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Montana Field Guides

Scatter Knotweed - Polygonum spergulariiforme
Other Names:  Polygonum douglasii ssp. spergulariiforme

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Status Under Review
Native Species

Global Rank: G5T5
State Rank: SU

Agency Status


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General Description
Stems erect, branched, up to 50 cm tall, usually papillose-scabridulous. Petioles up to 2 mm long. Ochrea 8-12 mm long, cylindrical below but fragmenting into fibers above. Leaves 35-60 long, lanceolate, apex actue or mucronate. Inflorescences lateral or terminal, spike-like, dense, 2-5-flowered. Flowers open or only partially open; perianth 3-5 mm long, tepals oblong-obovate, overlapping, petaloid, pink or white. Achenes 3-5 mm long, black, shiny, smooth to striate-tubercled (adopted from: Costea, Tardif & Hinds, 2005, in Flora N. American Vol. 5).

Range Comments
Native to the Pacific Coast of North America with a few additional records from ID, MT and WY. Montana collections over 100 years old from Yellowstone and Meaghre counties (Kartesz in prep. 2012).

Moist or dry areas (Dorn 2001, Vascular Plants of Wyoming, 3rd Ed.).

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.
    • Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
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Citation for data on this website:
Scatter Knotweed — Polygonum spergulariiforme.  Montana Field Guide.  .  Retrieved on , from