Xylaria polymorpha

Common Name: None.
Description: Fruit body 2-8 cm high, 1-3 cm wide, irregularly club-shaped passing into a short cylindrical stalk below; black with a finely wrinkled or roughened surface.
Habitat: in groups or clusters on rotting wood and stumps, often beech and maple. Sometimes abundant. Found throughout North America.
Edible: Not edible.

Source: Mushrooms of North America by Roger Phillips.