Description from Flora of China
Herbs or subshrubs, rarely shrubs, not aromatic. Leaves entire to pinnatifid. Inflorescences terminal or axillary racemes or spikes; floral leaves usually bractlike apically. Flowers axillary, opposite or sometimes alternate apically. Calyx short tubular, dorsiventrally flattened, 2-lipped; lips entire, closed and ultimately divided to base along sutures in fruit; upper lip deciduous, with a transverse, rounded, concave, scalelike scutellum (shield) or without and abaxially conspicuously saccate; lower lip persistent. Corolla 2-lipped; tube exserted, arcuate or suberect, gradually widening to throat, base bent and saccate or spurred, usually puberulent annulate outside; upper lip erect, galeate; lower lip 3-lobed, middle lobe broad, flattened, entire, lateral lobes ± joined to upper lip and sometimes spreading. Stamens 4, didynamous, anterior 2 longest, underlying upper lip; anthers close together in pairs, bearded on cell aperture; posterior pair conspicuously 2-celled, ± apically acute, anterior pair 1-celled by abortion. Style subulate, apically unequally 2-cleft. Nutlets oblate, globose, to ovoid.
About 350 species: worldwide, but only a few in tropical Africa; 98 species in China.
A very isolated genus with unsatisfactory traditional divisions. Paton (Kew Bull. 45: 399-450. 1990) has proposed a revised classification of Scutellaria but did not deal with a large
number of the Chinese taxa, and it is not possible to utilize his divisions in detail.