Polygonum aviculare subsp. aviculare

Common names: Common knotweed
WeedyIntroducedIllustrated
Synonyms: Polygonum aviculare var. eximium (Lindman) Ascherson & Graebner Polygonum aviculare subsp. heterophyllum (Thiébaut-de-Berneaud ex Persoon) Arcangeli Polygonum aviculare subsp. monspeliense Polygonum aviculare var. vegetum Ledebour Polygonum heterophyllum Polygonum monspeliense
Treatment appears in FNA Volume 5. Treatment on page 557. Mentioned on page 558.

Plants green, heterophyllous (often lacking larger proximal stem leaves at maturity). Stems 1–3, ascending or erect, sometimes decumbent, basal branches divaricate, (10–)25–75(–100) cm. Leaves: ocrea (5.5–)6–10(–14) mm, proximal part cylindric, distal part silvery, hyaline, soon lacerate and disintegrating into fibers; petiole 1–6(–8) mm; blade green, lateral veins visible but not raised abaxially, elliptic to oblanceolate, 18–50(–60) × (6–)10–20 mm, 2–4.5 times as long as wide, apex acute or obtuse; stem leaves 1.4–4 times as long as branch leaves. Cymes aggregated at tips of stems and branches, 3–8-flowered. Pedicels mostly exserted from ocreae, 2–5 mm. Flowers: perianth (2.3–)2.8–4.7(–5) mm, 1.8–2.8 times as long as wide; tube (15–)20–37% of perianth length; tepals overlapping, green with pink, red, or white margins, oblong, flat (cucullate in fruit), outer tepals not pouched at base; veins branched, thickened; stamens 7–8. Achenes enclosed in or barely exserted from perianth, brown to dark brown, ovate, 3-gonous, (2.1–)2.7–3.7 mm, faces subequal, concave, apex straight, striate-tubercled; late-season achenes uncommon, 3.5–5 mm. 2n = 40, 60.


Phenology: Flowering May–Oct.
Habitat: Fields, uncultivated areas, waste places, roadsides
Elevation: 0-3500 m

Distribution

V5 1137-distribution-map.gif

Introduced; St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon, Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., La., Maine, Md., Mass., Mich., Minn., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., Wyo., Eurasia.

Discussion

Selected References

None.

Lower Taxa

None.
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
Linnaeus +
Common knotweed +
St. Pierre and Miquelon +, Alta. +, B.C. +, Man. +, N.B. +, Nfld. and Labr. (Nfld.) +, N.W.T. +, N.S. +, Ont. +, P.E.I. +, Que. +, Sask. +, Yukon +, Ala. +, Alaska +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Okla. +, Oreg. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Vt. +, Va. +, Wash. +, Wyo. +  and Eurasia. +
0-3500 m +
Fields, uncultivated areas, waste places, roadsides +
Flowering May–Oct. +
Weedy +, Introduced +  and Illustrated +
Polygonum aviculare var. eximium +, Polygonum aviculare subsp. heterophyllum +, Polygonum aviculare subsp. monspeliense +, Polygonum aviculare var. vegetum +, Polygonum heterophyllum +  and Polygonum monspeliense +
Polygonum aviculare subsp. aviculare +
Polygonum aviculare +
subspecies +