Hairy undershrubs with ovate or narrowly oblong, entire or toothed leaves. Flowers sessile or subsessible, solitary, usually crowded on lateral branches, white or blue; bracts absent or small and narrow; bracteoles 2, large, ovate, reticulately nerved and ultimately scarious. Calyx unequally 5-lobed to the base, lobes narrowly linear-lanceolate. Corolla straight or curved, tube dilated upwards or infundibuliform, limb subequally 5-lobed, lobes twisted to the left in bud, rounded. Stamens 4, didynamous, all fertile; anthers dithecous, oblong, sagittate and bristle-tipped at the bases, Ovary bilocular, each locule biovulate; style long, linear, stigma unequally 2-lobed. Capsule compressed, ± stipitate, 2- or 4-seeded. Seeds discoid, covered with hygroscopic hair, borne on elastically separating placentae.