Description from
Flora of China
Polygonum filiforme Thunberg in Murray, Syst. Veg., ed. 14, 377. 1784; Persicaria filiformis (Thunberg) Nakai; Polygonum virginianum Linnaeus var. filiforme (Thunberg) Nakai; P. virginianum f. glabratum Matsuda; Sunania filiformis (Thunberg) Rafinesque; Tovara filiformis (Thunberg) Nakai; T. ryukyuensis Masamune; T. virginiana (Linnaeus) Rafinesque var. filiformis (Thunberg) Steward.
Leaves broadly elliptic to ovate, both surfaces appressed hispid, base cuneate, apex shortly acuminate or acute. Fl. Aug-Oct, fr. Sep-Nov.
Forests on mountain slopes, valleys; 100-2500 m. Anhui, Fujian, S Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, S Shaanxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Korea, Myanmar, Russia (Far East)].