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• Orchidaceae
• Cypripedium
• Cypripedium acaule

Cypripedium acaule — pink lady's-slipper

Facts

Pink lady's-slipper is typically found on acidic soils. It is pollinated by bumblebees that enter the flower through a slit in the labellum, pass under the stigma that removes any pollinium (pollen sac) that may be present on the bee, and then under one of two anthers that attach a pollinium onto the bee. Finally, the bee exits through a small opening in the back of the flower. Contact with the floral bract is known to cause skin irritation in some people; other parts of the plant may also have this effect.

Habitat

Anthropogenic (man-made or disturbed habitats), bogs, forest edges, forests, swamps, woodlands

Characteristics

• Flowers

  Flower petal color

  • brown
  • green
  • red
  • yellow

  Flower symmetry

  there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)

  Flowering date

  • July
  • June
  • May

  Flowers per inflorescence

  At least 1

  Form of lower petal

  the labellum has a pouch-like shape

  Hairs on inflorescence axis

  NA

  Inflorescence type

  the inflorescence has only one flower or a pair of flowers on it

  Labellum position

  the labellum is in the lower position on the flower

  Length of flower stalk

  0 mm

  Length of narrowed base of lower petal

  0 mm

  Length of peduncle

  150–610 mm

  Lobes at base of lower petal

  0 mm

  Lower petal characteristics

  the labellum is in the shape of a pouch

  Lower petal length

  30–67 mm

  Lower petal outline

  the labellum is simple in form

  Lower petal strongly red-veined

  • no
  • yes

  Main color of lower petal

  • pink to red
  • white

  Nectar spur

  there are no nectar spurs on the flower

  Nectar spur length

  0 mm

  Number of stamens

  2

  Orientation of side petals

  the lateral petals slant somewhat downward

  Pollen sacs

  NA

  Self-pollinating flowers

  there are no cleistogamous flowers on this plant

  Sepal length

  19–52 mm

  Sepals fused only to sepals

  the sepals are fused to each other (not other flower parts), at least near their bases

  Shape of viscidium

  NA

  Spots on lower petal

  no

  Spur opening membrane

  NA

  Spur opening shape

  NA

• Fruits or seeds

  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

  • there are only slender roots on the plant
  • this plant has a rhizome (a horizontal underground stem with roots growing from it)

• Leaves

  Bract relative length

  the bract is longer than the associated flower

  Features of leaves

  • the leaf does not have any of the mentioned special features
  • the leaf is pleated or folded back and forth along its length

  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

  90–300 mm

  Leaf blade length to width ratio

  2–3.6

  Leaf blade shape

  • the leaf blade is elliptic (widest near the middle and tapering at both ends)
  • the leaf blade is oblong (rectangular but with rounded ends)
  • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
  • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)

  Leaf blade tip

  the tip of the leaf blade is obtuse (bluntly pointed)

  Leaf blade width

  25–150 mm

  Leaves during flowering

  there are leaves on the plant when it is flowering

  Number of bracts on stem

  0

  Number of leaves on stem

  absent

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • bogs
  • edges of forests
  • forests
  • man-made or disturbed habitats
  • swamps
  • woodlands

Wetland status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae