Polygonum argyrocoleum Steud. ex G. Kunze

Herbs annual. Stems erect, 50-80 cm tall, glabrous, angulate, much branched; branches ascending, fastigiate, nodes inflated, internodes 3-5 cm. Leaves caducous; petiole short, articulate at base; leaf blade usually caducous, lanceolate or linear-lanceolate, 1.5-4 cm × 6-8 mm, both surfaces with conspicuous veins, base narrowly cuneate, apex acute; ocrea lower part brown, upper part white, tubular, membranous, 6-8-veined, lacerate at apex. Inflorescence terminal, spicate, interrupted. Pedicel slender, articulate at apex. Perianth green, margin pinkish or white, 5-parted; tepals elliptic, ca. 2 mm. Stamens 7 or 8; filaments dilated at base. Styles 3; stigmas capitate. Achenes included in persistent perianth, brown, shiny, ovoid, trigonous, 2-2.5 mm, smooth. Fl. Jun-Jul, fr. Jul-Aug.

Plants green, heterophyllous. Stems erect or decumbent, branched mostly from base, not wiry, 15-100 cm. Leaves: ocrea 4-8 mm, proximal part cylindric, distal part soon disintegrating into curly or straight fibers; petiole 0-1.5 mm; blade bluish green, lanceolate or linear-lanceolate, 15-50 × 2-8 mm, margins flat, apex acute; stem leaves 2.1-4 times as long as branch leaves; distal leaves abruptly reduced and not overtopping flowers (shorter than or equaling flowers). Inflorescence axillary and terminal, spikelike; cymes aggregated at tips of stems and branches, 4-6-flowered, bracts inconspicuous. Pedicels enclosed in ocreae, 1-2 mm. Flowers closed; perianth 1.8-2.4 mm; tube 10-22% of perianth length; tepals overlapping, green or white, usually with pink, rarely red or white, margins, petaloid, not keeled, oblong to obovate, cucullate; midveins usually unbranched; stamens 7-8. Achenes enclosed in perianth, brown, ovate, 3-gonous, 1.3-2.3 mm, faces subequal, slightly concave, apex not beaked, with concave edges, shiny, smooth; late-season achenes unknown.

Gansu, Nei Mongol, Qinghai, Xinjiang [Afghanistan, Kazakhstan, Kyrgyzstan, Mongolia, Russia, Tajikistan, Turkmenistan, Uzbekistan; SW Asia].

introduced; Ariz., Calif., Colo., Fla., Idaho, La., Mass., Mo., Nev., N.Mex., N.C., Tex., Utah, Vt., W.Va.; c Asia.

Flowering May-Oct.

Marshy areas, streamsides; 200-2500 m.

Fields, gardens, disturbed sites, often in saline soils; 0-1200m.

Polygonum deciduum is a species of flowering plant in the family Polygonaceae, native to Uzbekistan. It was first described in 1856.

It has also been treated as a synonym of Polygonum argyrocoleon Steud. ex Kunze.