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Dotted Smartweed - Polygonum punctatum
Other Names:  Persicaria punctata

Native Species

Global Rank: G5
State Rank: S3S4
(see State Rank Reason below)
C-value: 4

Agency Status


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State Rank Reason (see State Rank above)
Polygonum punctatum is known from about five counties. This species may be easily mis-identified or undercollected. More data on population sizes and distributions is needed before warranting it as a Species of Concern.
  • Details on Status Ranking and Review
    Dotted Smartweed (Polygonum punctatum) Conservation Status Review
    Review Date = 11/14/2016
    View State Conservation Rank Criteria
    Population Size

    ScoreU - Unknown

    Range Extent

    ScoreF - 20,000-200,000 sq km (~8,000-80,000 sq mi)

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    Number of Populations

    ScoreB - 6 - 20

    Number of Occurrences or Percent Area with Good Viability / Ecological Integrity

    ScoreB - Very few (1-3) occurrences with excellent or good viability or ecological integrity

    Environmental Specificity

    ScoreD - Broad. Generalist or community with all key requirements common

    Long-term Trend

    ScoreU - Unknown


    ScoreU - Unknown


    ScoreU - Unknown

    CommentThreats: Unknown/undetermined.

    Intrinsic Vulnerability

    ScoreC - Not intrinsically vulnerable

General Description
Plants: Rhizomatous-stoloniferous perennials (McGregor et al. 1986), glandular-punctate. Stems upright to prostrate or decumbent and rooting at the nodes, somewhat branched, up to 1 meter in length (Hitchcock et al. 1964).

Leaves: Short-petiolate; the blades with or without a central dark blotch, lanceolate to oblanceolate (Lesica 2012), (3)5-10(12) cm in length (Hitchcock et al. 1964), up to 2 cm in width, acuminate (McGregor et al. 1986), glandular-punctate and ciliate, otherwise usually smooth (Hitchcock et al. 1964); stipules (ocreae) brown and papery (Lesica 2012), enveloping the stem obliquely, 10-15 mm in length, typically with a few appressed hairs and several marginal bristles (Hitchcock et al. 1964).

Inflorescence: Flowers in erect or arching (McGregor et al. 1986), narrow, terminal and typically 2 to a few lateral racemes; racemes up to 10 cm in length (Hitchcock et al. 1964); flower clusters interrupted, particularly below, not crowded, the groups of flowers subtended by sheathing bracts (ocreolae) (McGregor et al. 1986); pedicels 1–4 mm in length, ascending (Lesica 2012).

(Lesica’s contribution adapted from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)

Flowers July-October (McGregor et al. 1964).

Diagnostic Characteristics
Dotted Smartweed is distinguished almost entirely on its darker, shinier seeds from the similar Marshpepper Smartweed (Polygonum hydropiper), which has dull brown seeds. As other species are recognized to have dimorphic seeds, the natural separation of these two species is questionable (Hitchcock et al. 1964). Douglas et al. (1999) adds that, unlike Dotted Smartweed with its usually 5-lobed perianths and interrupted racemes, Marshpepper Smartweed has mostly 4-lobed perianths, and racemes that are barely interrupted.

Range Comments
Throughout temperate and tropical North America, S. America (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Mud along margins of streams, wetlands; plains, valleys (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).

Reproductive Characteristics
Flowers: Flowers typically extended beyond the involucres; perianth 3-3.5 mm in length, the tepals unequal, ovate to oblong, densely glandular-punctate, joined for nearly half their length, greenish with white or pink margins; stamens 8, styles 2-3, free or attached together basally, shy of 0.5 mm in length (Hitchcock et al. 1964).

Fruit: Achene lenticular or 3-sided (Hitchcock et al. 1964), not winged, 2–3 mm long, shiny dark brown to black (Lesica 2012).

(Lesica’s contribution adapted from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)

  • 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.
    • Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1964. Vascular Plants of the Pacific Northwest. Part 2: Salicaceae to Saxifragaceae. University of Washington Press, Seattle. 597 pp.
    • 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.
    • McGregor, R.L. (coordinator), T.M. Barkley, R.E. Brooks, and E.K. Schofield (eds). 1986. Flora of the Great Plains: Great Plains Flora Association. Lawrence, KS: Univ. Press Kansas. 1392 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Britton, N. L. and A. B. Brown. 1913. An Illustrated Flora of the Northern United States, Canada, and the British Possessions. 2nd Edition in 3 Volumes. New York, NY: Charles Scribner's Sons. B13BRI01PAUS.
    • 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:
Dotted Smartweed — Polygonum punctatum.  Montana Field Guide.  .  Retrieved on , from