Description from Flora of China
Plectranthus L'Heritier sect. Isodon Bentham, Labiat. Gen Spec. 40. 1832; Rabdosia (Blume) Hasskarl.
Shrubs, subshrubs, or perennial herbs. Rhizomes woody, massive. Leaves usually petiolate, dentate. Cymes (1-)3- to many flowered, in ± lax thyrses or narrow or open panicles, rarely in dense spikes. Flowers pedicellate. Calyx campanulate to tubular-campanulate, straight or declinate, often dilated; limb equally or subequally 5-toothed or 2-lipped, upper lip 3-toothed, lower lip 2-toothed. Corolla tube exserted, declinate or abruptly deflexed, sometimes straight, ± saccate to spurred abaxially near base, 2-lipped; upper lip 4-cleft, recurved or reflexed; lower lip entire, concave, navicular. Stamens 4, declinate; filaments free, edentate; anther cells 2, apex usually confluent. Style apex short 2-cleft. Nutlets subcircular or occasionally oblong to ovoid, glabrous or hairy, smooth, granular or dotted.
About 100 species: Asia, only a few species in Africa; 77 species in China.