Paxillus filamentosus

Paxillus adelphus (Paxillus filamentosus, Paxillus rubicundulus), commonly known as the alder roll-rim, is a basidiomycete fungus which is associated with alder (Alnus) in northern Europe and southwestern Greenland, and North America. It closely resembles Paxillus involutus, but its fruit bodies are generally smaller.