It is creamy white underneath and the top part seems to be blending into the tree bark, almost as if it mimicking it.
This is the feature I thought was most interesting too. It has the exact same bark splitting shapes and colors.
On really old hollowed out trees, when the inside becomes wet and the bark rots away, I have found some of the most amazing black compost buried inside trees. All kinds of fungi, moss, bacteria, and micro organisms turning the compost into something alive and healthy.
Sometimes these damp spots where mushrooms grow can kill the tree over time, mainly because the water isn't draining. I'm attempting to learn how moss is beneficial or damaging to tree growth on some species. Anywhere damp and shady it seems to grow best.
Yes, fungi is normally an indicator that the tree is rotting or dying as fungi are there to help break down dead wood. However, I think this one just seems to live in a symbiotic relationship with the tree. It is still producing acorns and the leaves are looking healthy too.
Thank you for stopping by and taking an interest in my post, much appreciated.