Epilobium formosanum Masamune
Clumped erect perennial herb, with leafy soboles; stems (9-) 15-70 cm tall, usually very branched, strigillose, lacking raised lines through internodes. Leaves 1-4.5 cm long, 0.15-0.5 cm wide, sublinear to narrowly lanceolate, weakly denticulate, on petioles 1-4 mm long. Flowers erect; floral tube 0.6-0.8 mm long; sepals 2.5-3.2 mm long; petals 3-5 mm long, white, pink, or rarely rose-purple; stigma capitate or broadly clavate. Capsules 23-50 mm long, glabrescent or sparsely strigillose, on pedicels 8-22 mm long. Seeds 0.8-0.9 mm long, the surface coarsely papillose; coma dingy white, easily detaching. 2n=36. Flowers Aug-Oct; fruit Sep-Nov.
TAIPEI: Tongshan, Suzuki s. n. 1933. ILAN: Nanshan, Hsu 5801; Mt. Taiheizan, Suzuki s. n. 1928. HSINCHU: Tapachienshan, Chang 2008, Kuoh 3222. MIAOLI: Kuanwu, Peng 8412. TAICHUNG: Lishan, Kao 5007. NANTOU: Citou to Cidi, Kuoh 3664; Chiti to Yanshan, Kao 7246. CHIAYI: Mt. Rokurinzan, Chuang & Kao s. n. 1957; Mt. Niitaka, Sasaki s. n. 1924. TAITUNG: Kucihu, Hsu 3289; Shunshan Wushan, Hosokawa s. n. 1932. HUALIEN: Tayuling, Hsu & Hsu 3767, Chuang & Kao 4454.
Distribution: Japan and E China to N Philippines. Found in the northern two thirds of Taiwan, growing on wet, often disturbed grassy slopes and along streams and rivers in mountains; (400-) 1,000-2,000 (-3,500) m.