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Bleeding Fairy Helmet - Mycena haematopus

Good evening, friends,

This week's mushroom is Mycena haematopus, commonly known as the bleeding fairy helmet - perhaps our best common name yet. This mushroom was found in the ramble on 10/8/2021 and, again, identified on iNaturalist by Ethan from the New York Mycological Society. The mushrooms were growing out of an Eastern redbud tree (Cercis canadensis).

Mycena haematopus

Fun Facts

As the common name suggests, this mushroom will exude a dark red liquid, known as a latex, from any part of the mushroom when wounded. I didn't get a great picture of this but you can see in the unfocused image below some liquid forming at the base of the stipe where I detached the mushroom from the wood. In Ancient Greek, "haemat" means blood and "pus", as we learned last week, means foot.

Another interesting note is that both the mushroom and mycelium of M. Haematopus is mildly bioluminescent. The thinking is that M. Haematopus, and other bioluminescent mushrooms, co-evolved with insects that are attracted to the light. The mushroom spores will then attach to the insect and the insect inadvertently acts as a vehicle for spore dispersal. This allows the spores to travel much farther than normal environmental factors would allow.

Underside of Mycena haematopus in Aubrey's hand


M. haematopus is saprobic on the deadwood of hardwoods. It grows spring through fall and is found in North America, Europe, and Asia. It can grow as a solitary mushroom but is typically found in small clusters like the specimens we have here. There is a similar species of bleeding mycena, Mycena sanguinolenta, that grows from detritus in conifer woods. M. haematopus has caps that range from 1-5 cm wide and, along with the substrate, the larger capsize of M. haematopus is a distinguishing factor between the two species.

An interesting caveat is that M. haematopus is regarded as a late colonizer species - a fungus that will grow on wood that has already been colonized and substantially degraded by other fungi. That's likely not the case with this wood, seeing as all of the bark is still intact and the tree is alive, which may suggest this isn't M. Haematopus after all. Mushrooms in the genus Mycena are tough to ID using physical features because they are all quite alike, and this just illustrates the importance of using DNA sequencing to confirm identification of these similar looking shrooms. DNA kits are becoming more accessible and I hope to soon have a setup where I can sequence my own finds. Until then we have the great community of the New York Mycological Society and iNaturalist to help us with identification.

Mycena haematopus in Aubrey's hand

The winter solstice is (mercifully) tomorrow,



1) Kuo, M. (2010, December). Mycena haematopus. Retrieved from the MushroomExpert.Com Web site:


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