The underside feels like the skin of a human's foot or the palm of my hand.
Even the curled edges mimic the curling bark. In the photo below you may see the two mushrooms hidden by surrounding sycamore bark curls. I can't help but believe that this is no coincidence. Could it be that the fungi rely the sycamore roots and use it's bark as camouflage?
The surface of the mushroom makes a bowel that would hold much water were it not for a drain built into its edge.
What great design.