(L.) H. Gross
Description
Persicaria chinensis (L.) H. Gross is a widespread, often weedy perennial of warm-temperate to subtropical Asia, now naturalised well beyond its native range. GBIF records over 12,500 occurrences spanning China, Taiwan, Japan, India, Nepal, Thailand, Myanmar, the Malesian archipelago and the Philippines, with introduced populations in Australia, New Zealand, Réunion, the United States and Jamaica. It favours moist, disturbed ground, forest margins, roadside banks, streamsides and clearings from the lowlands to mid-montane elevations. The Bhutanese plant photographed at Galephug, at about 600 m in October, reflects its abundance in the humid foothill belt of the eastern Himalaya.
The plant is a sprawling to scrambling herb with branched, often reddish stems that are swollen at the nodes and sheathed by membranous ochreae characteristic of the family. The leaves are ovate to ovate-lanceolate, frequently with a dark chevron-shaped marking, and taper to an acute apex. The inflorescence comprises numerous small, capitate clusters of flowers; the perianth is white to pinkish and five-lobed, becoming fleshy and bluish-black in fruit. The fruit is a trigonous achene enclosed by the persistent, juicy perianth, which gives the fruiting heads a berry-like appearance.
Segregated by some authors as Polygonum chinense, the taxon is morphologically variable, and several varieties and forms have been recognised across its vast range. Its fleshy fruiting perianth promotes endozoochorous dispersal by birds, contributing to its colonising success and to its status as an invasive in several introduced territories. The species is of no conservation concern; rather, its broad ecological amplitude and ready establishment on disturbed soils make it one of the more conspicuous and adaptable knotweeds of monsoonal Asia.
Author: (L.) H. Gross · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, Hara & Williams Polygonaceae treatments