Polygonum pubescens Blume, Bijdr. 1825-26; Steward in Contr. Gray Herb. 88: 62. 1930; Polygonum hydropiper var. acuminata Franch. & Sav. Enum. Pl. Jap. 2: 474. 1877; P. flacidum var. hispida Hook. f., Fl. Brit. Ind. 5: 40. 1886. excl. syn.; P. hydropiper var. hispidum (Hook. f.) Steward in Contr. Gray Herb. 88: 60. 1930; P. flaccidum auct. non Roxb., Meisn. in DC. Prodr. 14 (1): 107. 1856; Hook. f., Fl. Brit. Ind. 5: 39. 1886; P. hydropiper subsp. microcarpum Danser in Bull. Jard. B. Buitenzorg, Ser. 3, 8: 188. 1927; P. hydropiper var. flaccidum (Meisn.) Steward in Contr. Gray Herb. 88: 59. 1930; Persicaria pubescens (Blume) Hara var. acuminata (Franch. & Sav.) Hara in Fl. E. Himal. 74. 1966; P. hydropiper subsp. microcarpa (Danser) Sojak in Preslia 46: 153. 1974; P. hydropiper (L.) Spach subsp. flaccida (Meisn.) Munshi et Javeid, Syst. Stud. Polygon. Kashm. Himal. 76. 1986.

Very similar to Persicaria hydropiper (L.) Spach but usually much taller and with longer and larger leaves, up to 15 cm long, ochreae strigose, 10-15 mm long with much longer 8-10 mm long cilia. Spikes up to 15 cm long, filiform, which are rather drooping, extremely slender and much interrupted. Ochreolae glabrous-glandular with ciliate mouth. Perianth ± gland-dotted. Stamens always 8. Nuts trigonous.

Fl. Per.: June-August.

Type: Described from the top of Burangrang mountain.

Grows from plains to 1500 m in or near water; Distribution: Himalayas, Pakistan, Nepal, India, Bangla Desh, extending up to Fareast.