Polygonum linicola (O. Schwarz) Sutul. - Pale Persicaria.

Systematic position.

Family Polygonaceae Juss., genus Polygonum L.


Polygonum lapathifolium subsp. linicola (Sutul.) Tzvel., Persicaria linicola (Sutul.) Nenjuk., Persicaria linicola Sutul.

Biological group.

Spring annual weed.

Morphology and biology.

Stem 40-60 cm in height, simple, glabrous, with extended internodes. Leaves lanceolate, narrowed at both apices with short cilia along margins, 3-7 cm in length, 5-13 mm in width; their petioles 3 to 15 mm in length. Young leaves covered with thin felt from below, grayish; adult leaves completely glabrous. Sheaths narrow, tightly enveloping stalk, with short sparse cilia along margin. Bunches rather thick, upright, 1-2 cm in length. Flower pedicles always without joints. Flowers greenish-white or pink, without glandules. Nutlets reddish-black, glabrous, shining, flat, with exavations on sides, pointed at tip, 2-2.5 mm in length. Blossoms July until September. Seed germination, flowering, and fructification are rather rapid in Pale Persicaria. The vegetation period is very short. After maturing, the fruits do not fall due to absence of pedicle joints. The weed biology and development are concurrent with those of flax; in the shape of its extending and poorly branching stalk, the plant imitates external appearance of cultural plants; the seed shape and size are very similar to those in flax; seed weight is 2.8-4.4 mg in Pale Persicaria, and 3.44 to 4.65 mg in flax; therefore, seeds of the weed are almost inseparable from the flax seeds. Since the weed seeds are not shed from plants, they are almost entirely threshed together with flax, littering grain.


In the territory of the former USSR, the species is distributed in the European part and Western Siberia (Turinsk district).


The weed grows in crops of long-stalked flax mainly, less often in other cultures.

Economic significance.

This is a weed of spring grain cereals, less often of vegetables and potato, being a specialized weed of long-stalked flax. Control measures are cleaning of sowing material, crop rotation, application of herbicides.

Reference citations:

Keller B.A., ed. 1934. Weed plants of the USSR. V. 2. Leningrad: AN SSSR, 244 p. (in Russian).
Komarov V.L., ed. 1936. Flora of the USSR. V. 5. Moscow & Leningrad: AN SSSR. 762 p. (in Russian).

© Nadtochii I.N.

Picture © Nadtochii I.N.

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