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Native Plant Trust: Go Botany Discover thousands of New England plants

Persicaria perfoliata — Asiatic smartweed

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Facts

Asiatic smartweed, also known as "Mile-a-minute weed" for its fast growth rate, is native to East Asia and introduced in North America. It is found in southern New England. The range of this plant has expanded more than 300 miles since its original establishment in a nursery in Pennsylvania, and it is regarded as a plant with serious invasive potential. This vine produces blue-purple, fleshy fruits atop a fused (perfoliate) base of leaves; the fruits are dispersed by animals and water.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Massachusetts
  • New Hampshire
  • Rhode Island
Flower petal color
  • green to brown
  • white
Leaf type
the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
the edge of the leaf blade is entire (has no teeth or lobes)
Flower symmetry
there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
the petals or the sepals are fused into a cup or tube
Stamen number
  • 6
  • 7
  • 8
Fruit type (general)
the fruit is dry but does not split open when ripe
Fruit length
3–3.5 mm
Show all characteristics

  • Clonal plantlets

    Bulbils
    the plant does not appear to have bulbils
    Bulblets replace flowers
    there are no bulblets where the flowers are located

  • Flowers

    Anther opening
    the anthers have narrow slits or furrows that run lengthwise along the anthers
    Anther spurs
    the anthers do not have spurs on them
    Calyx growth after flowering
    the calyx grows to cover or partially cover the fruit
    Calyx symmetry
    there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
    Carpels fused
    the carpels are fused to one another
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament surface
    the filament is smooth, with no hairs or scales
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower petal color
    • green to brown
    • white
    Flower reproductive parts
    • the flower has both pollen- and seed-producing parts
    • the flower has either only pollen- or only seed-producing parts
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is branched above the base
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    • the flower does not have a hypanthium
    • the flower has a hypanthium
    Inflorescence length
    5–12 mm
    Inflorescence one-sided
    the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
    Inflorescence width
    10 mm
    Inner tepals (Rumex)
    NA
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    2–3
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are five petals, sepals, or tepals in the flower
    Number of styles
    3
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Perianth shape
    the perianth is campanulate (bell-shaped, with a tube about as long as wide, flaring at the mouth)
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • green to brown
    • white
    Petal appearance
    • the petals are green and/or leafy in texture
    • the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal tips (Cuscuta)
    NA
    Reproductive system
    all the flowers have both carpels and stamens (synoecious)
    Scales inside corolla
    no
    Sepal and petal color
    the petals and sepals are similar
    Sepal appearance
    the sepals are green or brown, and leaf-like in texture
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal color
    • green to brown
    • white
    Sepal number
    5
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen attachment
    the stamens are not attached to the petals or tepals
    Stamen morphology
    the stamens within each cycle are the same
    Stamen number
    • 6
    • 7
    • 8
    Stamen position relative to petals
    NA
    Stamens fused
    the stamens are not attached to one another
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    NA

  • Fruits or seeds

    Achene relative orientation
    the achenes are perpendicular to the plane of the perianth (vertical)
    Achene shape
    • the achenes are circular in outline
    • the achenes are oval in outline
    Achene surface (Polygonum)
    NA
    Achene type
    the fruit is an achene (dry, indehiscent, and usually one-seeded)
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule ribs
    NA
    Capsule splitting
    NA
    Fruit (pyxis) dehiscence
    NA
    Fruit features (Brassicaceae)
    NA
    Fruit length
    3–3.5 mm
    Fruit locules
    one
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually one-seeded, does not separate or split open at maturity)
    Legumes (Fabaceae)
    NA
    Mericarp length
    0 mm
    Mericarp segment shape (Desmodium)
    NA
    Other markings on berry
    NA
    Ovary stipe
    the ovary or fruit does not have a stipe
    Placenta arrangement
    the plant has basal placentation, where one or a few ovules develop at the base of a simple or compound ovary
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Septum in fruit (Brassicaceae)
    NA
    Wings on fruit
    the fruit does not have wings on it
    prickles on fruits
    the fruits do not have thorn-like defensive structures

  • Glands or sap

    Glands on leaf blade
    the leaf blades do not have glandular dots or scales
    Sap
    the sap is clear and watery
    Sap color
    the sap is clear

  • Growth form

    Growth form
    • the plant is a vine (it cannot support its own weight)
    • the plant is an herb (it has self-supporting stems)
    Horizontal rooting stem
    the plant does not have stolons
    Lifespan
    the plant lives only a single year or less
    Parasitism
    the plant is not parasitic
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    no
    Spines on plant
    there are spines on the plant

  • Leaves

    Bracteole number (Apiaceae)
    0
    Bracts in plantain (Plantago)
    NA
    Final leaf segment length (compound lvs only)
    0 mm
    Final leaf segment length to width ratio (compound lvs only)
    0
    Hairs on underside of leaf
    the underside of the leaf is not hairy, or it has very few hairs
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    the leaf has a distinct leaf stalk (petiole)
    Leaf blade base shape
    • the base of the leaf blade is cordate (heart-shaped, has rounded lobes at the base)
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade length
    40–70 mm
    Leaf blade shape
    the leaf blade is triangular, with the stalk or attachment point on one of the sides
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf duration
    the leaves drop off in winter (or they whither but persist on the plant)
    Leaf form
    the leaves are green, with an expanded blade and a leaf-like texture
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have leaf stalks
    Leaf stalk attachment to leaf
    the petiole attaches at the center of the leaf blade (like an umbrella), or somewhere between the edge and the center
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaf variation
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaflet number
    0
    Leaves per node
    there is one leaf per node along the stem
    Pinnately compound leaf type
    NA
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule features
    • at least some of the stipules on a plant are expanded and with leaf-like color and/or texture at their tips
    • glabrous on the surface
    • the stipules are straight (or somewhat slanted) across the top
    • the stipules do not have tiny hairs (cilia) at their tips
    Stipule fused to leaf stalk
    the stipules are fused to the petioles for some or most of their length
    Stipule shape
    NA
    Stipules
    the plant has stipules

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Massachusetts
    • New Hampshire
    • Rhode Island
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles so that it is roughly circular
    Hair between stem nodes
    the stem has no hairs between the nodes
    Hairs between stem nodes
    the stem has no hairs between the nodes
    Hooked hairs on stem between nodes
    no
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    100–700 cm
    Stem orientation
    NA
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

Connecticut
present
Maine
absent
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
absent

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
not applicable (S-rank: SNA)

From Flora Novae Angliae dichotomous key

15.  Persicaria perfoliata (L.) H. Gross E

Asiatic tearthumb. Ampelygonum perfoliatum (L.) Roberty & Vautier; Polygonum perfoliatum L. • CT, MA, NH, RI. Fields, roadsides, waste areas.

Native to North America?

No

Sometimes confused with

Persicaria arifolia:
sheathing stipules scarious or hyaline, not expanded upward, leaf blades basifixed, and perianth persistent in fruit, but neither thickened nor blue (vs. P. perfoliata, with sheathing stipules apically foliaceous and expanded, leaf blades subpeltate, and perianth persistent in fruit, forming a thickened, blue covering over the achene).
Persicaria sagittata:
sheathing stipules scarious or hyaline, not expanded upward, leaf blades basifixed, and perianth persistent in fruit, but neither thickened nor blue (vs. P. perfoliata, with sheathing stipules apically foliaceous and expanded, leaf blades subpeltate, and perianth persistent in fruit, forming a thickened, blue covering over the achene).

Synonyms

  • Ampelygonum perfoliatum (L.) Roberty & Vautier
  • Polygonum perfoliatum L.

Family

Polygonaceae

Genus

Persicaria