Tasteless Water Pepper

Foodplant / gall
embedded sorus of Bauhinus cordae causes gall of live, swollen, deformed ovary of Persicaria laxiflora

Foodplant / pathogen
sorus of Sphacelotheca hydropiperis infects and damages live ovary of Persicaria laxiflora
Remarks: season: 8-9

Erect to suberect, 35-60 cm tall, branched, annual herb. Stem branched from base or above, glabrous. Leaves 2-8.0 x 0.3-2.0 cm, shortly petioled, linear lanceolate, acute, margin, veins and midrib ciliate, sparsely reddish glandular below. Ochreae 1.0-1.5 cm long, tubular, ciliate, ± appressed hirsute, cilia at the mouth of the tube almost equalling the ochreae. Inflorescence, 1-5 cm long, slender, terminal to axillary, often drooping raceme. Flowers 1.5-2.5 mm across, pedicel 0.5-1 mm long. Ochreolae 1.0-2.0 mm long, tubular, reddish-purplish, ciliate-aristate, ciliae or aristae 1-2 mm long. Tepals 5, 1.25-2.5 x 0.5-1.5 cm, oblanceolate, obtuse, biseriate, unequal, pink. Stamens 8, filaments long, inserted below middle, equal. Ovary small, lanceolate, trigonous, with three styles, free in the upper half, stigmas capitate. Nuts biconvex to appressed, 1.5-3.0 x 0.5-1.5 mm, dark brown to almost black, glabrous, lustrous.

Africa, Europe, W. Asia, Himalaya, Tibet, east to China and Japan, N. America.

Distribution: Himalayas, Europe, N. W. Africa, temperate Asia and North America.

500 m

Fl. Per.: July-October.

A fairly common species, grows between 2500-10000 ft in moist areas, along water channels. Very close to Persicaria hydropiper but differs by having eglandular perianth and often drooping spikes which are often terminal and cilia as long as the ochreal tube. Differs from P. tenella by having distinctly biconvex to appressed nuts and reddish glands on the leaves. Our plants differ from European and N.W.African specimens by having smaller flowers and smaller nuts and may represent a separate geographical race.

Polygonum mite Schrank, Baier. Fl. 668. 1789; D.A.Webb & Chater in Tutin et al., Fl. Europ. 1: 79. 1964; Schiman-Czeika & Rech.f. in Rech.f., Fl. Iran. 56: 61. 1968; R. R. Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 211. 1972; P. hydropiper L. var. eglandulosa Hook. f., Fl. Brit. Ind. 5: 39. 1886; Persicaria hydropiper subsp. mite (Schrank) A. Majeed & Kak in J. Bomb. Nat. Hist. Soc. 517. 1984; Persicaria hydropiper subsp. mite (Schrank) Munshi et Javeid, l.c. 75. 1986. comb. illegit.

Persicaria mitis (Schrank) Assenov is a species of flowering plant in the family Polygonaceae, native to Europe. (Persicaria mitis Delarbre is a different species, being a rejected synonym of Persicaria maculosa.)