Small white lady's slipper (Cypripedium candidum)

Perennial. Stems up to 1 foot tall, often clumped. With 3 or 4 slightly folded, ascending leaves. Single flower with white inflated pouch, 2 long curly brownish petals at sides, 1 narrow sepal above and 2 fused sepals below pouch. Rare in calcareous groundwater seeps, wet prairies. Blooms early June. A state special concern plant in Minnesota.