Cypripedium calceolus : Yellow Ladys Slipper


Scientific Name:

Kingdom: Plantae


Class: Monocoteldonae (one seed-leaf)

Family: Orchidaceae (Orchid Family)

Genera: Cypripedium (Lady's Slipper) (Gk. Kypris=Venus, godess of love + podion=a slipper, referring to the shape of the flower)

Species: calceolus (Latin for small shoe)

Synonym(s): C. parviflorum

English Name(s):

Yellow Ladys Slipper, Noah's Ark, Moccasin Flower, Venus' Shoe

First Nation Names:



  • Stems 15-30cm tall, with 3-5 leaves.


Reproductive Parts:

  • Flowers perfect (bisexual). Zygomorphic (biliteral symmetry).
  • Petals 3 of which the side two are alike but are different from the lower one which is lip like.
  • Sepals 3.
  • Column (fused filaments and style) with 2 anthers (male parts).
  • Lateral petals long, linear. Lower petal (lip) inflated, sac or slipper like.
  • 1 to 3 fragrant flowers.
  • Lateral petals 3.5-5cm long. same colour as sepals. Longer than Lower petal (lip). Spirally twisted.
  • Lower petal (lip), 2-3.5cm long, yellow, often purple spotted on inner surface.
  • Sepals madder purple, lateral sepals united.


  • Fruit a three chambered capsule containing innumerable minute seeds.
  • Capsules erect, glandular to hairy.
  • Each capsule produces 15,300 - 15,700 seeds.

Not to Be Confused With:

  • No other flower in our area is both the same shape and colour as Cypripedium calceolus (Yellow Lady's Slipper).



  • Herbacious.
  • The flowers have only 2 anthers (male parts) which is concidered a primitive charactaristic in the Orchid Family.

Life Cycle:

  • Perennial.
  • Blooming occurs after 2-3 years of growth.

Seasonal Cycle:


Animal Uses:

  • Pollinated by syrphid flies.
  • The 'Slipper' is an insect trap. It is easy for insects to enter the slipper but the smooth surface makes it hard to escape. There is a strip of hairs at the 'heel' of the slipper which an insect can climb up and out of the flower.
  • When escaping the flower, the insect has to come incontact with first the pistle (female part), where it can deposit any pollin from other flowers, and then the anthers (male part), where it can pick up new pollen to take to another flower.


  • Likes calcareous soils.
  • Open moist woodlands.




  • This is the most easily grown Cypripedium and is a popular garden Orchid.
  • Propogation is done by division. Each year 3-8 shoots are produced and 1-3 of these can be removed in the spring. Divisions should have roots and be planted in coniferous humus and woodchips.


  • Sometimes made into a sweetened root tea. used as a sedative and pain killer.
  • Roots are used in an extract form as a sedative, especially for nerviousness, hystaria, and anxiety.


    Traditional Gwich'in:





            Traditional Other:




                • Roots dries and ground were used as a sleeping potion.
                • The Cherokee mixed the roots with Cerastium and used for worms or with Taraxacum for kidney ailments.
                • The roots were reported to be superior to opium for inducing sleep and they are not narcotic.
                • Cypripedin a powder produced by precipitating the tincture with water was said to have greater powers than the root and was given to children instead of opium.
                • Plants in this genus were known for the drug Cypripedium which was used as a gentle nervous stimulant or antispasmodic.
                • Plants taken in a sweetened concoction for headache.
                • Roots were chewed as a sedative especially during menstruation and childbirth.



                  Full bloom

                  Range Maps

                  World Range: Circumpolar with gaps. Rare throughout its range. In N.A. from NL to BC and YT south to AZ, LA,and V

                  Prov/State Abrev. List

                  In Yukon: Rare, Known from three locations in central Yukon and one near Faro.

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