Small, much branches, slender herb, up to 10-12 cm high; stem slender, tetrangular; leaves subsessile narrowly elliptic or lanceolate, acute at apex, tapering at base, usually 3 nerved; flowers tetramerous, few clustered in terminal, multifid cymes; pedicels slender; calyx deeply 4-5 lobbed, segments keeled, winged or flat; corolla 4-5 lobed, rotate, tube very short, ovate-oblong, purple, blue or white; stamens-4-5, attached on the throat of corolla, filaments short, anthers, large, oblong, dehiscing with pore at apex, halfway down to the base; ovary-2 celled, style long, stigma subcapitate, small, placenta large; capsule globose, 2-valved; seeds very many, minute, subcuboid.