Finland's only orchid species, "Cypripedium calceolus", grows in the Paljakka reserve. "Cypripedium calceolus" is frequently associated with stands of hazel trees. "Cypripedium calceolus" sensu stricto ("in the strict sense") does not occur in North America. "Cypripedium calceolus", with the Rev. Henry Harpur Crewe. "Cypripedium calceolus" is known to primarily associate with mycorrhizal fungi in the genus "Tulasnellaceae". Cypripedium calceolus is a lady's-slipper orchid, and the type species of the genus "Cypripedium".