Xylaria polymorpha is a saprotrophic fungus, that grows on dead or dying wood. Typically found near rotting or injured tree stumps, the fungus decomposes the wood and breaks organic matter down where it can be absorbed as nutrients by surrounding plants. Each finger serves as a reproductive vessel for the fungus with a small hole at the top that releases reproductive spores.
https://en.wikipedia.org/wiki/Xylaria_polymorpha