Polygonum erectum |
Polygonum parryi |
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devil's shoestring, erect knotweed, renouée dressée, upright knotweed, wireweed |
Parry's knotweed, Parry's or prickly knotweed, prickly knotweed |
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Habit | Plants light green or yellowish, heterophyllous. | Herbs, compact, often cushion-like. |
Stems | erect to ascending, sparingly branched in distal 1/2, not wiry, 15–75 cm. |
erect, green-brown, simple or branched from base, not wiry, 2–5(–8) cm, glabrous. |
Leaves | ocrea 7–12 mm, proximal part cylindric, distal part usually persistent, with strong veins, margins entire or lacerate, silvery, later disintegrating into ± persistent brown fibers; petiole 1–5 mm; blade light green or yellowish, elliptic to obovate, 30–60(–80) × (8–)10–25 mm, margins flat, apex obtuse; stem leaves 1.5–3.5(–4) times longer than branch leaves; distal leaves overtopping flowers in distal part of inflorescence. |
± uniformly distributed, dense, not articulated to ocreae, basal leaves ± persistent, distal leaves gradually reduced to bracts; ocrea 2–4(–5) mm, glabrous, proximal part cylindric, distal part deeply lacerate, disintegrating into white, curled fibers; petiole absent; blade 3-veined, without pleats, linear-lanceolate, subulate, 5–13(–20) × 0.4–1 mm, margins revolute, smooth, apex spine-tipped. |
Inflorescences | axillary; cymes in axils of most leaves and toward tips of stems and branchs, 1–5-flowered. |
axillary; cymes in most axils, 1-flowered. |
Pedicels | mostly exserted from ocreae, 3–7 mm. |
absent. |
Flowers | closed; perianth 2.8–3.8(–4.2) mm; tube 20–37% of perianth length; tepals overlapping, green with yellowish, rarely whitish green, margins, sepaloid, not keeled, oblong to obovate, cucullate; midveins branched, moderately to heavily thickened; stamens 7–8. |
closed; perianth 1.5–2(–2.5) mm; tube 6–15% of perianth length; tepals overlapping, usually reddish with white margins, petaloid, oblong, navicular, apex acute; midveins unbranched; stamens 8. |
Achenes | enclosed in perianth, brown to tan, ovate, 3-gonous, 2.3–3.5 mm, faces subequal, ± concave, apex not beaked, edges concave, dull, striate-tubercled; late-season achenes uncommon, 4–5 mm. |
slightly exserted from perianth at maturity, dark brown, ovate, 1.2–1.6(–2) mm, faces subequal, shiny, smooth. |
Polygonum erectum |
Polygonum parryi |
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Phenology | Flowering May–Oct. | Flowering May–July. |
Habitat | Dry, waste ground | Vernally moist, open, sandy or rocky places |
Elevation | 10-300 m (0-1000 ft) | 500-2000 m (1600-6600 ft) |
Distribution |
AL; AR; CO; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; VA; VT; WA; WI; WV; WY; AB; ON; QC; SK
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CA; WA
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Discussion | Polygonum erectum was cultivated in the midwest by Native Americans for its starchy seeds (C. M. Scarry 1993). It was formerly confused with P. achoreum (T. R. Mertens and P. H. Raven 1965). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 5, p. 550. | FNA vol. 5, p. 563. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Polygonum | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia |
Sibling taxa | ||
Name authority | Linnaeus: Sp. Pl. 1: 363. (1753) | Greene: Bull. Torrey Bot. Club 8: 99. (1881) |
Web links |
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