Description from Flora of China
Shrubs evergreen. Leaves linear, margin entire, revolute. Floral and to stem leaves similar; bracts petiolate. Flowers subsessile, few, crowded in apical racemes on short branches. Calyx ovoid-campanulate, glabrous on throat inside, 11-veined, 2-lipped, upper lip entire or 3-denticulate, lower lip 2-toothed. Corolla blue-purple, bluish, or whitish, 2-lipped; tube exserted, glabrous inside, dilated at throat; upper lip erect, emarginate or 2-lobed; lower lip large, spreading, 3-lobed; middle lobe largest, concave, declined, margin dentate; lateral lobes oblong. Stamens 2, reaching upper corolla lip; filaments coherent with connectives, with a tooth reflexed below middle; anther cells 2, parallel, only 1 fertile, linear, inserted on top of connective; staminodes absent. Style much longer than stamens, apex unequally 2-cleft, lobes subulate, posterior lobe shorter. Disc ringlike, equally 4-lobed. Nutlets ovoid-globose, smooth, each with an elaiosome.
About three (to five) species: Africa, SW Asia, Europe; one species cultivated in China.
Many recognize this as a monotypic genus.