Persicaria pubescens (Blume) Hara

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.

Herbs annual (?perennial). Stems erect, often reddish, 60-90 cm tall, sparsely hispidulous, branched above, swollen at nodes. Leaves without peppery taste; petiole 4-7 mm, densely hispidulous; leaf blade ovate-lanceolate or broadly lanceolate, 5-10 × 1-2.5 cm, both surfaces densely hispidulous, base broadly cuneate, margin ciliate, apex acuminate or acute; ocrea tubular, 1-1.5 cm, membranous, hispid, apex truncate, stoutly long ciliate. Inflorescence terminal or axillary, spicate, pendulous, lax, 7-15 cm, interrupted below; bracts green, funnel-shaped, margin submembranous, ciliate, each 3- or 4-flowered. Pedicels longer than bracts, slender. Perianth green, red above, 5-parted, densely purplish glandular punctate; tepals elliptic, 3-4 mm. Stamens 8, included. Styles 3, connate to below middle. Achenes included in persistent perianth, black, dull, ovoid, trigonous, 2.5-3 mm, densely pitted. Fl. Aug-Sep, fr. Sep-Oct.

Distribution: Himalayas, Pakistan, Nepal, India, Bangla Desh, extending up to Fareast.

Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning (Dalian), Shaanxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [Bhutan, India, Indonesia, Japan, Korea, Sikkim].

Fl. Per.: June-August.

Grows from plains to 1500 m in or near water.

Along ditches, water sides, field margins; sea level to 2700 m.

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.

Persicaria flaccida (Meisner) H. Gross; P. hydropiper (Linnaeus) Spach subsp. flaccida (Meisner) Munshi & Javeid; P. pubescens (Blume) H. Hara; Polygonum donii Meisner; P. flaccidum Meisner; P. flaccidum var. hispidum (Buchanan-Hamilton ex D. Don) J. D. Hooker; P. hispidum Buchanan-Hamilton ex D. Don; P. hydropiper var. flaccidum (Meisner) Steward; P. hydropiper var. hispidum (Buchanan-Hamilton ex D. Don) Steward; P. oryzetorum Blume.