They look really cute and woodlandy on a tree especially with a little squirrel nearby. They remind me of the art and Christmas books by Jan Brett. (You should really check out her webpage for a lot of great craft ideas!)
I found this mushroom pattern on ravelry, and if you're not a member you should become one! The pattern is by Kathryn Ivy and is available free on her website here. I followed the patterns as directed and I used Cascade and Lion's brand yarn because both of those felt really well. The Lion's brand is cheap at Beverly's. Here is a picture of my finished specimens:
The Amanita mushroom turned out well. I needle felted the spots on, impaling my fingers several times in the process. Despite that I decided to make more for gifts.