Platanthera orbiculata (Pursh) Lindl.

round-leaved bog-orchid

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Round-leaved bog-orchid is known to be pollinated by at least two species of noctuid moths in North America. When the moth inserts its proboscis into the nectar spur, its head comes into contact with one of the pollinia, which attaches to the moth's compound eye. This species may be confused with large-leaved bog-orchid (Platanthera macrophylla).

Habitat

Forests, swamps

Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf arrangement
basal: the leaves are growing only at the base of the plant
Number of leaves on stem
absent
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
white
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
7–17 mm
Show All Characteristics
  • Flowers
    Flower petal color
    • green
    • white
    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
    3–27
    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
    50–200 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Inflorescence width
    40–50 mm
    Labellum position
    the labellum is in the lower position on the flower
    Length of flower stalk
    6–13 mm
    Length of narrowed base of lower petal
    0 mm
    Length of peduncle
    150–520 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
    7–17 mm
    Lower petal outline
    the labellum is simple in form
    Lower petal strongly red-veined
    no
    Main color of lower petal
    white
    Nectar spur
    the flower has at least one nectar spur on it
    Nectar spur length
    14–27 mm
    Number of stamens
    1
    Orientation of side petals
    • the lateral petals are vertically oriented or nearly so
    • the lateral petals slant outward
    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
    15–20 mm
    Fruit width
    4–6 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
    • the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms
    • there are only slender roots on the plant
  • Leaves
    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
    50–210 mm
    Leaf blade length to width ratio
    1–1.7
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is orbicular (roughly circular, as wide as long)
    • the leaf is a shape other than those described
    Leaf blade tip
    the tip of the leaf blade is obtuse (bluntly pointed)
    Leaf blade width
    30–220 mm
    Leaves during flowering
    there are leaves on the plant when it is flowering
    Number of bracts on stem
    0–6
    Number of leaves on stem
    absent
  • Place
    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • forests
    • swamps

Wetland Status

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

New England Distribution and Conservation Status

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.

Connecticut
historical (S-rank: SH), special concern, extirpated (code: SC*)
Massachusetts
extremely rare to rare (S-rank: S1S2), #NAME? (code: #NAME?)
Rhode Island
historical (S-rank: SH), state historical (code: SH)
Vermont
rare (S-rank: S2)

var. macrophylla

Connecticut
historical (S-rank: SH)

var. orbiculata

Massachusetts
unranked (S-rank: SNR)

Native to North America?

Yes

Sometimes Confused With

Platanthera macrophylla:
spur mostly 28-46 mm long (vs. P. orbiculata, with a spur mostly 10-26 mm long).

Synonyms

  • Habenaria orbiculata (Pursh) Torr.
  • Lysias orbiculata (Pursh) Rydb.

Family

Orchidaceae

Genus

Platanthera

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Information from Dichotomous Key of Flora Novae Angliae

15.  Platanthera orbiculata (Pursh) Lindl. N

round-leaved bog-orchid. Habenaria orbiculata (Pursh) Torr.; Lysias orbiculata (Pursh) Rydb. 
• CT, MA, ME, NH, RI, VT. Mesic to wet-mesic forests.