Plants annual or
perennial herbs. Stems erect or loosely ascending, unbranched or few-branched.
Leaves sessile or petiolate, the margins entire or sharply toothed.
Inflorescences spikes, racemes, or panicles, the flowers from the axils of
mostly reduced (much shorter and narrower than the leaves) bracts. Flowers
epigynous, not cleistogamous. Calyces actinomorphic, all 5-lobed, often with a
short, reflexed appendage between each of the lobes, persistent at fruiting.
Corollas actinomorphic, funnel-shaped to bell-shaped or saucer-shaped, 5-lobed,
but usually not divided below the middle, commonly blue or white. Stamens 5,
attached to the base of the corolla, the filaments dilated and hairy at the
base, the anthers distinct, elongate. Pistil with 3–5 carpels. Ovary
totally inferior, with 3–5 locules. Style elongate, the stigma
3–5-lobed. Fruits obconical to nearly globose capsules, often
longitudinally ribbed, dehiscent by 3–5 lateral pores or slits. Seeds
ellipsoid, sometimes somewhat flattened, the surface brown, shiny. About 300
species, nearly worldwide, but most diverse in temperate portions of the