Erect, perennial, shrub reaching about 1 m in height; branches many from the base, more or less glabrous; leaves variable, ovate, cuneate or obtuse at base, entire or coarsely toothed in the upper half, acute or rather obtuse glabrous; flowers large, showy, deep blue or white, solitary, axillary; bracteoles at the base of pedicels, deciduous, ovate- lanceolate; calyx hidden by foliaceous bracts, teeth 12-15, subulate, glandular-pubescent; corolla blue-violet, tube long, curved, lobes rounded subequal; stamens-4, attached at the throat of tube, filaments glabrous; ovary 2-locular; ovules 2 in each locule, style long, stigma entire, 2-fid; capsule globose or conical, 1.5-2 cm long, 4 seeded; seeds ovoid, globose or hemispherical, glabrous.