Turkey Tail

Trametes versicolor the Turkey Tail fungus has formed a complete circle over the decaying stump of an old crabapple tree that we took down several years ago.

http://www.fcps.edu/islandcreekes/ecology/turkey_tail.htm

You can use these in decorations if you carefully remove them from a tree stump or decaying log as you can see from the photo below.  If they touch water they will become dark and as they dry revert to their natural color  so that might mean you can use them to detect when your arrangement needs water. 

Good for wreaths also if they are big enough.