One of my favorite little mushrooms, they can literally cover a log from top to bottom in some cases. They’re not poisonous, but they aren’t very edible either, due to being so small and bitter. However, I have heard of some people who consume them regularly. I imagine if you cook them a bit the bitterness will be less noticeable.
Xeromphalina campanella only grows on dead coniferous wood, like Pine trees. If you find a mushroom that looks exactly like these, but growing on a dead hardwood like Oak, than you found Xeromphalina kaufmanii.
The genus name Xeromphalina means “little dry navel” and campanella means “bell-shaped”.
Here are my photos of Xeromphalina campanella: