Knotweed

The rhizome is used for making tea and used in the same way as that of the following species, Bistorta amplexicaulis.

Densely tufted, 10-25 cm high, glabrous with woody rootstock, perennial, branched herb. Leaves basal as well as cauline, sessile or shortly petiolate. Basal leaves 3.25-6.0 x 1.0-2.0 cm, elliptic to ovate or obovate, subsessile to petiolate, obtuse to acute, crenulate, glaucous beneath; cauline leaves few, 2.5-4.0 x 0.8-1.2 cm, narrowly lanceolate to lanceolate, obtuse to acute. Ochrea 4-10 mm long, tubular, brown with prominent veins. Inflorescence a pedunculate, 2-4 cm spicate head. Ochreolae ovate-obovate, 2.5-4 x 2-3 mm,. Flowers pedicellate, 2.5-3.0 (-3.5) mm across. Pedicel 2-3 mm long. Tepals 5, biseriate, pink, 3-4 x 1-2 mm, elliptic, obtuse to acute. Stamens 8, biseriate, inner series with long filaments. Ovary trigonous with free and long styles, stigma rounded. Nuts 2-2.5 x 1-2 mm, trigonous, dark brown, smooth and shining.

Subshrubs 10-15 cm tall. Rhizomes horizontal, ligneous. Branches densely tufted, terete, herbaceous, glabrous. Basal leaves shortly petiolate; leaf blade gray-green abaxially, green adaxially, oblanceolate or lanceolate, 5-10 × 1-1.8 cm, subleathery, both surfaces glabrous, midvein large, base narrowly cuneate, margin revolute, apex acute. Cauline leaves subsessile, smaller; ocrea brown, tubular, ca. 1 cm, membranous, veins numerous, glabrous, apex oblique, not ciliate, usually lacerate. Inflorescence terminal, spicate, erect, dense, large, 3-6 cm, 1-1.5 cm in diam.; bracts ovate, membranous. Pedicels longer than perianth. Perianth purple-red, 5-parted; tepals obovate, ca. 4 mm. Stamens 8; anthers purple. Styles 3, connate at base; stigmas capitate. Achenes included in persistent perianth, dark brown, shiny, ellipsoid, trigonous, ca. 3 mm, base narrowly cuneate, apex acute. Fl. Jul-Aug, fr. Aug-Sep.

Afghanistan, Himalaya (Kashmir to Nepal), Tibet.

Distribution: Pakistan (Himalayas, Hindukush), India, Nepal and Western Myanmar.

Xizang [NW India, Kashmir, Nepal, Pakistan, Sikkim].

3500-4800 m

Fl. Per.: June-September.

A common alpine and subalpine species, grows on open slopes, edges and rocky places on higher altitudes from 3000-4800 m, quite variable especially in the habit, leaf and peduncle length. On the higher altitudes, the plant tends to become semiprostrate to ± cushion-like with erect floral axis. However, this variation seems to be ± continuous or clinal in nature.

Grassy slopes, rocky fissures; 4000-4900 m.

Polygonum affine D. Don, Prodr., Fl. Nep. 70. 1825; Hook. f., Fl. Brit. Ind. 5: 33. 1886; Schiman-Czeika & Rech.f. in Rech.f., Fl. Iran. 56: 62. 1968; R. R. Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 202. 1972; Bhopal & Chaudhri in Pak. Syst. 1(2): 80. 1977; Polygonum donianum Spreng. Syst. 4: 154. 1827; P. brunonis Wall. in Royle, Ill. Bot. Himal. Mount. 317. t. 80. 1839; Persicaria affinis (D. Don) Ronse Decr. in Bot. J. Linn. Soc. 98. 368. 1988.

Bistorta affinis (D. Don) Greene; Persicaria affinis (D. Don) Ronse Decraene; Polygonum donianum Sprengel.