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Montana Field Guide

Montana Field Guides

White-margin Knotweed - Polygonum polygaloides

Native Species

Global Rank: G4G5
State Rank: S3S4
C-value: 4

Agency Status


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General Description
Annual. Stems erect or ascending, 4-angled, simple or branched at the base, 1–5 cm. Leaves sessile, 5–20 mm long, linear; stipules glabrous, 2–5 mm long. Flowers 1–3 mm long, axillary and in a dense, terminal, bracteate raceme; bracts linear to ovate; pedicels 0–2 mm long; tepals white to rose with a green midrib. Achene 3-sided, 1–3 mm long, shiny or dull brown (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Flowering in July, fruiting in August.

Range Comments
BC to SK south to CA, AZ, NM (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Moist, sparsely vegetated soil, often around ponds in the valleys and montane zone.

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus bifarius, Bombus flavifrons, Bombus frigidus, Bombus melanopygus, Bombus sylvicola, Bombus occidentalis, Bombus pensylvanicus, Bombus insularis, and Bombus kirbiellus (Macior 1974, Colla and Dumesh 2010).

  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141:39-68.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
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Citation for data on this website:
White-margin Knotweed — Polygonum polygaloides.  Montana Field Guide.  .  Retrieved on , from