Cerrena unicolor (Bull.) Murrill 1903
The cap is often dressed in green algae. The underside is a pore maze which may become tooth-like in time. It is an annual that fruits on dead hardwood. It is a white rot fungus. The wood on which it grows is visited by the female horntail. She drills a hole in the wood and deposits her eggs in it along with spores from the fungus. The mycelium that ensues provides food for the growing larvae. Insuring that horntail populations stay within limits, Cerrena unicolor also emits a pheromone that attracts the ichneumon wasp to find and parasitize the horntail larvae. A complicated relationship! It is in the Cerrenaceae family of the Polyporales order.
Cerrena unicolor
Cerrena unicolor