@Ceili,
												Ceili wrote:
It's a button mushroom, I'm not sure what the green stuff is, as fungi is never green.
 
     Not mushroom Ceili. It is much bigger and heavier than any mushroom. I bought one from market this morning, which weighed one kilogram.  
   I believe it is one of the varieties of radish, but it tastes better.
     Like white radish: