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Montana Field Guide

Montana Field Guides

Poke Knotweed - Polygonum phytolaccifolium
Other Names:  Aconogonon phytolaccifolium

Native Species

Global Rank: G5
State Rank: S4
C-value: 3

Agency Status


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General Description
Glabrous perennial from a branched, woody caudex. Stems erect, often branched above, 30–90 cm. Leaves petiolate; the blades broadly lanceolate, 5–12 cm long; stipules reddish-brown, glabrous, 1–3 cm long. Flowers 2–4 mm long, numerous in axillary and terminal, leafy-bracted panicles; pedicels 1–4 mm long; tepals green to white. Achene shiny, yellow-brown, 4–7 mm long, 3-winged (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Range Comments
WA to MT, south to CA and NV (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 22

(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)

Well-drained, non-calcareous soil of meadows, open forest, rock slides, usually on warm slopes; subalpine, alpine (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

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:
Poke Knotweed — Polygonum phytolaccifolium.  Montana Field Guide.  .  Retrieved on , from