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Platanthera macrophylla — large-leaved bog-orchid

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Facts

Large-leaved bog-orchid is true to its name, with very large basal leaves resting more or less flat on the ground. A study of bog-orchids (Platanthera) showed that species with longer nectar spurs (which makes nectar available only to insects with longer mouth parts) also tend to have more restricted geographical distributions. Large-leaved bog-orchid has unusually large nectar spurs, is pollinated by large moths, and is restricted to northeastern North America.

Habitat

Forests, 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
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf arrangement
the leaves are growing only at the base of the plant (basal)
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
  • green to brown
  • 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 is simple in form
Lower petal length
10–23 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
    9–33
    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
    80–350 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
    Lobes at base of lower petal
    0 mm
    Lower petal characteristics
    the labellum is simple in form
    Lower petal length
    10–23 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
    Nectar spur
    the flower has at least one nectar spur on it
    Nectar spur length
    28–46 mm
    Number of stamens
    1
    Orientation of side petals
    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
    18–25 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
    the leaves are growing only at the base of the plant (basal)
    Leaf blade edges
    the edges of the leaf blade have no teeth
    Leaf blade length
    70–240 mm
    Leaf blade length to width ratio
    1.3–1.4
    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
    50–190 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)

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
rare (uncertain) (S-rank: S2?), #NAME? (code: #NAME?)
Rhode Island
historical (S-rank: SH), state historical (code: SH)
Vermont
rare (uncertain) (S-rank: S2?)

From Flora Novae Angliae dichotomous key

13.  Platanthera macrophylla (Goldie) Lindl. N

large-leaved bog-orchid. Habenaria macrophylla Goldie; H. orbiculata Pursh var. macrophylla (Goldie) Boivin; Platanthera orbiculata (Pursh) Lindl. var. macrophylla (Goldie) Luer • CT, MA, ME, NH, RI, VT. Mesic to wet-mesic forests.

Native to North America?

Yes

Sometimes confused with

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

Synonyms

  • Habenaria macrophylla Goldie
  • Habenaria orbiculata Pursh var. macrophylla (Goldie) Boivin
  • Platanthera orbiculata var. macrophylla (Goldie) Luer

Family

Orchidaceae

Genus

Platanthera