Polygonum argyrocoleon |
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Persian knotweed, silver sheath knotweed |
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Habit | 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. |
Polygonum argyrocoleon |
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Phenology | Flowering May–Oct. |
Habitat | Fields, gardens, disturbed sites, often in saline soils |
Elevation | 0-1200 m (0-3900 ft) |
Distribution |
AZ; CA; CO; FL; ID; LA; MA; MO; NC; NM; NV; TX; UT; VT; WV; c Asia [Introduced in North America]
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Source | FNA vol. 5, p. 560. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Polygonum |
Sibling taxa | |
Name authority | Steudel ex Kunze: Linnaea 20: 17. (1847) |
Web links |