Weed Information: Persicaria pensylvanica (smartweed, Pennsylvania)
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Persicaria pensylvanica (smartweed, Pennsylvania)

Family: Polygonaceae

Description

Very similar to ladysthumb (Persicaria maculosa) but without the dark blotch on the leaf and the upper margin of the sheath without cilia. South Dakota Weeds uses the common name of `tanweed` and the scientific name of Polygonum muhlenbergia, but neither name is used elsewhere. The form formerly referred to as Polygonum bicorne is always pink flowered and has either the stamens or styles (but not both) sticking out of the flower.

Characteristics

Flower Color
  • Red (or pink)
  • White
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary spikes
  • Terminal spike
Number of Petals
  • 0 (no petals)
  • 5 petals
Petal Separation
  • United at base only (<25% length)
Petal Tip
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
Flower Width (Head width in the Asteraceae)
  • 1 mm (.04 inch)
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
Number of Sepals
  • sepals lacking
  • 5 sepals
Sepal Separation
  • United at base < 25% length
Sepal Tip
  • Rounded
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 2 styles
  • 3 styles
Number of Stamens
  • 8 stamens
Stamens Attached to the Petals
  • Stamens NOT attached to the petals
Stamens Connate (united)
  • Filaments or anthers NOT united

Carpel Separation
  • Carpels united (or one)
Number of Carpels
  • 2 carpels
  • 3 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Achene
Fruit Length at Maturity
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
Fruit Width at Maturity
  • 1 mm (.04 inch) or less
  • 2 mm (.08 inch)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Membranous, entire
  • Membranous, laciniate
Tendrils
  • Tendrils absent
Venation
  • Pinnate
Petiole (leaf stem) Blade Ratio
  • Petiole < 25% total length
  • Petiole 25% - 75% total length
Leaf Length (blade PLUS petiole)
  • 1 - 2 dm (4.0 - 8.0 inches)
Leaf Width
  • 2 - 4 cm (.80 - 1.6 inches)
Leaf Shape (simple leaves only)
  • Lanceolate
Leaf or Leaflet Margin
  • Entire
Leaf or Leaflet Blade Base
  • Acuminate (attenuate)
Leaf or Leaflet Tip
  • Acuminate (attenuate)
  • Acute
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)
Succulence
  • Not succulent

Milky Juice
  • Juice NOT milky (watery)
Woodiness
  • Herbaceous
Spines or Thorns
  • Spines or Thorns ABSENT
Aromatic (vegetative structures)
  • Not aromatic
Life Cycle
  • Annual
Growth Habit (while flowering)
  • Erect, columnar (narrow)
  • Erect, spherical (bushy)
Plant Height at Maturity
  • 2 - 4 dm (8.0 - 16.0 inches)
  • 4 - 6 dm (1.3 - 2.0 feet)
  • 6 - 8 dm (2.0 - 2.6 feet)
  • 8 - 10 dm (2.6 - 3.3 feet)
  • 1 - 1.5 meters (3.3 - 5.0 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Seasonally saturated
  • Mesic
Chlorophyll
  • Present

Stem Cross Section
  • Round
Flowering Stem Leaves
  • Stem uniformly leafy
Main Stem Branches
  • Main stem branched

Root or Vegetative Propagule
  • Tap Root

US State
  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Kansas
  • Kentucky
  • Louisiana
  • Massachusetts
  • Maine
  • Michigan
  • Missouri
  • Mississippi
  • North Carolina
  • New Hampshire
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • Wisconsin
  • West Virginia
  • Indiana
  • Maryland
  • Rhode Island
  • Vermont
  • Alaska
  • Arizona
  • California
  • Colorado
  • Iowa
  • Minnesota
  • Montana
  • North Dakota
  • New Mexico
  • Nevada
  • Oklahoma
  • Oregon
  • South Dakota
  • Wyoming
  • Nebraska
Other
  • District of Columbia
Canadian Province or Territory
  • New Brunswick
  • Nova Scotia
  • Ontario
  • Quebec
  • Newfoundland

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  • More Turfgrass and Related Weeds: Beyond the Color Atlas, 2011 Clemson University Publishing ISBN# 978-0-9798777-5-9 See Page: 312
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  • Listed as a `Weed` by the Biota of North America Program, 2008 x
  • Listed in the WSSA Composite List of Weeds X
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