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- Platanthera orbiculata
Platanthera orbiculata — round-leaved bog-orchid
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Facts
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
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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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
-
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)
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.
- Connecticut
- historical (S-rank: SH), special concern, extirpated (code: SC*)
- Massachusetts
- extremely rare to rare (S-rank: S1S2)
- Rhode Island
- historical (S-rank: SH), state historical (code: SH)
- Vermont
- rare (S-rank: S2)
var. macrophylla
- Connecticut
- historical (S-rank: SH)
From Flora Novae Angliae dichotomous key
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.
Native to North America?
Yes
Sometimes confused with
- Platanthera hookeri:
- scape with 0 very rarely 1 bract-like leaves, ovary sessile, flowers green to green-yellow, and labellum upcurved (vs. P. macrophylla, with the scape with 1–6 bract-like leaves, ovary on a stipe 5–10 mm long, flowers white to green-white, and labellum downward oriented).
- 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.