Phaeocalicium polyporaeum

Phaeocalicium polyporaeum, the fairy pin or common pin, is a species of non-lichenized fungus in the genus Phaeocalicium. They grow to a maximum size of 2.5 mm and resemble black matchsticks, with thin stalks and wider caps, in groups or rows primarily on the caps of Trichaptum biforme. Fairy pins are a type of parasitic fungi that grow primarily on the caps of Trichaptum biforme, but have also been reported on Trametes versicolor. They often co-occur on the upper side of caps with green algae on host fungi.

Fairy pins can be distinguished from other species of Phaeocalicium by their spores, which are very pale brown.