Description from
Flora of China
Stellaria alsine var. phaenopetala Handel-Mazzetti; S. alsine var. undulata (Thunberg) Ohwi; S. uliginosa Murray; S. uliginosa var. undulata (Thunberg) Fenzl; S. undulata Thunberg.
Flowers 3--5, in terminal or axillary cymes. Leaves lanceolate to oblong-lanceolate, 5--20 × 2--4 mm. Pedicel slightly declinate in fruit, 0.5--2 cm, slender, glabrous. Capsule ovoid-orbicular, subequaling or slightly longer than persistent sepals, 6-valved. Seeds numerous, brown, reniform, slightly compressed, rugulose.
Fields, streamsides, wetlands; 500--4000 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hunan, Jiangsu, Jiangxi, Nei Mongol, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Japan, Kashmir, Korea, Nepal, Pakistan, Vietnam; Europe].