Description from Flora of China
Herbs perennial, erect, pubescent. Stems usually cespitose, branched or simple. Leaf blade entire. Cymes terminal, becoming corymbose or paniculate, ebracteate. Flowers pedicellate. Calyx 5-parted; lobes narrow, reflexed in fruit. Corolla tubular-campanulate; throat appendages lunate to ligulate, rarely wanting, sometimes a second whorl of appendages near middle or base of tube; lobes of limb 5, overlapping, vertical or divaricate, usually lanceolate, ca. as long as tube, rarely shorter. Stamens inserted below throat appendages of corolla tube; filaments filiform; anthers oblong to linear, partly or completely exserted, base hastate, apex obtuse, rarely acute. Ovary 4-parted. Style filiform, exserted, rarely included; stigma capitate. Gynobase fastigiate or subulate. Nutlets 4, orbicular or ovoid; abaxially concave, glabrous, margin with wide flat spreading wings, keeled along center line.
About 25 species: C Asia, Europe; one species in China.