Large yellow lady-slippers are reasonably common in the north. But they are vulnerable to the full range of threats. Their habitats are dwindling, and invasives are crowding them. People are the larger part of that last category. The fen preserve the Botany Club is visiting Saturday could have been larger. While negotiations were happening for the extra parcel, someone went in with ORVs and destryed it. When they were done, nothing was left but mud. There were other protected plants too. Fortunately, across the road, things are in good shape. That eastern section is partly protected by a large roadside ditch. It was heavily infested with invasive buckthorn, but volunteers now have that under control.
The image here is of a color form that lacks the red-brown pigment in the sepals and lateral petal.