Trailing or climbing herb; stem twining, terete, glabrous; leaves simple, alternate, exstipulate, ovate or oblong, base cordate or auriculate; flowers axillary. solitary or fascicled; penduncles long, slender; pedicels often very short; bracts small, bracteoles-2; calyx segments-5, elliptic-ovate, truncate, unequal, outer wider, glabrous; corolla blue or purple rarely white, 5-plaited, broadly funnel shaped, tube short, glabrous; stamens-5, epipetalous, filaments unequal, anthers short, oblong; ovary 2-celled, 4-ovuled, style filiform, stigmas-2, distinct, oblong or linear; capsule ovoid or globose, glabrous, 4-valved, bursting irregularly; seeds 4, small, brown, glabrous.