At first glance, I thought this was a kind of mushroom. But I have never seen green mushrooms. I thought again and realized this must be a whisk fern. It is very rare to see them in my area. I was very excited about my first discovery.
Whisk ferns like a warmer area. You will, therefore, have more chances to see them in the southern Japan and of course in
Taiwan, Hong Kong and Indonesia.
My dictionary says they are on a cliff or a tree. I don't know why they don't grow on the ground. Is it too cold in winter or too damp? The fern I found grows in the place where leaves and broken twigs lay thick on the cherry tree. It would take a few years to become this size.