Description from Flora of China
Herbs annual. Stems branched or simple, slender, hispid. Leaves alternate, 1-veined. Cymes scorpioid; bracts ± opposite flowers. Flowers pedicellate. Calyx 5-parted to base; lobes linear to lanceolate, somewhat enlarged in fruit, apex usually incurved, rarely straight. Corolla funnelform, light blue; tube straight or slightly curved; throat appendaged; limb 5-parted. Stamens inserted at lower part of corolla tube, included; filaments short; anthers oblong, apex with somewhat prominent connectives. Ovary divided; ovules 2. Style entire; stigma capitate. Gynobase subulate. Nutlets 2, each containing 1 seed, tuberculate, with glochids or glabrous; attachment scar near base.
About 15 species: C and SW Asia, Australia, Europe; five species in China.