The Slipper Orchids
Cypripedium candidum: White lady's slipper
The White lady's slipper occurs in Ontario Canada and in the eastern and central United States from New York west to North Dakota and from Minnesota south to Missouri and Kentucky. It is a prominent species of the Midewin National Tallgrass Prairie in Illinois.
Cypripedium candidum grows in prairies where there is moisture but full sunlight. It can be found in limestone barrens and on forest edges. It even grows along railroad tracks.