Spiranthes incurva (Jenn.) M.C. Pace

Sphinx Ladies' Tresses

Habit: Spiranthes incurva. ~ By Matthew C. Pace. ~ Copyright © 2024. ~

Flowers: Spiranthes incurva. ~ By John Gange. ~ Copyright © 2024. ~

Inflorescences: Spiranthes incurva. ~ By John Gange. ~ Copyright © 2024. ~

Fruits: Spiranthes incurva. ~ By John Gange. ~ Copyright © 2024. ~

Plant form: Spiranthes incurva. ~ By John Gange. ~ Copyright © 2024. ~

Facts About

Accepted Synonym: Ibidium incurvum

Spiranthes incurva, the Sphinx Ladies' Tresses, is a recently described species formerly within the S. cernua complex. It produces 1-5 basal leaves which are held upright but usually wither before the plant flowers. The white to pale ivory flowers form a tightly coiled spiral along the spike in the autumn with lateral sepals that sweep upwards. The raised nectar glands at the base of the smooth labellum curve inwards and are a key feature to distinguish this orchid from S. magnicamporum. This orchid grows in a variety of open habitats, such as fens, meadows, and lake edges, as well as along roadsides.

The conservation status of Spiranthes incurva has not been widely reported and may currently be under review in several areas where it occurs.

Pollination

Although specific pollinators for this orchid have not been identified, most Spiranthes attract bumble bees that move upward on the inflorescence in search of nectar. Older flowers at the base of the stalk have more nectar, which makes them an efficient first stop for the foraging bumble bees.

Ecosystem Type

Bogs, dunes, fens, grassland, meadows, prairie, stream bank

Characteristics

Habitat:: terrestrial

Leaf arrangement:: basal

Number of leaves on stem:: absent

Form of the labellum:: the labellum is not pouch-like

Labellum outline:: the labellum is simple

Main color of labellum:: white

Nectar spur:: absent

Inflorescence type:: the inflorescence is a spike

Labellum characteristics:: the labellum is simple

Labellum length:: 7.4–9.9 mm

Sepal length:: 8.6–10.9 mm

Plant height:: Up to 40 cm

Show All Characteristics

Flowers
Floral bract length:

9.5–9.7 mm

Flower petal color:

white

Flower symmetry:

the flower is zygomorphic
Flowering date:
August

September
Form of the labellum:

the labellum is not pouch-like

Inflorescence type:

the inflorescence is a spike

Labellum characteristics:

the labellum is simple

Labellum length:

7.4–9.9 mm

Labellum outline:

the labellum is simple

Labellum position:

the flowers are resupinate

Main color of labellum:

white

Nectar spur:

absent

Number of stamens:

1

Pollen sacs:

the pollinia remain intact and do not fragment into smaller parts

Self-pollinating flowers:

there are no cleistogamous flowers

Sepal length:

8.6–10.9 mm

Sepals fused only to sepals:

the sepals are separate from one another

Shape of viscidium:

linear

Spots on labellum:

no
Fruits or seeds

Seed capsule orientation:

the capsule points upwards or outwards
Growth form

Plant height:

Up to 40 cm

Roots:

the rhizomes are non-coralloid

Underground organs:

slender roots

myco-heterotrophic or not:

the plant is chlorophyllous
Leaves
Leaf arrangement:

basal

Leaf blade edges:

the leaf edges are entire
Leaf blade shape:
lanceolate

linear
Leaf blade tip:

the tip of the leaf blade is acuminate

Leaves during flowering:

leaves are absent during flowering

Number of bracts on stem:

Up to 2

Number of leaves on stem:

absent
Place
Ecosystem type:
bogs

dunes

fens

grasslands

meadows

prairie

stream banks
Habitat:

terrestrial
Location:
Illinois

Indiana

Iowa

Kansas

Maine

Michigan

Minnesota

Missouri

Nebraska

New Brunswick

New Hampshire

New York

Ohio

Ontario

Pennsylvania

Quebec

Vermont

Wisconsin
Facts and Uses

Mycorrhiza

Monitoring

Propagation

Restoration

Native to North America

Yes

North American Conservation Status & Distribution

Conservation Status

Select a location to view conservation status:

	Conservation and Wetland Status
Global Rank	N/A
US Status	N/A
Canadian Status	N/A

	Conservation status for: Iowa
Global Rank	N/A
US Status	N/A
Iowa Rank	N/A
Iowa Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Illinois
Global Rank	N/A
US Status	N/A
Illinois Rank	N/A
Illinois Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Indiana
Global Rank	N/A
US Status	N/A
Indiana Rank	N/A
Indiana Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Kansas
Global Rank	N/A
US Status	N/A
Kansas Rank	N/A
Kansas Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Michigan
Global Rank	N/A
US Status	N/A
Michigan Rank	N/A
Michigan Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Minnesota
Global Rank	N/A
US Status	N/A
Minnesota Rank	N/A
Minnesota Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Missouri
Global Rank	N/A
US Status	N/A
Missouri Rank	N/A
Missouri Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: New Brunswick
Global Rank	N/A
US Status	N/A
New Brunswick Rank	State Rare
New Brunswick Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Nebraska
Global Rank	N/A
US Status	N/A
Nebraska Rank	N/A
Nebraska Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: New York
Global Rank	N/A
US Status	N/A
New York Rank	N/A
New York Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Ohio
Global Rank	N/A
US Status	N/A
Ohio Rank	N/A
Ohio Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Ontario
Global Rank	N/A
US Status	N/A
Ontario Rank	Secure
Ontario Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Pennsylvania
Global Rank	N/A
US Status	N/A
Pennsylvania Rank	N/A
Pennsylvania Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Quebec
Global Rank	N/A
US Status	N/A
Quebec Rank	N/A
Quebec Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Vermont
Global Rank	N/A
US Status	N/A
Vermont Rank	N/A
Vermont Status	N/A
Canadian Status	N/A
Wetland Status	N/A

	Conservation status for: Wisconsin
Global Rank	N/A
US Status	N/A
Wisconsin Rank	N/A
Wisconsin Status	N/A
Canadian Status	N/A
Wetland Status	N/A

North America Distribution

Adapted from USDA data

Facts About

Pollination

Ecosystem Type

Characteristics

Flowers

Fruits or seeds

Growth form

Leaves

Place

Facts and Uses

Native to North America

North American Conservation Status & Distribution

Conservation Status

North America Distribution