Botanical name: Polygonum tortuosum Family: Polygonaceae (Knotweed family)
Synonyms: Aconogonum tortuosum, Polygonum tortuosum var. tibetanum
Twisted Knotweed is an erect subshrub, 1-5 ft tall, branched, velvety to hairy, with elongated rhizome. Stem is round, profusely, dichotomously branched from base or above, velvety to hairy or hairless, woody. Leaves are 1.5-4 cm long, 1-3 cm broad, elliptic, lanceshaped-ovate, pointed or blunt at the tip, margin entire or wacy, ciliate or rough or hairless. Leaves are hairless or velvety on both sides with slightly rough or leathery texture. Leaf-stalks are 0.5-4.0 mm long. Ochrea 5.0-15 mm long, ovate-broadly ovate, entire to dentate, tubular, truncate, hairy. Inflorescences are many flowered, dense, velvety, up to 2 cm long stalked, panicles in leaf axils or at branch ends. Panicles are 1.5-5 cm long. Flowers are 2-3.5 mm across, stalk 1-2.5 mm long, slightly longer in fruit. Ochreolae 1.5-3 mm long, lanceolate, cartilaginous, ciliate, hairy. Tepals are 5, creamy white, nearly equal, 1.5-3.5 x 0.75-1.25 mm, ovate to ovate elliptic, obtuse, entire, parallel veined, veins 3. Stamens 8, subexserted, filaments long, equal. Ovary 0.5-1.5 x about 1.0 mm, oblanceolate, trigonous with three short styles and capitate stigma. Nuts 2.5-4 x 1.5-1.9 mm, ovate, brown, shining, included or slightly exserted from the tepals. Twisted Knotweed is found in the Himalayas, from Afghanistan, N India, Nepal, to SW Asia, at altitudes of 3600-4900 m. Flowering: July-August.
Identification credit: Amit Chauhan
The flower labeled Twisted Knotweed is ...