Erect, annual or perennial herbs; stem glabrous below, branched from the base, more or less glandular-hairy above; lower leaves opposite, upper alternate, entire or lobed, narrowly oblong, acute or acuminate at apex, glabrous or pubescent, sessile or sub-sessile; flowers axillary, solitary or in lax racemes, pale pink, streaked with purple yellow or in many colours; sepals very narrow, spreading; corolla white-yellow or pale pink, compressed base, saccate, 2-lipped, upperlip 2-lobed, erect, lowerlip 3-lobed, spreading, palate broad, bearded closing the throat; stamens-4, didynamous, anther cells parallel, distinct, filaments filiform or dilated at apex; ovary 2-celled, style filiform, stigma bilobed; capsules globose or ovoid, cells-2, many seeded, anterior opening by a pore, posterior by 2-toothed pores or opening by one pore; seeds minute, oblong, rugose or pitted, compressed, concave, back keeled, margins thickened.