A Sunny Day in the Forest

Lichen

I believe this variety of lichen is called Hooded Bone, named for its hood-shaped lobe tips.

"Many species [of lichen] are sensitive to air pollution to differing degrees and have been employed successfully to monitor levels of air pollution, especially sulphur dioxide." source: Plants of Northern British Columbia, MacKinnon, Pojar, Coupe, published by Lone Pine Publishing