Mushroom Gills

Its raining!  We have been so dry all summer.  The river behind my house has almost stopped flowing.  And the mushrooms have not popped up...until now.  They are starting to make a comeback.  This is probably a Velvet-footed Pax.  I like the gill structure.
Looks like I have managed to mix up my dates, so this becomes a back-blip.  How do I manage to do that?