8. Persicaria hydropiper (L.) Spach, Hist. Veg. 10: 536. 1841; Hara in Fl. East. Himal. 2: 23. 1971; in Hara et al. Enum. Fl. Pl. Nepal 3: 176. 1982; Grierson & D.G.Long, Fl. Bhutan 1: 162. 1983; Munshi & Javeid, l.c. 75. (Fig.6, A-E).
Polygonum hydropiper L., Sp. Pl. 361. 1753; Hook. f., Fl. Brit. Ind. 5: 39. 1886; excl. var. eglandulosa Hook.f.; Kitamura, Pl. W. Pak. & Afgh. 44. 1964; D.A.Webb & Chater in Tutin et al., Fl. Europ. 1:79. 1964; Coode & Cullen in P.H.Davis, Fl. Turk. 2: 274. 1966; Schiman-Czeika & Rech. f. in Rech. f., Fl. Iran. 56: 60. 1968; R.R.Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 1: 206. 1977; P. korrense Nakai in Bot. Mag. Tokyo 33: 6. 1919; Nakai in Mor. Enum. Pl. Cor. 132. 1922.
Erect, 30-45 (-50) cm high with tufted roots branched from base or above, or sometime simple, annual to perennial herb. Stem glabrous, brown, sometimes shining. Leaves 1.5-8 (-10) x 0.4-1.5 (-2) cm, linear lanceolate to lanceolate, acuminate, margin ciliate, surface glabrous or scabrous or slightly pubescent beneath on the midrib and reddish punctate gland-dotted on both surfaces, petiole 0.2-0.4 cm long. Ochreae 0.25-1.5 (-2.0) cm long, glabrous, ciliae at the mouth of ochrea 1-4 mm long. Inflorescence 3-7 cm long, lax, flowers ± distant, erect, not drooping pedunculate raceme; peduncles 1.0-6.5 cm long. Flowers 1.0-2.0 mm across, pedicellate; pedicel 0.5-1.25 mm long. Ochreolae 1.0-2.0 mm long, ovate, dentate-entire, gland-dotted. Tepals 5, pink, 1.0-3.0 x 0.75-1.5 mm, obovate, obtuse, red gland-dotted. Stamens 6, filaments long, unequal. Ovary 0.5-1.5 x 0.5-0.75 mm, trigonous, elliptic with 3 or sometimes 2 styles united in the upper half, then free; stigma capitate. Nuts 2.5-3.5 (-4) x 1.5-2.0 mm, mostly trigonous, sometimes biconvex within the same raceme, dark brownish, pubescent.
Fl. Per.: April-September.
Type: Described from Europe, Herb. Linn 510.9 (LINN).
A fairly common and widespread species, grows in ditches, on banks and moist shady places from plains to 2000 m. Easily recognized by its red glandular punctate leaves and red glandular perianth and interrupted racemes. Nuts are variable. Trigonous and biconvex nuts are sometimes found within the same raceme; Distribution: Widely distributed in N. W. Africa, Temperate Asia, Pakistan, India, extending to far east up to Japan, N. America.
