pink lady’s slipper

(Cypripedium acaule)

Conservation Status


pink lady’s slipper

Photo by Bill Reynolds
  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FACW - Facultative wetland


FACW - Facultative wetland

  Northcentral & Northeast

FACW - Facultative wetland


Pink lady’s slipper is a 5½ to 19¾ tall, erect, perennial forb. It rises on a pair of basal leaves and a single leafless flower stalk (scape) from a long rhizome and widely-spaced roots. The rhizome is horizontal, slender, fleshy, and sometimes branched. The roots are white, fleshy or cord-like, and up to 13¾ long.

In the first two or three years after germination the plant lives entirely underground as a shapeless mass of cells (protocorm). In the third or fourth spring a single pair of ascending to spreading leaves rise directly from the rhizome. Each blade is elliptic, 3½ to 9 long, 1 to 4 wide. It sheaths the flowering stem at the base, is broadly angled at the tip, and is plaited or folded, like a fan. The upper surface is green. The lower surface is silvery and shiny. Both surfaces are covered with short glandular hairs. The margins are untoothed.

The inflorescence is a solitary flower at the end of an erect stalk (scape). The scape is hairy, leafless, and round in cross section. A single leaf-like appendage (bract) subtends the flower. The bract is stalkless, lance-shaped, green, hairy, to 1¾ long, and to ½ wide.

The flower has three sepals and three petals. The sepals are covered with glandular hairs. The upper sepal is elliptic to lance-shaped elliptic, yellowish-green to brown or purple, 1 to 1½ long, and 3 16 to wide. It is arched over the inflated lower lip petal. The bract subtending the flower arches over the upper sepal like a hood. The two lateral sepals are fused together into a single structure (synsepal) that is located directly below the lip petal. The synsepal is egg-shaped to lance-shaped, to 2 long, ¼ to 1 wide, and is similar in appearance to the upper sepal.

The two lateral petals are linear lance-shaped to lance-linear, 1 to 1¾ long, to wide, and similar in appearance to the sepals. They are bent abruptly downward to somewhat spreading and are slightly spirally twisted. The lower petal (lip) is inflated to form a large, showy, slipper-like, 15 16 to 2 long, 13 16 to 19 16 wide pouch. It is pink to magenta or purple, with dark branching veins. It is covered with glandular hairs. The upper (dorsal) surface has a deep longitudinal fissure the length of the lip.

Unlike other orchids, the filaments and style are not fused into a column. There are 2 stamens and an enlarged, modified, sterile stamen (staminode). The staminode is purplish-green and inversely egg-shaped to almost four-angled. It curves over the base of the lip petal and below the upper sepal. There is one style with a lobed stigma.

The fruit is a single, erect, ellipse-shaped, ribbed, ¾ to 19 16 long capsule. The persistent bract partially encloses the base of the capsule.




5½ to 19¾


Flower Color


Pink with red veins


Similar Species


Dry to wet. Woods, swamps. Acidic soil.




May 24 to July 10


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 24, 25, 28, 29, 30.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Liliopsida (monocots)  


Asparagales (agaves, orchids, irises, and allies)  


Orchidaceae (orchids)  
  Subfamily Cypripedioideae (slipper orchids)  


Cypripedium (hardy slipper orchids)  
  Subgenus Cypripedium  
  Section Acaulia  



Fissipes acaulis


Common Names


lady’s-slipper orchid

moccasin flower

pink lady’s slipper

pink lady’s-slipper

pink lady’s-slipper orchid

pink ladyslipper

pink moccasin flower

pink moccasin-flower

small pink lady’s-slipper

stemless lady’s slipper

stemless lady’s-slipper













Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.



The united filaments and style of an orchid. The structure formed by the united filaments of plants in the Mallow family.



A tuber-like mass of cells on the seed of an orchid that precedes the production of above-ground parts.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



An erect, leafless stalk growing from the rootstock and supporting a flower or a flower cluster.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.



A modified stamen that produces no pollen. It often has no anther.



A floral structure formed by the partial or complete fusion of two or more sepals.

Visitor Photos

Share your photo of this plant.

  This button not working for you?
Simply email us at
Attach one or more photos and, if you like, a caption.

Tim Blumentritt


I came across the link lady slipper for the first time in my life!

    pink lady’s slipper      

Bill Reynolds

    pink lady’s slipper      
    pink lady’s slipper      



  Cypripedium acaule
Zi W
  Cypripedium acaule  
  Pink Lady's Slipper
Andree Reno Sanborn
  Pink Lady's Slipper  

Cypripedium acaule
New Hampshire's State Wildflower

  Cypripedium acaule (Pink Ladyslipper)
Allen Chartier
  Cypripedium acaule (Pink Ladyslipper)  
  Cypripedium acaule
Joshua Mayer
  Cypripedium acaule  

Pink Lady Slipper

  eaTalk - Pink Lady Slipper Orchid

Uploaded on May 13, 2011

One of the first signs of spring in the region's coastal woodlands is the emergence of the Pink Lady's Slipper Orchid from beneath the blanket of pine needles that cover the maritime forest floor.

  Pink Lady Slippers

Uploaded on Jul 30, 2011

Pink Lady Slippers growing wild and free.




Visitor Videos

Share your video of this plant.

  This button not working for you?
Simply email us at
Attach a video, a YouTube link, or a cloud storage link.


Other Videos
  MyNature Apps; Identifying Pink Lady's Slipper, Cypripedium acaule

Uploaded on May 31, 2011

How to identify Pink Lady's Slipper, Cypripedium acaule also known as Stemless Lady's-slipper, or Moccasin Flower.

  Cypripedium acaule - Laddy Slipper Orchid

Uploaded on May 31, 2010

No description available.

  Dance Of The Lady Slippers.m4v
Douglas Foulke

Published on Jun 5, 2012

A time lapse look at Lady Slipper Orchids, (Cypripedium acaule), growing in Brookfield, CT.




Visitor Sightings

Report a sighting of this plant.

  This button not working for you?
Simply email us at
Be sure to include a location.
  Tim Blumentritt

Location: Wisconsin

I came across the link lady slipper for the first time in my life!

pink lady's slipper

  Bill Reynolds

Location: St. Louis Co.

pink lady's slipper





Last Updated:

About Us | Privacy Policy | Contact Us | © All rights reserved.