Found in swampy or boggy woods and in openings of cedar swamps. Occasionally it can be seen in wet, open roadside ditches. Prefers some sun and "cold bottom" conditions.

Height: 20 - 90 cm.
Leaves: 3 - 6, ovate-lanceolate, strongly ribbed and folded, spirally sheathing the stem, pubescent.
Flowers: 1 or 2, occasionally 3 or 4; sepals and petals white, lip an inflated pouch, 2-5 cm. In length, white but covered with rose-purple markings, sometimes described as rose streaked with white.

Cypripedium reginae, like the yellow lady's-slippers, is covered by a dense mat of fine pubescence which can be irritating to the skin of some people in the manner of poison ivy.

Cypripedium reginae forma albolabium Fernald and Schubert
White Lady's-slipper

The white form occurs rarely throughout the range of the species and is frequently found growing among the pink and white slippers.
Vegetatively, it is identical to the pink and white form but the lip is completely lacking in pigment. It is sometimes an off-white or ivory.
The pure white form has been reported in only three locations in Ontario: the Luther Marsh, the Minesing Swamp, and on the Bruce Peninsula. Across Canada, it can be found from Saskatchewan to Newfoundland.

The Genus Cypripedium
The Canadian Field-Naturalist Vol III-1
The Native Orchids of the United States and Canada excluding Florida
The Orchids of Bruce & Grey