Brain Fungus

A brain fungus, probably Myxarium nucleatum (= Exidia nucleata), but possibly Exidia thuretiana, growing on a dead log.  M. nucleatum is supposed to be distinguished from E. thuretiana by having white nuclei within it, and I think I can see these in the above photo.  However, there seems to be a lot of variation in the form and texture of these species (presumably with age and degree of hydration), so I am not completely confident in this identification.

Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2009-12-12.