Polygonum erectum — upright knotweed

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 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
  • pink to red
  • white
  • yellow

  Flower reproductive parts

  the flower has both pollen- and 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 flower has two or more completely separate styles
  • the style is branched above the base

  Fused stamen clusters

  NA

  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 one-sided

  the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks

  Inner tepals (Rumex)

  NA

  Nectar spur

  the flower has no nectar spurs

  Number of pistils

  1

  Number of sepals, petals or tepals

  there are five petals, sepals, or tepals in the flower

  Number of styles

  2–3

  Ovary position

  the ovary is above the point of petal and/or sepal attachment

  Petal and sepal arrangement

  the flower includes two cycles of petal- or sepal-like structures

  Petal and sepal colors

  • green to brown
  • pink to red
  • white
  • yellow

  Petal appearance

  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
  • the petals of the flower have folds or plaits on them

  Petal hairs (Viola)

  NA

  Petal number

  5

  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 resemble petals in color and texture

  Sepal appendages

  the sepals do not have appendages on them

  Sepal appendages (Oenothera)

  NA

  Sepal color

  • green to brown
  • pink to red
  • white

  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 a cycle differ in length or width

  Stamen number

  8

  Stamen position relative to petals

  NA

  Stamens fused

  the stamens are not attached to one another

  Stigma position

  the stigmas are positioned at the tip of the style

  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 another shape in outline

  Achene surface (Polygonum)

  the achene has tiny rounded bumps or projections on it as well as parallel lines or ridges (striate-papillose)

  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

  2.3–3.5 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 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

  the plant has no spines

• 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

  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 rounded

  Leaf blade edges

  the edge of the leaf blade is entire (has no teeth or lobes)

  Leaf blade length

  30–80 mm

  Leaf blade shape

  • the leaf blade is elliptic (widest near the middle and tapering at both ends)
  • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)

  Leaf blade surface colors

  the upper side of the leaf blade is relatively uniform in color

  Leaf blade width

  8–25 mm

  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 teeth and lobes

  the edge of the leaf blade is entire (has no teeth or lobes)

  Leaf type

  the leaves are simple (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 (lobed or unlobed but not separated into leaflets)

  Stipels

  NA

  Stipule edges

  • the stipule margins do not have teeth
  • the stipule margins have teeth on them

  Stipule features

  • glabrous on the surface
  • the stipules have two lobes at their tips

  Stipule shape

  the stipules are tubular (cylindrical and hollow)

  Stipules

  the plant has stipules

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • shores of rivers or lakes

• 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

  15–75 cm

  Tendril origin

  NA

  Tendrils

  the plant does not have tendrils

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

From Flora Novae Angliae dichotomous key