Cypripedium acaule
Pink Lady's-slipper, Stemless Lady's-slipper

Location Newfoundland, Nova Scotia, Prince Edward Island, New Brunswick, Quebec, Ontario, Manitoba, Saskatchewan, Alberta, Northwest Territories.
Specific Habitat

Found in a variety of shaded, acidic habitats, both wet and dry, in boreal and temperate regions. For example, in the Bruce Peninsula area, it grows mostly in acid conifer-dominated swamps or wooded bogs. It can also be found growing in dry sandy or rocky places if the soil requirements are right, particularly under Jack Pines in the northern part of the Bruce Peninsula. Also located in White Pine stands along Lake Erie.

Flowering SeasonMid to end of May until early July.

Height 10 - 59cm. Short, underground stem from which two or, rarely, three dark green, strongly veined basal leaves rise, sheathing the scape.
Leaves and 12-40 cm scape are hairy. One lanceolate, green bract arches over solitary flower.
Flower: sepals and lateral petals yellow-green to purplish-brown with lateral petals spreading, somewhat twisted. Lip forming a pouch, showy pink (rarely white) with red or purplish veining. Lip opens to an elongate fissure on upper surface. Fragrance usually pleasantly floral, varying in intensity from quite strong to none, sometimes with sharp notes.


Requires very definite environmental conditions, rarely surviving transplanting to gardens. Root system extends approximately a meter in opposite directions from the plant, and cannot withstand severance in order to transplant.
Germination from seed to flowering plant requires 10-16 years. In the Great Lakes Region, late hard frosts will cut down most scapes, but affect the leaves themselves very little; consequently, few plants bloom in such a year. Following a frost-free blooming season, hundreds of seed pods ripen in the larger colonies.
Pollinated by bumble bee (Bombus) queens (Stoutamire, 1967, 1969).


Orchids of Ontario
Orchids of the Western Great Lakes Region
The Canadian Field-Naturalist Vol. III - 1
The Orchids of Bruce & Grey


© Royal Botanical Gardens, Dr. Donald Gunn Image Collection.