandular hairs. Leaves broadly ovate, 3-7 x 2. 5-5 cm, thin-textured, with a thin indumentum of short simple eglandular hairs on both surfaces, gland-dotted below, crenate, cuneaterounded; petiole up to 3 cm on lowermost leaves, sesile above. Cymes on slender peduncles forming short panicles. Pedicels slender, erect-spreading, 4-6 mm. Calyx in flower 1-1.5 mm, ± densely gland-dotted and with few or no eglandular hairs; teeth subequal, obtuse; fruiting calyx 3-3. 5 mm, obliquely campanulate, curved. Corolla white or with purplish markings, 6-8 mm; tube c. 5 mm straight, clearly exserted from calyx, not gibbous; lower lip somewhat longer than upper. Nutlets c. 0.8 x 0.5 mm, smooth, pale brown, mucilaginous on wetting.