Hiking in the Columbia Gorge in the area of Horsetail Falls we found the Western Fairy Slipper (Calypso bulbosa var. occidentalis) growing in various locations along the trail. Interestingly, in the steeper areas it seemed always to be on the northwest corner of the outcrops. We saw it so often in that location that we began to look for it there and found it in places we had previously missed.
In those locations they were often half hidden under other vegetation (and thus known as the "Hider of the North"), but the other location where we found them was different. That location was in an open mixed woodland, quite level where the plants got only a very little bit of sun and where there was almost no other vegetation. It was in that location that we began to find Listera cordata as well though we we tended to find more of it in damper, shadier locations.