Spergula japonica Swartz, Ges. Naturf. Freunde Berlin Neue Schriften 3: 164. 1801.

Herbs annual or biennial. Stems tufted, suberect or creeping, 5--20 cm tall, slender, basally branched, apically glandular hairy. Leaves linear, 5--20 × 0.8--1.5 mm, glabrous, connate at base, acute and minutely spine tipped. Flower solitary, terminal or axillary. Pedicel erect, 1--2 cm, sparsely pubescent. Sepals 5, ovate-elliptic, ca. 2 mm, glandular hairy, apex obtuse. Petals 5, ovate, slightly shorter than sepals, apex rounded. Stamens 5. Ovary ovoid; styles 5. Capsule globose, slightly longer than sepals, 5-valved. Seeds brown, reniform-globose, not grooved, sharply tuberculate. Fl. Apr--May, fr. May--Jun. 2n = 46, 64.

This species is used medicinally.

Sandy riversides, uncultivated farmland, roadside grasslands, forests, streamsides, floodlands; (100--)600--1900(--4000) m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Japan, Korea, Nepal, Russia, Sikkim].