Description from Flora of China
Herbs annual, biennial, or perennial, strigose. Leaf blade lanceolate. Cymes terminating stems and branches, or in panicles. Flowers frequently pedicellate. Calyx 5-parted; lobes lanceolate-linear, less often broadly lanceolate, slightly enlarged, connivent in fruit, 2 adaxial lobes usually smaller. Corolla blue, purple, or pink, campanulate or tubular, distinctly zygomorphic, usually pubescent outside; tube usually short, with a pubescent or glabrous protective ring inside base, throat unappendaged; limb oblique, lobes unequal in size. Stamens unequal; filaments thin, long, attached at different levels at or below middle of corolla tube, appearing spirally arranged, often exserted; anthers oblong, small. Ovary 4-divided. Style filiform, exserted, appressed pubescent, apex 2-cleft, each branch with a small capitate stigma. Gynobase flat. Nutlets usually light brown, straight, ovoid or narrowly ovoid, tuberculate or smooth; attachment scar at base.
Over 40 species: Africa, W Asia, Europe, introduced to North America; one species in China.