Pretty Flower Fungus in Oak Tree
I believe it is a type of fungus. 


Yes, this is a kind of fungus. Specifically, I believe it's of the genus Laetiporus sp., and is commonly known as "chicken of the woods" and "sulfur shelf". Notice that in both images the mushroom is growing on an oak tree.






  Is this edible?


I strongly recommend that you watch this and this video. Collectively, they provide more than enough information on how to properly ID the fungus, how to harvest &amp; cook, any potential look-alikes, and even possible medical applications.

IF my suggested identification of your posted organism is correct, then yes, it's edible.