This delicately colored lady-slipper is the hybrid of white and small-yellow. It is this shade when it opens, and soon fades to white. This plant also occurs at the edge of Saturday's swamp. But I've never seen any white lady-slippers there. There is much confusion about yellow lady-slippers, and even more with their hybrids. I once even heard that Dr. Farwell's near-at-hand good stuff even came into the matter. Three varieties are recognized. Different authors apply those names to different plants. What we called var. makasin here is often called var. parviflorum. I guess you can only resolve it by deciding who to trust. In this case Dr. Anton Reznicek et al at the University of Michigan (another of course!). Or by looking at the original specimens, which might involve a trip to London.