Vern.: Chukladan.

Polygonum alpinum All., Auct. Synop. Method. Strip. Hort. Reg. Taur. 4: 94. 1773; Fl. Pedem. 2: 206. t. 68. f. 1. 1785; Hook. f., Fl. Brit. Ind. 5: 49. 1886; Coode & Cullen in P.H.Davis, Fl. Turk. 2: 271, 1966; P. weyrichii F. Schmidt var. alpinum Maxim. ex Feash. et Sav., Enum. Pl. Jap. 2: 402. 1875; Persicaria alpina (All.) H. Gross in Bull. Geogr. Bot. 23: 31. 1913; Pleuropteropyrum alpinum (All.) Kitagawa, Neo-Lineam. Fl. Manschur. 295. 1937; Munshi & Javeid, l.c. 78; Polygonum angustifolium Pall., Reise Russ. Reich. 3: 230. 1776; Persicaria angustifolia (Pallas) Ronse Decr. in Bot. J. Linn. Soc. 98: 367. 1988; Aconogonon alpinum var. stewartii S.-P. Hong, l.c. 81.

Erect, 70-120 (-180) cm tall, branched perennial herb, branches few, flexuous, glabrescent to pubescent or glabrous with few hairs below the node. Leaves shortly petiolate, petiole 1.5-8 mm long, pubescent or glabrous, lamina 5-13 x 1-3.5 cm, lanceolate or lanceolate-ovate, acuminate to mucronate at the apex, attenuate to cuneate at the base, densely pubescent to woolly tomentose below, glabrous or sparsely pubescent above; ochrea truncate, membranous, 1.2-2.6 cm long. Inflorescence a simple or well branched terminal panicle, 6-16 cm long. Ochreolae truncate, membranous. Bracts ovate, obtuse 0.75-1 x 0.5-0.6 mm. Flowers pedicellate, pedicel glabrous, 0.6-1.7 mm long, articulate. Tepals 5, subequal, creamy white or sometimes light yellow, 1.5-3 (-3.5) x 0.8-1.5 mm, slightly accrescent in the fruit. Stamens 8, ovary trigonous, styles 3, very short; stigmas capitate. Nuts trigonous, exserted beyond the tepals, 3-4 (-4.5) x 1.6-2.8 mm, ± dark brown, glossy.

Fl. Per.: June-August.

Lectotype: Described from N. Italy; Piedmont, Formazza valley, Anonymous (TO).

A highly variable species especially in the degree of pubescence on the leaves and stem which vary from densely hairy to almost glabrous. However the variation seems to be continuous. S.-P. Hong (l.c.) recognized var. stewartii on the basis of dull whitish tomentum on the lower side of the leaves. This character is not correlated with any other character. Grows between 2000-4000 m in open meadows, shady slopes; Distribution: North America, Spain, Russian Turkestan, Siberia and North Western Himalayas.