This is the nivea (albino) form of the Western Fairy Slipper, Calypso bulbosa var. occidentalis fma. nivea. We found four of them in different places last spring.
We also found a near-albino with hints of pink color and of the brownish-purple color at the back of the pouch. It is sometimes difficult to tell these pale forms from flowers that are fading, since even the pink flowers turn white just before they wither, but the yellowish color at the back of the pouch and lack of spotting on the lip give this one away.
This is probably a pale form since the flowers still look fresh, but the photo shows the difference in the color of the pouch and lip when compared with the previous photo.
Here is a flower that is fading next to one that is still fresh. The difference in the color of the pouch and lip should be evident. Even the fresh flower, however is light-colored.
This is the ordinary form of the Western Fairy Slipper, but a very intensely colored flower in all its parts. We found this at Sehome Hill Arboretum.
We also saw for the first time in Washington the Eastern Fairy Slipper, in its rose-colored (lip) form, Calypso bulbosa var. americana fma. rosea. With its yellow beard it is obviously different from the Western Fairy Slipper.
And finally, here is a blog post about all these different forms:
Native Orchids of the Pacific Northwest and the Canadian Rockies: Varieties and Forms of Calypso bulbosa