Cypripedium candidum
Muhlenberg ex Willdenow
Small White Lady's-slipper

Location Ontario, Manitoba, Saskatchewan.
Specific Habitat

Marly soil of fens. Shade intolerant. Decreasing due to invasion of their open habitat by woody shrubs. In southern Ontario, now only located on the delta islands of Lake St. Clair in open wet prairies, and at Stoco Fen in Hastings County, located in marshy openings.
Now extinct from near Bothwell in Kent County (Saunders, 1926), near Crystal Beach in Welland County (J. A. Simon and G. J. Yaki, pers. Comm,), near Port Elgin in Bruce County (CAN) and at Turkey Point in Norfolk County (Brownell, 1984a).

Flowering SeasonLate May to early June
Description

Height to 25cm.
Leaves 3 -4, elliptic to lanceolate.
Dorsal sepal and lateral petals greenish, often red-striped, lanceolate. Petals slightly longer and twisted. Lip white with violet veins within but no colour on the exterior, sometimes purple-spotted about the orifice. Yellow staminode with purple spots.

Comments

Undoubtably the rarest of the lady’s-slippers in Ontario. It has declined throughout most of its range, becoming rare as a result of drainage of wetlands and conversion of prairies to agricultural land.
It has been found that annual mowing effectively increased a population of Cypripedium candidum (Curtis, 1946), illustrating how simple management can help maintain a rare species.

References

Orchids of Ontario
The Canadian Field-Naturalist, Vol III - 1
The Orchids of Bruce & Grey

HabitatPlantFlower

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