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enable glossary links

black bindweed, climbing bindweed, climbing knotweed, Eurasian black bindweed, ivy bindweed

giant knotweed, giant wing-knotweed, Sakhalin knotweed

Habit Herbs, annual, not rhizomatous, 0.5–1 m. Herbs, perennial, rhizomatous, 2–4(–5) m.
Stems

scandent or sprawling, branched proximally, herbaceous, puberulent, sometimes mealy, not glaucous.

usually clustered, erect, sparingly branched, herbaceous, stiff, glabrous, glaucous.

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.

ocrea persistent or deciduous, brownish, cylindric, 6–12 mm, margins oblique, face without reflexed and slender bristles at base, otherwise glabrous or puberulent;

petiole 1–4 cm, glabrous;

blade ovate-oblong, 15–30(–40) × 7–25 cm, base cordate, margins entire, glabrous or scabrous to ciliate, apex obtuse to acute, abaxial face minutely dotted, glaucous, with hairs along veins distinctly multicellular, 0.2–0.6 mm, tips acute to acuminate, adaxial face glabrous.

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.

axillary, mostly distal, erect or spreading, paniclelike, 3–8 cm, axes puberulent to pubescent;

peduncle 0.1–4 cm or absent, puberulent to reddish-pubescent.

Pedicels

ascending or spreading, articulated distally, 1–3 mm, glabrous or, rarely, scabrid.

ascending or spreading, articulated proximal to middle, 2–4 mm, glabrous.

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.

bisexual or pistillate, 4–7 per ocreate fascicle;

perianth accrescent in fruit, greenish, 4.5–6.5 mm including stipelike base, glabrous;

tepals obovate to elliptic, apex obtuse to acute, outer 3 winged;

stamens 6–8;

filaments flattened proximally, glabrous;

styles connate basally;

stigmas fimbriate.

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.

included, brown, 2.8–4.5 × 1.1–1.8 mm, shiny, smooth; fruiting perianth glabrous, wings flat to undulate, 1.8–2.2 mm wide at maturity, decurrent on stipelike base to articulation, margins entire.

2n

= 40.

= 44, 66, 102, 132 (Japan, Korea).

Fallopia convolvulus

Fallopia sachalinensis

Phenology Flowering May–Oct. Flowering Jul–Oct.
Habitat Cultivated ground, waste places Disturbed places
Elevation 0-2700 m (0-8900 ft) 0-500 m (0-1600 ft)
Distribution
from FNA
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]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CT; DE; ID; IL; KY; LA; MA; MD; ME; MI; MT; NC; NJ; NY; OH; OR; PA; RI; TN; VA; VT; WA; WI; WV; BC; NB; NF; NS; ON; PE; QC; Asia (Japan) [Introduced in North America; introduced in Europe]
[WildflowerSearch map]
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.)

Fallopia sachalinensis was introduced as a soil binder and garden ornamental. Like F. japonica, it spreads aggressively and has been declared noxious in California, Oregon, and Washington. It hybridizes with F. japonica, yielding F. ×bohemica. The mid-stem inflorescences of F. sachalinensis usually are shorter than the subtending leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 5, p. 545. FNA vol. 5, p. 542.
Parent taxa Polygonaceae > subfam. Polygonoideae > Fallopia Polygonaceae > subfam. Polygonoideae > Fallopia
Sibling taxa
F. baldschuanica, F. cilinodis, F. dumetorum, F. japonica, F. sachalinensis, F. scandens, F. ×bohemica
F. baldschuanica, F. cilinodis, F. convolvulus, F. dumetorum, F. japonica, F. scandens, F. ×bohemica
Synonyms Polygonum convolvulus, Bilderdykia convolvulus, F. convolvulus var. subalata, Reynoutria convolvulus, Tiniaria convolvulus Polygonum sachalinense, Reynoutria sachalinensis, Tiniaria sachalinensis
Name authority (Linnaeus) Á. Löve: Taxon 29: 300. (1970) (F. Schmidt) Ronse Decraene: Bot. J. Linn. Soc. 98: 369. (1988)
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