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

Rumex obtusifolius — bitter dock

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Facts

Larger and with broader leaves than curly dock, bitter dock is another widespread introduced weed with broad habitat tolerances from wetlands to roadsides and waste places.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Flower petal color
  • green to brown
  • pink to red
Leaf type
the leaves are simple (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 six 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
Stem nodes swollen
the stem is swollen at the nodes
Fruit type (general)
the fruit is dry but does not split open when ripe
Fruit length
2–2.7 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 attachment
    the anther is attached by its base to the filament
    Anther color
    the anthers show no hint of a pink, reddish or purplish tint
    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 number
    10–25
    Flower petal color
    • green to brown
    • pink to red
    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
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Hairs on inflorescence
    the axis of the inflorescence has no hairs on it
    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)
    • one of the inner tepals has a tubercle
    • the margins of the inner tepals have teeth or spines on them
    • two or three of the inner tepals have tubercles
    Length of flower stalk
    2.5–10 mm
    Marks on petals
    there are no noticeable marks on the petals
    Nectar spur
    the flower has no nectar spurs
    Number of branches in umbel
    0
    Number of carpels
    3
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are six 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
    • pink to red
    Petal appearance
    the petals are green and/or leafy in texture
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    3–6 mm
    Petal number
    3
    Petal shape
    • the petal outline is ovate (widest below the middle and broadly tapering at both ends)
    • the petal outline is roughly triangular
    Petal tip shape
    • the petal tip is acute (sharply pointed)
    • the petal tip is obtuse (bluntly pointed)
    Petal tips (Cuscuta)
    NA
    Petal width
    2–3.5 mm
    Raceme attachment (Veronica)
    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
    • pink to red
    Sepal number
    3
    Sepal texture
    the sepals are either very thin but flexible, like a membrane, or they are leaf-like in texture
    Sepal uniformity
    all the sepals are about the same size
    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 number
    6
    Stamens fused
    the stamens are not attached to one another
    Staminodes
    there are no staminodes on the flower
    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 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
    Carpel beak length
    0 mm
    Fruit (pyxis) dehiscence
    NA
    Fruit cross-section
    the fruit is roughly triangular in cross-section
    Fruit features (Brassicaceae)
    NA
    Fruit length
    2–2.7 mm
    Fruit length relative to sepals
    the fruit is shorter than its associated sepals
    Fruit locules
    one
    Fruit shape
    the fruit is ovoid (egg-shaped)
    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)
    Fruit width
    1.2–1.7 mm
    Hair type on fruit
    NA
    Hairs on fruit
    the fruits are not hairy
    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
    • the ovary or fruit has 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
    Seed number
    1
    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 more than two years
    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
    Underground organs
    • the plant has a caudex (the root mass is firm and hardened at the top)
    • there is a thickened taproot 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
    Final leaf segment width (compound lvs only)
    0 mm
    Floral bract texture
    NA
    Floral bracts
    the flower does not have bracts
    Flower bract length
    0 mm
    Hairs on underside of leaf
    • the underside of the leaf is fuzzy or hairy
    • the underside of the leaf is not hairy, or it has very few hairs
    Hairs on upper side of leaf
    the upper side of the leaf is not hairy, or it has very few hairs
    Hooked hairs on underside of leaf
    no
    Inflated hairs on leaf
    the leaf blade does not have inflated hairs on it
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    • the leaf has a distinct leaf stalk (petiole)
    • the leaf has no stalk
    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 rounded
    Leaf blade base symmetry
    the leaf blade base is symmetrical
    Leaf blade bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade length
    200–400 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is oblong (rectangular but with rounded ends)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade vein pattern
    the major veins form a net-like pattern due to splitting and rejoining
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip (it may or may not have secondary veins)
    Leaf blade width
    100–150 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 shiny
    the upper side of the leaf is dull or slightly shiny
    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 basal margin of the leaf blade
    Leaf stalk length
    Up to 120 mm
    Leaf teeth and lobes
    • the edge of the leaf blade is entire (has no teeth or lobes)
    • the leaf blade margin is wavy, but does not have teeth
    Leaf tip
    • the tip of the leaf blade is acute (sharply pointed)
    • the tip of the leaf blade is obtuse (bluntly pointed)
    Leaf type
    the leaves are simple (lobed or unlobed but not separated into leaflets)
    Leaf types
    There is a gradual change in appearance of the leaves from the base (or near the base) of the plant to those from further up on the stem, with leaves progressively changing as one moves higher on the stem (often becoming shorter, or less toothed/lobed, and/or with shorter petioles).
    Leaf variation
    the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
    Leaflet number
    0
    Leaflet petiolules
    NA
    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 features
    • glabrous on the surface
    • the stipules do not have tiny hairs (cilia) at their tips
    Stipule shape
    the stipules are tubular (cylindrical and hollow)
    Stipules
    the plant has stipules
    Teeth per side of leaf blade
    0

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
    • shores of rivers or lakes

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Direction of stem hairs
    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
    Length of hairs between stem nodes
    0 mm
    Plant height
    60–150 cm
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem hair distribution
    NA
    Stem nodes swollen
    the stem is swollen at the nodes
    Stem orientation
    the stems are upright or angled outwards
    Stem roughness between nodes
    the stem does not feel rough
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils
    Wings on stem
    the stem does not have wings on it

Wetland status

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

In New England

Distribution

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

Conservation status

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

Massachusetts
unranked (S-rank: SNR)

Subspecies and varieties

Our subspecies is Rumex obtusifolius L. ssp. obtusifolius.

From Flora Novae Angliae dichotomous key

10.  Rumex obtusifolius L. ssp. obtusifolius E

bitter dock. Acetosa oblongifolia (L.) A. & D. Löve; Rumex obtusifolius L. ssp. agrestis (Fries) Danser • CT, MA, ME, NH, RI, VT. Fields, roadsides, waste areas, shorelines. Two subspecies of this plant are known to occur in North America. Subspecies obtusifolius is marked by a perianth with a single tubercle and prominent, marginal teeth. Subspecies sylvestris Čelak is marked by a perianth with 3 tubercles and short marginal teeth (sometimes the teeth essentially absent). The latter subspecies is rare in North America and is not known to occur in New England. However, North American authors have traditionally not recognized these different forms and, therefore, the distribution of ssp. sylvestris is poorly known.

6×10. Rumex crispus × Rumex obtusifolius → Rumex ×‌pratensis Mert. & Koch is a rare, partially sterile, hybrid dock known from MA, ME, NH, RI, VT. Its sterility manifests as fruiting perianths of different shapes and sizes on the same plant. The hybrid has inner tepals with very small teeth along the margins mostly shorter than 0.8 mm tall and leaf blades that are mostly 2–4 times as long as wide, which is intermediate between the parents (mostly 3.2–5.8 times as long as wide in R. crispus; mostly 1.2–2.8 times as long as wide in R. obtusifolius). Length to width measurements should be performed on the larger leaf blades.

8×10. Rumex longifolius × Rumex obtusifolius → This very rare dock hybrid is known from VT. It shows very small teeth on the margins of the inner tepals mostly shorter than 0.8 mm tall. It was found growing with both parents.

Native to North America?

No

Sometimes confused with

Rumex brittanica:
larger, veiny-patterned parts of the flower without teeth along the margin, all 3 of them with a distinct tubercle near the center (vs. R. obtusifolius, with larger, veiny-patterned parts of the flower with marginal teeth, only 1 of which with a tubercle near the center).
Rumex crispus:
larger, veiny-patterned parts of the flower without teeth along the margin, usually all 3 of them with a distinct tubercle near the center (vs. R. obtusifolius, with larger, veiny-patterned parts of the flower with marginal teeth, only 1 of which with a tubercle near the center).

Synonyms

  • Acetosa oblongifolia (L.) A. & D. Löve
  • Rumex obtusifolius ssp. agrestis (Fries) Danser

Family

Polygonaceae

Genus

Rumex