Mycena haematopus

Mycena haematopus, commonly known as the bleeding fairy helmet, the burgundydrop bonnet, or the bleeding Mycena, is a species of fungus in the family Mycenaceae, of the order Agaricales. First described scientifically in 1799, it is classified in the section Lactipedes of the genus Mycena, along with other species that produce a milky or colored latex.

The fruit bodies of M. haematopus have caps that are up to 4 cm (1+5⁄8 in) wide, whitish gills, and a thin, fragile reddish-brown stem with thick coarse hairs at the base. They are characterized by their reddish color, the scalloped cap edges, and the dark red latex they "bleed" when cut or broken. Both the fruit bodies and the mycelia are weakly bioluminescent.

It is widespread and common in Europe and North America, and has also been collected in old Japan and Venezuela. It is saprotrophic—meaning that it obtains nutrients by consuming decomposing organic matter—and the fruit bodies appear in small groups or clusters on the decaying logs, trunks, and stumps of deciduous trees, particularly beech. The edibility of the species is not known definitively. It produces various unique alkaloid pigments.