Description from Flora of China
Lindernia angustifolia (Bentham) Wettstein; Vandellia angustifolia Bentham.
Annuals, to 40 cm tall. Roots fibrous, abundant. Stems usually erect, striate, glabrous; branches few to numerous, ascending, striate, glabrous. Leaves sessile, linear to linear-lanceolate, 1-4 cm X 2-8 mm, glabrous, margin entire or somewhat irregularly serrate; main veins 3-5, parallel. Flowers axillary, solitary. Pedicel to 3.5 cm in fruit, striate, glabrous. Calyx ca. 2.5 mm, to 4 mm in fruit, lobed to base; lobes narrowly lanceolate, glabrous. Corolla purple, blue-purple, or white, ca. 6.5 mm; lower lip slightly longer than upper, spreading flat, 3-lobed; upper lip 2-lobed. Filaments of anterior stamens with a linear appendage; posterior anthers with connective of lower locule produced into a long tail equalling locule. Style persistent. Capsule linear, to 1.4 cm, more than 2 X as long as persistent calyx. Seeds brownish, oblong. Fl. May-Oct, fr. Jul-Nov.
Rice fields, along rivers, wet areas; ca. 1500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Jiangsu, Jiangxi, Henan, Hubei, Hunan, Yunnan, Zhejiang [Cambodia, India, Indonesia (Java), Japan, S Korea, Laos, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam].