Unarmed annual or perennial herbs, glandular-hairy and ± viscid. Lvs mostly alternate, simple, entire, petiolate. Fls solitary and axillary or in terminal racemes with the lvs gradually passing into bracts. Calyx deeply 5-toothed; teeth linear, oblong, or spathulate. Corolla funnelform or salverform, rolled inwards in bud, of most colours; tube with narrow-cylindric base; lobes 5, shallow, equal or slightly irregular with limb slightly oblique. Stamens included, 4 in 2 pairs, with 1 small or rudimentary staminode inserted around or below middle of corolla tube. Capsule small; valves 2. Seeds numerous, tiny, rugose.