Goodyera oblongifolia    "Giant rattlesnake plantain"   

(photo coming soon I hope, haven't yet found them in Yellowstone, but they are prolific near Bozeman)

This orchid has a rosette of shiny evergreen leaves with a light stripe down the rib of the leaves. It sometimes seems to carpet the floor of the forest under evergreens. They spread with laterals off the rhizome. According to Case (1987) Goodyera species also hybridize with each other. 

Locations: (coming soon I hope)

Blooming: mid-to-late August into September. 

Sniff test: N/A