Polygonum aviculare subsp. boreale

(Lange) Karlsson

Svensk Bot. Tidskr. 91: 249. 1998.

Common names: Northern knotweed
Weedy
Basionym: Polygonum aviculare var. boreale Lange Consp. Fl. Groenland. 1: 105. 1880
Synonyms: Polygonum arenastrum subsp. boreale (Lange) Á. Löve Polygonum boreale Lindman Polygonum heterophyllum subsp. boreale (Lange) Á. Löve & D. Löve
Treatment appears in FNA Volume 5. Treatment on page 557. Mentioned on page 556.
Revision as of 10:09, 30 July 2020 by imported>Volume Importer
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Plants green, homophyllous or subheterophyllous. Stems 1–7, prostrate to ascending, mostly branching from base, 6–50 (–90) cm. Leaves: ocrea 3.5–7 mm, proximal part cylindric to funnelform, distal part soon disintegrating, nearly completely deciduous; petiole 7–9 mm; blade green, lateral-veins visible but not raised abaxially, obovate-spatulate or oblanceolate, (12.5–) 16–44 (–55) × (4–) 6–18 (–22) mm, 2–4 (–5.5) times as long as wide, apex obtuse to rounded; stem-leaves (1.1–) 1.3–2.5 (–3) times as long as branch leaves. Cymes uniformly distributed, rarely crowded at tips of stems and branches, (3–) 4–7-flowered. Pedicels mostly exserted from ocreae, 2–5 mm. Flowers: perianth 3.3–5.5 mm, 1.6–2.8 times as long as wide; tube 25–35 (–39) % of perianth length; tepals overlapping, green with white or pink margins, obovate, flat or curved outward in fruit, outer tepals not pouched at base; veins branched, thickened; stamens 6–8. Achenes enclosed in perianth, dark-brown, ovate, 3-gonous, (2.5–) 2.7–4 (–4.2) mm, faces subequal, concave, apex straight, coarsely striate-tubercled; late-season achenes uncommon, 4–5 mm. 2n = 40.


Phenology: Flowering Aug–Oct.
Habitat: Sandy, gravelly, or rocky coastal areas
Elevation: 0-500 m

Distribution

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Greenland, Nfld. and Labr. (Labr.), nw Europe

Discussion

Selected References

None.

Lower Taxa

None.

"/2" is not declared as a valid unit of measurement for this property.

0.4 cm4 mm <br />0.004 m <br /> - 0.42 cm4.2 mm <br />0.0042 m <br /> +
exserted +  and included +
dull +  and shiny +
smooth;roughened +
3-gonous +  and ovate +
whitish yellow +
elliptic +  and oblong +
striate-tubercled +
straight +
obtuse;rounded +
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
- Lange Karlsson +
not stipelike +
Polygonum aviculare var. boreale +
5 cm50 mm <br />0.05 m <br /> - 6 cm60 mm <br />0.06 m <br /> +
0.6 cm6 mm <br />0.006 m <br /> - 5 cm50 mm <br />0.05 m <br /> +
spatulate;obovate;spatulate;obovate;elliptic;lanceolate;elliptic +
coriaceous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> - 2.2 cm22 mm <br />0.022 m <br /> +
foliaceous +  and perfoliate +
scale-like +
just below the soil surface or and above the soil surface +  and spreading +
Northern knotweed +
- 3-4-7-flowered +
crowded +  and distributed +
hyaline +  and silvery +
Greenland +, Nfld. and Labr. - Labr. +  and nw Europe +
tubercled +  and striate-tubercled +
concave +
0-500 m +
concave +
subequal +
persistent +
adnate +, free +  and distinct +
disarticulating +  and solid +
decumbent to erect +  and prostrate +
unwinged +  and winged +
black +, red +, brown +  and yellowish +
exserted +  and included +
pubescent +  and glabrous +
spheroidal +, 4-gonous +, lenticular +, biconvex +, discoid +, 3-gonous +  and 2-gonous +
Sandy, gravelly, or rocky coastal areas +
compound +, branched +  and simple +
nonmembranous +
0.4 cm4 mm <br />0.004 m <br /> - 0.5 cm5 mm <br />0.005 m <br /> +
sessile +  and petiolate +
deciduous +
pink +  and white +
pubescent +  and glabrous +
lobed +, undulate +, crisped +, crenulate +  and entire +
unbranched +  and branched +
not +  and thickened +
swollen +
silvery +, white +  and hyaline +
disintegrating +
deciduous +  and persistent +
0.35 cm3.5 mm <br />0.0035 m <br /> - 0.7 cm7 mm <br />0.007 m <br /> +
coriaceous +  and membranous +
somewhat larger +
anatropous +, , +  and orthotropous +
erect;spreading +
accrescent +
0.2 cm2 mm <br />0.002 m <br /> - 0.5 cm5 mm <br />0.005 m <br /> +
spreading;erect +
greenish white;pink +
campanulate +  and urceolate +
nonaccrescent +
0.33 cm3.3 mm <br />0.0033 m <br /> - 0.55 cm5.5 mm <br />0.0055 m <br /> +
fleshy +, indurate +  and membranous +
0.7 cm7 mm <br />0.007 m <br /> - 0.9 cm9 mm <br />0.009 m <br /> +
Flowering Aug–Oct. +
- 2-3 - -4-carpellate +
Svensk Bot. Tidskr. +
slender;stout +
woody +  and fibrous +
6 +  and 8 +
- 1.1-1.3-2.5 - -3 times as long as branch leaves +
50 cm500 mm <br />0.5 m <br /> - 90 cm900 mm <br />0.9 m <br /> +
flexuous +
prostrate +  and ascending +
1 +  and 7 +
papillous-scabridulous +
6 cm60 mm <br />0.06 m <br /> - 50 cm500 mm <br />0.5 m <br /> +
2 +  and 3 +
penicillate +, fimbriate +  and capitate +
deciduous +  and persistent +
2-lobed +  and cylindric +
coriaceous +  and membranous +
connate +  and distinct +
spreading;erect +
Polygonum arenastrum subsp. boreale +, Polygonum boreale +  and Polygonum heterophyllum subsp. boreale +
Polygonum aviculare subsp. boreale +
Polygonum aviculare +
subspecies +
overlapping +
connate +  and distinct +
obovate +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
subheterophyllous +  and homophyllous +
not cushionlike +