Can anyone tell me what this is?

Update: I posted this on a homeschooling forum and someone knew what this is! She told me that these are called galls. The oak tree makes these in response to an insect chewing on the leaves. Here is a link that was provided. What an amazing God we serve! A whole new world of nature has opened up to us. Now my kids want to run outside and find some more galls.


We have been having a bit of a conundrum lately around here. We have found these on oak trees around here:

My son first found them on a tree that had fallen over in high wind. He picked them off of the tree and they were soft like a flower. Now a month or so later, they have turned hard and you can find them on the ground. You can find some, like these two, which are attached to an oak leaf.

They pink to reddish centers that gradually go out to a cream on the tips of the spikes. The larger ones are about 1/2 inch from tip to tip.

It is so wonderful to discover new things about the Lord's creation. But, every once in a while, we are stumped despite our books and the internet! If anyone knows what they are we would appreciate knowing!