Strobilanthes cusia
Strobilanthes cusia is a shrub or subshrub growing about 1 metre tall The plant was often cultivated outside its native range for making dyes, and is possibly still cultivated in China, the Indian subcontinent, Myanmar and Malaysia
Herbs 0.5-1.5 m tall, erect, branched, drying blackish, isophyllous to weakly anisophyllous. Stems glabrous or minutely brown puberulent. Petiole 0.5-7 cm; leaf blade elliptic to ovate, 4-20 × 2-9 cm, both surfaces glabrous or abaxially minutely puberulent along veins, abaxially paler green, adaxially dark green, secondary veins 7-9 on each side of midvein, base attenuate, margin serrate, apex acute. Inflorescences terminal or axillary, bracteate spikes, 1-6 cm, often aggregated to form a leafy branched panicle; peduncle 1-12 cm; bracts leaflike, petiolate, oblanceolate, obovate, or spatulate, 1.2-2.5 cm, basally usually sterile; bracteoles linear-oblanceolate, 2-3 mm, deciduous before bracts. Calyx 0.8-1.5 mm in flower, accrescent to ca. 2.5 cm in fruit, minutely puberulent, 5-lobed almost to base; 4 lobes linear-lanceolate, apex acute to obtuse; 1 lobe oblanceolate and much longer. Corolla blue, 3.5-5 cm, straight to slightly bent, outside glabrous; tube basally cylindric and ca. 3 mm wide for 1-1.5 cm then slightly curved and gradually widened to ca. 1.5 cm at mouth; lobes oblong, ca. 9 × 9 mm, subequal. Stamens 4, included; filaments glabrous, shorter pair ca. 3 mm, longer pair ca. 7 mm; anther thecae oblong, ca. 3 mm; pollen type 4. Ovary oblong, apex puberulent with few gland-tipped trichomes; style ca. 3.2 cm, glabrous. Capsule 1.5-2.2 cm, glabrous, 4-seeded. Seeds ovate in outline, ca. 3.5 mm, covered with appressed trichomes; areola small. Fl. Jul-Feb, fr. Dec-Feb. 2n = 16, 32.
Chian: Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Sichuan, Taiwan, SE Xizang, Yunnan, Zhejiang;
Bangladesh, Bhutan, India, Laos, Myanmar, Thailand, Vietnam
Usually in moist wooded places, sometimes cultivated; 100-2000 m.
Strobilanthes cusia is reported to flower irregularly. The species is perhaps pliestesial.
In at least part of its stated range Strobilanthes cusia may be cultivated rather than native.
This is a medicinal and dye plant and is the source of "Assam indigo."
Decoction from root is used for fever.