Very nice macro Paul! It's difficult to determine since it has lost it's color to age. Judging by the distance between gills, looks to me like either a Fiberhead or Milky, though a Russula is a good guess also. I can also see a little fruitfly enjoying himself.
You've started already with the mushrooms I see. It's a really "dark" mushroom. Nice contrast on these brown leaves. Put on your rainboots and shoot some more.... I like autumn scenes.
Gr. Eric