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Platanthera obtusata — blunt-leaved bog-orchid

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Facts

Blunt-leaved bog-orchid has a circumboreal and alpine distribution, and is found in New England from Massachusetts north. This orchid has the distinction of being the only North American plant that is confirmed to be pollinated by mosquitoes, although there may be others.

Habitat

Fens, forests, meadows and fields, swamps

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
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Leaf arrangement
basal: the leaves are growing only at the base of the plant
Number of leaves on stem
  • absent
  • one
Form of lower petal
the labellum does not have a pouch-like shape
Lower petal outline
the labellum is simple in form
Main color of lower petal
  • green to brown
  • white
  • yellow
Nectar spur
the flower has at least one nectar spur on it
Inflorescence type
the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
Lower petal characteristics
  • the labellum has spurs on it
  • the labellum is simple in form
Lower petal length
2.5–10 mm
Show all characteristics
  • Flowers

    Flower petal color
    • green
    • white
    • yellow
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowering date
    • August
    • July
    • June
    Flowers per inflorescence
    2–20
    Form of lower petal
    the labellum does not have a pouch-like shape
    Hairs on inflorescence axis
    the main stem of the inflorescence is hairless
    Inflorescence length
    25–170 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Labellum position
    the labellum is in the lower position on the flower
    Length of narrowed base of lower petal
    0 mm
    Length of peduncle
    100–300 mm
    Lobes at base of lower petal
    0 mm
    Lower petal characteristics
    • the labellum has spurs on it
    • the labellum is simple in form
    Lower petal length
    2.5–10 mm
    Lower petal outline
    the labellum is simple in form
    Lower petal strongly red-veined
    no
    Main color of lower petal
    • green to brown
    • white
    • yellow
    Nectar spur
    the flower has at least one nectar spur on it
    Nectar spur length
    3–10 mm
    Number of stamens
    1
    Orientation of side petals
    the lateral petals are angled steeply upwards
    Pollen sacs
    the pollinia remain intact and do not fragment into smaller parts
    Self-pollinating flowers
    there are no cleistogamous flowers on this plant
    Sepals fused only to sepals
    the sepals are separate from one another
    Shape of viscidium
    the viscidium is roughly circular
    Spots on lower petal
    no
    Spur opening membrane
    there is no membrane over the spur opening
  • Fruits or seeds

    Fruit length
    Up to 10 mm
    Seed capsule orientation
    the capsule points upwards or is angled outwards
  • Growth form

    Plant green or not
    the plant is chlorophyllous (it has green parts)
    Roots
    the rhizomes do not resemble coral
    Underground organs
    • there are only slender roots on the plant
    • this plant has a rhizome (a horizontal underground stem with roots growing from it)
  • Leaves

    Bract relative length
    the bract is shorter than the associated flower
    Features of leaves
    the leaf does not have any of the mentioned special features
    Leaf arrangement
    basal: the leaves are growing only at the base of the plant
    Leaf blade edges
    the edges of the leaf blade have no teeth
    Leaf blade length
    35–150 mm
    Leaf blade length to width ratio
    3–4.4
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
    Leaf blade tip
    the tip of the leaf blade is obtuse (bluntly pointed)
    Leaf blade width
    8–50 mm
    Leaves during flowering
    there are leaves on the plant when it is flowering
    Number of bracts on stem
    0–1
    Number of leaves on stem
    • absent
    • one
  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • fens
    • forests
    • meadows or fields
    • swamps

Wetland status

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

In New England

Distribution

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

Conservation status

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

ssp. obtusata

Massachusetts
historical (S-rank: SH), H (code: H)
New Hampshire
uncommon (S-rank: S3), W (code: W)
Vermont
unrankable (S-rank: SU)

Subspecies and varieties

Our subspecies is Platanthera obtusata (Banks ex Pursh) Lindl. ssp. obtusata.

From Flora Novae Angliae dichotomous key

14.  Platanthera obtusata (Banks ex Pursh) Lindl. ssp. obtusata N

blunt-leaved bog-orchid. Habenaria obtusata (Banks ex Pursh) Richards.; Lysiella obtusata (Banks ex Pursh) Rydb. • MA, ME, NH, VT. Evergreen swamps dominated by Thuja occidentalis, forested fens, wet meadows, evergreen and mixed evergreen-deciduous forests.

Native to North America?

Yes

Sometimes confused with

Platanthera clavellata:
leaves borne on a stem and spur 7-13 mm long (vs. P. obtusata, with leaves all basal and spur mostly 3-8mm long).

Synonyms

  • Habenaria obtusata (Banks ex Pursh) Richards.
  • Lysiella obtusata (Banks ex Pursh) Rydb.

Family

Orchidaceae

Genus

Platanthera