Description from Flora of China
Wrightia hainanensis Merrill; W. hainanensis var. variabilis Tsiang; W. tinctoria R. Brown var. laevis (J. D. Hooker) Pichon.
Trees to 40 m tall, glabrous except for flowers. Bark dark gray, branchlets brownish, lenticellate. Petiole 5-7 mm; leaf blade oblong or narrowly elliptic, rarely ovate, 7-18 X 2.5-8 cm, apex acuminate to caudate-acuminate; lateral veins 5-11 pairs. Cymes ca. 6 cm; peduncle ca. 1 cm, puberulent to glabrous. Pedicel 1-1.5 cm. Sepals broadly ovate, ca. 1 mm, pubescent outside, apex rounded or obtuse. Corolla white or yellowish, funnelform, tube 1.5-3 mm; lobes narrowly elliptic, 5.5-13.5 mm, papillate; corona fringed, scales 25-35, linear, puberulent. Anthers as long as corona, puberulent. Ovaries 2, distinct. Follicles cylindric, distinct, 20-35 cm X ca. 7 mm, lenticellate. Seeds sublinear, 1.5-2 cm, coma to 4 cm. Fl. Apr-Aug, fr. Jul-Dec. 2n = 22.
The roots and leaves are used to treat injury and cuts, and the fruits are used to cure pulmonary tuberculosis. A blue dye is extracted from the leaves.
Montane forests, valley thickets; 200-1000 m. Guangdong, Guangxi, Guizhou, Hainan, Yunnan [India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Thailand, Vietnam; N Australia]