Polygonum ramosissimum |
Polygonum argyrocoleon |
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bushy knotweed, yellow knotweed, yellow-flower knotweed |
Persian knotweed, silver sheath knotweed |
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Habit | Plants yellowish green or bluish green, (dark brown to black after drying in subsp. prolificum), heterophyllous or homophyllous. | Plants green, heterophyllous. | ||||
Stems | erect, usually profusely branched in distal 1/2, not wiry, 10–100(–200) cm. |
erect or decumbent, branched mostly from base, not wiry, 15–100 cm. |
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Leaves | ocrea 6–12(–15) mm, proximal part cylindric, distal part silvery, soon disintegrating into persistent brown fibers; petiole 2–4 mm; blade variable, light yellowish green to bluish green, proximal often caducous, narrowly elliptic, lanceolate, or oblanceolate, rarely ovate, 8–70 × 4–18(–35) mm, margins flat, apex acute to acuminate or obtuse; distal leaves, either overtopping or shorter than or equaling flowers. |
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). |
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Inflorescence(s) | axillary or axillary and terminal, spikelike; cymes uniformly distributed or crowded toward tips of branches, 2–5-flowered. |
axillary and terminal, spikelike; cymes aggregated at tips of stems and branches, 4–6-flowered, bracts inconspicuous. |
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Pedicels | enclosed in or exserted from ocreae, 1–6 mm. |
enclosed in ocreae, 1–2 mm. |
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Flowers | closed; perianth (2–)2.2–3.6(–4) mm; tube 20–38% of perianth length; tepals overlapping, greenish yellow with greenish yellow or yellow, rarely pink or white, margins, petaloid or sepaloid, not keeled, elliptic to oblong, cucullate; midveins thickened or not; stamens 3–6(–8). |
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. |
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Achenes | enclosed in or exserted from perianth, dark brown, ovate, 3-gonous, 1.6–3.5 mm, faces subequal, concave, apex not beaked, edges straight, shiny or dull, usually smooth to roughened, sometimes uniformly or obscurely tubercled; late-season achenes common, 4–15 mm. |
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. |
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Polygonum ramosissimum |
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 |
AR; AZ; CA; CO; CT; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK
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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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Discussion | Subspecies 2 (2 in the flora). Polygonum ramosissimum exhibits considerable morphological complexity and is similar in difficulty to the P. aviculare complex. Further research is necessary to understand the infraspecific variability of this species (M. Costea and F. J. Tardif 2003b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5, p. 551. | FNA vol. 5, p. 560. | ||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Polygonum | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Polygonum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | Michaux: Fl. Bor.-Amer. 1: 237. (1803) | Steudel ex Kunze: Linnaea 20: 17. (1847) | ||||
Web links |
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