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.
Flowering May-Oct. Fields, gardens, disturbed sites, often in saline soils; 0-1200 m; introduced; Ariz., Calif., Colo., Fla., Idaho, La., Mass., Mo., Nev., N.Mex., N.C., Tex., Utah, Vt., W.Va.; c Asia.
Duration: Annual Nativity: Non-Native Lifeform: Forb/Herb General: Erect annual 10-60 cm high with simple or moderately branched, finely striate stems. Leaves: Elliptic-lanceolate to oblong, or oblanceolate, 5-20 mm long, 1.5-5 mm wide, acute or rarely obtuse, cuneate at base, glabrous. Stipule sheath 3-6 mm long, lacerate, hyaline to faintly rosaceous. Flowers: In 1-6-flowered axillary fascicles, pedicels 1-4 mm long, calyx 1.5-2 mm long, oblong, greenish with white or pinkish margins, erect, surpassed by achene, 8 stamens, 3 style branches. Fruits: Trigonous achene, 2.2-2.5 mm long, minutely granular-striate, dark brown, dull. Ecology: Found on roadsides and in disturbed habitats from 100-3,500 ft (30-1067 m); flowers April-October. Distribution: Introduced to U.S., from ID, CA, NV, CO south to AZ, east to TX, also in MO, FL, WV, NC, MA, VT ; south to c MEX. Notes: Plant resembles P. ramosissimum but the inflorescences are more spicate. Resembles P. aviculare but that species is prostrate and P. argyrocoleon is upright. Naturalized from central Asia. Ethnobotany: Seeds were parched, ground, and eaten by the Cocopa. Etymology: Polygonum is derived from Greek polys, many, and gonu, knee or joint, while argyrocoleon means silvery and is from the Greek work koleos meaning sheath. Synonyms: None Editor: SBuckley 2010, FSCoburn 2015