Polygonum aviculare subsp. rurivagum

(Jordan ex Boreau) Berher

Fl. Vosges, 195. 1887.

Common names: Narrow-leaf knotweed
Basionym: Polygonum rurivagum Jordan ex Boreau Fl. Centre France ed. 3, 2: 560. 1857
Synonyms: Polygonum aviculare var. angustissimum Meisner Polygonum heterophyllum var. angustissimum (Meisner) Lindman Polygonum heterophyllum subsp. rurivagum (Jordan ex Boreau) Lindman
Treatment appears in FNA Volume 5. Treatment on page 560. Mentioned on page 557.
Revision as of 22:32, 16 December 2019 by FNA>Volume Importer

Plants green, homophyllous to heterophyllous. Stems 1–10, procumbent to ascending, branched at most nodes, proximal branches divaricate, not wiry, 10–40 cm. Leaves: ocrea (6–)8–12 mm, proximal part cylindric, distal part with veins conspicuous, soon disintegrating into persistent fibers; petiole 0.3–2 mm; blade green, lateral veins strongly raised adaxially, narrowly elliptic to linear-lanceolate, (10–)15–27(–30) × 0.5–4.8(–8) mm, (4.5–)5–15(–19) times as long as wide, apex acute; stem leaves 1.2–2.4 times as long as branch leaves. Cymes uniformly distributed along stems and branches, 1–3-flowered. Pedicels enclosed in or exserted from ocreae, 1.5–3 mm. Flowers: perianth 2.2–3.1 mm, 1.6–2.6 times as long as wide; tube 26–40(–42)% of perianth length; tepals often not overlapping, green with pink or red margins, oblong, ± cucullate, outer tepals not pouched at base; veins branched, moderately to strongly thickened; stamens 7–8. Achenes usually exserted from perianth, blackish brown, ovate, 3-gonous, 2.1–2.6(–3) mm, faces subequal or unequal, flat to concave, apex straight, coarsely striate-tubercled; late-season achenes uncommon, 2.5–4 mm. 2n = 60.


Phenology: Flowering Jul–Oct.
Habitat: Disturbed places
Elevation: 0-1000

Distribution

V5 1142-distribution-map.gif

Alta., Man., N.B., Nfld. and Labr. (Nfld.), Que., Sask., Calif., Ind., Iowa, Maine, Mass., N.Y., R.I., S.Dak., W.Va., Europe.

Discussion

Selected References

None.

Lower Taxa

None.
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
(Jordan ex Boreau) Berher +
Polygonum rurivagum +
Narrow-leaf knotweed +
Alta. +, Man. +, N.B. +, Nfld. and Labr. (Nfld.) +, Que. +, Sask. +, Calif. +, Ind. +, Iowa +, Maine +, Mass. +, N.Y. +, R.I. +, S.Dak. +, W.Va. +  and Europe. +
0-1000 +
Disturbed places +
Flowering Jul–Oct. +
Fl. Vosges, +
Weedy +  and Introduced +
Polygonum aviculare var. angustissimum +, Polygonum heterophyllum var. angustissimum +  and Polygonum heterophyllum subsp. rurivagum +
Polygonum aviculare subsp. rurivagum +
Polygonum aviculare +
subspecies +