Fallopia convolvulus |
Fallopia japonica |
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black bindweed, climbing bindweed, climbing knotweed, Eurasian black bindweed, ivy bindweed |
Japanese knotweed, Japanese wing-knotweed |
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Habit | Herbs, annual, not rhizomatous, 0.5–1 m. | |
Stems | scandent or sprawling, branched proximally, herbaceous, puberulent, sometimes mealy, not glaucous. |
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Leaves | ocrea persistent or deciduous, tan or greenish brown, cylindric, 2–4 mm, margins oblique, face not fringed with reflexed hairs and slender bristles at base, otherwise glabrous or scabrid; petiole 0.5–5 cm, puberulent in lines; blade cordate-ovate, cordate-hastate, or sagittate, 2–6(–15) × 2–5(–10) cm, base cordate, margins wavy, scabrid, apex acuminate, abaxial face usually mealy and, rarely, minutely dotted, not glaucous, adaxial face glabrous. |
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Inflorescences | axillary, erect or spreading, spikelike, 2–10(–15) cm, axes puberulent; peduncle 0.1–10 cm or absent, glabrous or scabrid distally in lines. |
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Pedicels | ascending or spreading, articulated distally, 1–3 mm, glabrous or, rarely, scabrid. |
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Flowers | bisexual, 3–6 per ocreate fascicle; perianth nonaccrescent, greenish white, often with pinkish or purplish base, 3–5 mm including stipelike base, glabrous or outer 3 with blunt, hyaline hairs; tepals elliptic to obovate, apex obtuse to acute, outer 3 obscurely keeled; stamens 8; filaments flattened proximally, glabrous; styles connate distally; stigmas capitate. |
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Achenes | included, black, 4–5(–6) × 1.8–2.3 mm, dull, minutely granular-tuberculate, especially on faces; fruiting perianth glabrous or with blunt, hyaline hairs, wings absent or, rarely, flat to undulate, 0.4–0.9 mm wide at maturity, scarcely decurrent on stipelike base, margins entire. |
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2n | = 40. |
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Fallopia convolvulus |
Fallopia japonica |
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Phenology | Flowering May–Oct. | |
Habitat | Cultivated ground, waste places | |
Elevation | 0-2700 m [0-8900 ft] | |
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; 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; NL; NS; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia [Introduced in North America; introduced in South America (Argentina, Chile), Africa (Algeria, Morocco, Republic of South Africa), Pacific Islands (Hawaii, New Zealand), Australia]
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AK; AR; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; SD; TN; UT; VA; VT; WA; WI; WV; BC; MB; NB; NF; NS; ON; PE; QC [Asia, introduced in Europe]
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Discussion | Fallopia convolvulus can be an aggressive weed in crop fields. Rare plants with winged fruiting perianths have been named var. subalata; that characteristic often varies within populations. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 4 (1 in the flora). Fallopia japonica is planted widely as a garden ornamental; it has a proclivity to escape and spread aggressively. Once established, plants can be difficult to eradicate because of their extensive, woody rhizomes. The species has been declared noxious in Alabama, California, Oregon, Vermont, and Washington. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 545. | FNA vol. 5, p. 543. |
Parent taxa | ||
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Polygonum convolvulus, Bilderdykia convolvulus, F. convolvulus var. subalata, Reynoutria convolvulus, Tiniaria convolvulus | Reynoutria japonica |
Name authority | (Linnaeus) Á. Löve: Taxon 29: 300. (1970) | (Houttuyn) Ronse Decraene: Bot. J. Linn. Soc. 98: 369. (1988) |
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