I have been asked if yesterday’s white fungus had gills so I took a shot of the underside. No gills but tiny protrusions that look very much like the underside of a starfish.
It has a variety of names: Toothed Jelly Fungus, False Hedgehog Mushroom or White Jelly Mushroom (Tremellodon gelatinosus or Pseudohydnum gelatinosum).