Bolete Mushroom Blue Oxidation

This is a species of bolete mushroom that has been torn in half to reveal the tubes that make up the sponge-like pore surface and the interior flesh turning blue upon exposure to oxygen. 

This specimen was found on the Blue Square Trail at the Long Ridge Conservation Area, Sullivan, Missouri. This image is part of the article Trailheads: Portals to the Fungal Dimension.