3. Helicteres angustifolia Linnaeus, Sp. Pl. 2: 963. 1753.
山芝麻 shan zhi ma
Small shrubs, up to 1 m tall. Branchlets gray greenish puberulent. Petiole 5-7 mm; leaf blade narrowly oblong or linear-lanceolate, 3.5-5 × 1.5-2.5 cm, glabrous or nearly so adaxially, gray or yellowish stellate tomentose, or sometimes also hirsute abaxially, base rounded, apex obtuse or acute. Inflorescence cymose, 2- or many-flowered. Pedicel usually with 4 pointed bracteoles. Calyx tube-shaped, ca. 6 mm, stellate puberulent, 5-lobed, lobes triangular. Petals 5, unequal in length, pale blue, pink, or purplish, darker at base of limb, slightly longer than calyx, reflexed at anthesis, uniformly pubescent, claws 2-auriculate. Staminodes linear, very short. Ovary 5-celled, hairy, slightly shorter than style; ovules ca. 10 in each locule. Capsule ovoid-oblong, 12-20 × 7-8 mm, densely setose, setae relatively slender, sparsely hairy, apex acute. Seeds small, brown, with elliptic spots. Fl. almost throughout year.
Sloping grasslands. S Fujian, Guangdong, C and S Guangxi, Hainan, Hunan, Jiangxi, Taiwan, S Yunnan [Cambodia, Indonesia, Japan, Laos, Malaysia, Myanmar, Philippines, Thailand, Vietnam; Australia].
The bark is a source of useful fibers, and the roots and leaves are used medicinally.