Not Plain

But Plane. 
We have walked passed this felled tree by the river in the park many times, and I have felt drawn to taking some of the branches home to cut into logs for the fire. It has laid there for months, but I only noticed the seed balls recently. 

Google Lens suggests they are from a London Plane tree, and I agree.  The tree was not very old as the bark wasn't as distinctive as older trees can be. I am still thinking about taking a few branches.