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

Pedicularis canadensis — Canadian lousewort, forest lousewort

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Facts

Forest lousewort is an attractive native perennial that is a hemiparasite (partially parasitic) on grasses and other plants, but will grow in the absence of suitable hosts.

Habitat

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

New England distribution

Adapted from BONAP data

Found this plant? Take a photo and post a sighting.

North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Flower petal color
  • blue to purple
  • pink to red
  • yellow
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 has lobes, or it has both teeth and lobes
Flower symmetry
there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
Number of sepals, petals or tepals
  • there are four petals, sepals, or tepals in the flower
  • there are two 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
4
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
12–16 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 opening
    the anthers have narrow slits or furrows that run cross-wise across the anthers
    Anther tube length
    0 mm
    Calyx growth after flowering
    the calyx does not grow to cover or partially cover the fruit
    Calyx symmetry
    there is only one way to evenly divide the calyx (the calyx is bilaterally symmetrical)
    Carpels fused
    the carpels are fused to one another
    Cilia on petals
    the petal margins do not have cilia
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    • the flower has a concave, hood-like, upper lip
    • the flower has two prominent lips
    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 orientation
    the flower points upwards or is angled outwards
    Flower petal color
    • blue to purple
    • pink to red
    • yellow
    Flower reproductive parts
    the flower has both pollen- and seed-producing parts
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is knob-like at the tip, and unbranched
    Fringed petal edges
    the petals are not fringed
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Hairs on flower stalk
    the flower stalk has hairs on it
    Hairs on inflorescence
    the axis of the inflorescence has hairs entirely without glands
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    the flower does not have a hypanthium
    Hypanthium length
    0 mm
    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
    Interior flower disk
    the flower does not have an interior disc
    Length of flower stalk
    1–6 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
    2
    Number of pistils
    1
    Number of sepals, petals or tepals
    • there are four petals, sepals, or tepals in the flower
    • there are two petals, sepals, or tepals in the flower
    Number of styles
    1
    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)
    • the perianth is cylindric (tube-shaped)
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • blue to purple
    • yellow
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal base
    • NA
    • the petal narrows gradually or does not narrow at the base
    Petal folding in bud
    the petals in bud are arranged in a cycle with edges overlapping like roof shingles (imbricate)
    Petal glandular dots or scales
    no
    Petal hairs (Viola)
    NA
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    18–25 mm
    Petal length relative to sepals
    the petals are longer than the sepals
    Petal nectaries
    the petals do not have nectaries
    Petal number
    2–4
    Petal shape
    the petal outline is another shape
    Petal tip shape
    the petal tip is lobed or fringed
    Petal tips (Cuscuta)
    NA
    Raceme attachment (Veronica)
    NA
    Reproductive system
    all the flowers have both carpels and stamens (synoecious)
    Scales inside corolla
    no
    Sepal and petal color
    the sepals are different from the petals
    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 auricles
    the sepals have no auricles
    Sepal cilia
    the sepals do not have cilia
    Sepal color
    green to brown
    Sepal features
    NA
    Sepal number
    2
    Sepal orientation
    the sepals are pressed against the corolla, or jutting stiffly upward
    Sepal relative length
    the sepal lobes are shorter than the fused portion
    Sepal shape
    the sepal outline is another shape
    Sepal tip shape
    the sepal tip is lobed or fringed
    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
    Spur length
    0 mm
    Spur number
    NA
    Stamen appendages
    stamen appendages are absent
    Stamen attachment
    • the stamens are attached at or near the bases of the petals or tepals
    • the stamens are attached at or near the bases of the petals or tepals
    Stamen lengths differ
    the stamens are didynamous (two long stamens and two short ones)
    Stamen morphology
    the stamens within a cycle differ in length or width
    Stamen number
    4
    Stamen position relative to petals
    NA
    Stamen relative length
    anything
    Stamens fused
    the stamens are not attached to one another
    Staminodes
    there are no staminodes on the flower
    Stigma position
    the stigmas are positioned at the tip of the style
    Style petal-like
    the styles are not petal-like
    Style relative length
    the stigma protrudes beyond the mouth of the corolla
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    the upper lip of the bilabiate corolla has one lobe

  • Fruits or seeds

    Achene relative orientation
    NA
    Achene shape
    NA
    Achene surface (Polygonum)
    NA
    Achene type
    NA
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule ribs
    the capsule has two prominent ribs or wings
    Capsule splitting
    the capsule splits by two main valves, teeth or pores
    Fruit (pyxis) dehiscence
    NA
    Fruit cross-section
    the fruit is at least somewhat flattened
    Fruit features (Brassicaceae)
    NA
    Fruit length
    12–16 mm
    Fruit length relative to sepals
    the fruit is longer than its associated sepals
    Fruit locules
    two
    Fruit shape
    • the fruit is lanceoloid (narrow, widest below the middle and tapering at both ends)
    • the fruit is obloid (longer than wide and with rounded ends)
    Fruit stalk orientation
    the fruits point upward or spread or curve outward
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)
    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
    Ovary stipe length
    0 mm
    Placenta arrangement
    the plant has axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Seeds comose
    no hairs
    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 parasitic on other plants (partially or completely dependent on other plants to supply nutrients)
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    yes
    Spines on plant
    the plant has no spines
    Underground organs
    the plant has a rhizome (a horizontal underground stem with roots growing from it)

  • Leaves

    Bracteole edges
    NA
    Bracteole length
    0 mm
    Bracteole number (Apiaceae)
    0
    Bracteole shape
    NA
    Bracteoles
    there are no bracteoles on the plant
    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
    the floral bracts are green, with a leaf-like texture
    Floral bracts
    the flower has one or more bracts associated with it
    Hairs on leaf stalk
    the petiole has hairs on it
    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 fuzzy or hairy
    • 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)
    Leaf blade base shape
    the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    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 has lobes, or it has both teeth and lobes
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    50–150 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is oblong (rectangular but with rounded ends)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade texture
    the leaf blade is herbaceous (has a leafy texture)
    Leaf blade vein pattern
    the major veins of the leaf blade branch, but do not rejoin
    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
    15–50 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 hair orientation
    • NA
    • the hairs are flat against the leaf surface, mostly pointing towards the leaf tip
    Leaf sheath length
    0 mm
    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 base
    the petiole base is narrow where it attaches to the stem
    Leaf teeth and lobes
    • the leaf blade margin has forward-pointing teeth
    • the leaf blade margin has rounded teeth
    • the leaf has a row of two or more lobes on each side of the central axis
    Leaf tip
    the tip of the leaf blade is acute (sharply pointed)
    Leaf type
    the leaves are simple (i.e., 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 (i.e., lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule edges
    NA
    Stipule features
    NA
    Stipule fused to leaf stalk
    NA
    Stipule length
    0 mm
    Stipule shape
    NA
    Stipules
    there are no stipules on the plant
    Teeth per side of leaf blade
    0

  • Place

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

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Direction of stem hairs
    the hairs point mostly upwards to outwards
    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 hairs between the nodes
    • the stem has no hairs between the nodes
    Hairs between stem nodes
    • the hairs on the stem are plain, without glands or branches, and not tangled
    • 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
    15–40 cm
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem hair distribution
    the hairs on the stem are distributed more of less uniformly
    Stem nodes swollen
    the stem is not swollen at the nodes
    Stem orientation
    the stems are upright or angled outwards
    Stem roughness between nodes
    the stem does not feel rough
    Stem spacing
    the plant is solitary, or a few plants are growing together
    Stem succulence
    the stems are not succulent
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils
    Wings on stem
    the stem does not have wings on it

Wetland status

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

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.

Rhode Island
concern (code: C)

ssp. canadensis

Massachusetts
widespread (S-rank: S5)

ssp. candensis

New Hampshire
uncommon (S-rank: S3), W (code: W)

Subspecies and varieties

Our subspecies is Pedicularis canadensis L. ssp. canadensis.

From Flora Novae Angliae dichotomous key

1.  Pedicularis canadensis L. ssp. canadensis N

forest lousewort. Pedicularis canadensis L. var. dobbsii Fern.; P. gladiata Michx. • CT, MA, ME, 
 NH, RI, VT. Fields, clearings, forest openings, trail edges, woodlands, banks.

Native to North America?

Yes

Sometimes confused with

Pedicularis furbishiae:
calyx with 5 subequal lobes, plants 40–90 cm tall, and capsules ovoid, barely exceeding the persistent calyx (vs. P. canadensis, with calyx with 2 lateral lobes separated by a shallow apical and deep basal sinus, plants 15–40 cm tall, and capsules lanceoloid-obloid, ca. 2 times as long as the persistent calyx).
Rhinanthus minor:
leaf blades toothed and flowers 9-15 mm long (vs. P. canadensis, with leaf blades lobed and flowers 18-25 mm long).

Synonyms

  • Pedicularis canadensis var. dobbsii Fern.
  • Pedicularis gladiata Michx.

Family

Orobanchaceae

Genus

Pedicularis