Polygonum persicaria

Polygonum persicaria

　　Polygonum persicaria

　　Plant morphology: An annual herbaceous plant, 40–80 cm tall. The lower part of the stem lies prostrate, while the upper part is erect or the whole plant may be upright, either unbranched or branched. The ochrea tightly sheathes the stem, with sparse appressed hairs and long marginal hairs along the upper edge; the petioles of the upper stem leaves are extremely short or nearly absent, while those of the lower stem leaves are more distinct and bear stiff bristly hairs; the leaf blades are lanceolate or linear-lanceolate, 4–10 cm long and about 5–20 mm wide, wedge-shaped at the base, long-acuminate at the apex, smooth or sparsely hairy on both surfaces, with stiff bristly hairs on the midrib and margins. The racemes form a panicle, which is terminal or axillary; the peduncle is slightly glandular, the spike is densely flowered, 1.5–5 cm long, rather stout, and erect; the bracts are funnel-shaped, reddish-purple, obliquely acuminate, with sparse marginal hairs, the perianth is pink or white, deeply 5-parted, about 3 mm long, imbricate in arrangement, the stamens are 5–7, usually 6, the pollen grains are spherical, 30 microns in diameter, with reticulate ornamentation; the nut is broadly ovate, flattened or slightly convex on both sides, rarely nearly trigonous, dark brown, glossy, with 2n=22 or 44 chromosomes.

　　It grows in wet areas of forest regions. It is distributed in Heilongjiang and Jilin provinces of China, as well as in various countries across Europe, Asia, Africa, and the Americas.