Description from Flora of China
Herbs perennial, pilose or hispid. Leaves alternate, entire. Cymes densely flowered, or many cymes becoming paniculate, bracteate or ebracteate. Calyx 5-parted to base; lobes linear, lanceolate to oblong, scarcely enlarged. Corolla tubular, rarely campanulate, included or slightly surpassing calyx; appendages oblong, inserted at below middle of corolla tube; limb blue or purplish red; lobes 5, vertical or somewhat spreading. Stamens inserted above corolla appendages, exserted; anthers oblong to broadly elliptic, apex obtuse. Style usually exserted; stigma minute. Gynobase fastigiate. Nutlets dorsiventrally compressed, ovate to suborbicular, 5-10 mm, abaxially discoid, flat or slightly concave, with dense glochids on abaxial margin and adaxially; attachment scar above middle adaxially, occupying ca. 1/2 of surface, firmly coherent to gynobase.
About ten species: C and W Asia, SE Europe; two species in China.