This horrific-looking fungus may give you a fright if you chance upon it while foraging or hiking on your day off. But don’t worry, the dead man’s finger isn’t a zombie or corpse trying to get itself out of the ground—it’s just a really weirdly shaped freak of nature!
The dead man’s fingers (Xylaria polymorpha) fungus is a saprotrophic sac fungus that is often found on dead trunks and other decomposing organic materials in North American and European forests. It feeds on the carbohydrates in dead plant materials which frees the nutrients in them that serves as a natural fertilizer for other plants.
Believe it or not, dead man’s fingers fulfill an essential role in our environment. Their absence may even bring about the death of other plants that would have otherwise benefited from their existence! Wondering how? Scroll on to find out!
As gruesome as its common name may make it seem, the dead man’s fingers fungus isn’t actually all that scary.
In fact, this fascinating fungus doesn’t even always take the shape of a corpse’s finger reaching out to the sky from underneath the ground.
From its scientific name, “polymorpha” literally means many forms—finger-like protrusion is only one of them!
Another more common appearance of this fungus is a club-shaped fruitbody that somewhat looks like wood that’s been slightly burned due to its dark color.
It may also be bluish, with white or brown spores at the tip—resembling nails on fingers, making some of its 1–3 inch (3–8 cm) long protrusions that are in groups of five look all the more like someone’s hand or feet.
The dead man’s fingers fungus is an Ascomycetes. In other words, it is a sac fungus which as the name implies means that each of its compound fruiting bodies have such structures.
More often than not, you will see dead man’s fingers growing atop decaying plant matter, such as old tree trunks that have toppled down to the forest floor.
Besides that, they may also be found on other substrates including, but not limited to, herbaceous petioles and stems as well as woody seed pods.
Either way, it breaks everything down until it can absorb all the carbohydrates it needs, leaving behind all other—now—readily available nutrients.
Dead man’s fingers won’t be feeding on those leftover nutrients. Instead, other plants in its vicinity will benefit from them.
Dead man’s fingers are common in forests around North America and Europe, in places like Wisconsin and Ireland.
Sightings of mature specimens are more common from spring to fall. However, their fruiting bodies can be seen all year round.
Though there’s a history of dead man’s fingers fungus being mixed with sugar after being dried and powdered to promote lactation in mothers after giving birth in Ayurvedic medicine, it is largely considered inedible.
Having said that, very few people in the West have taken the chance of taking a bite of this fungus. Thus, the actual effects of eating woody mature ones remain largely unknown.
Some say that very young specimens may be edible since they’re still quite tender and just taste like ordinary mushrooms.
As far as I know, there are no reports of poisoning in people who have eaten dead man’s fingers fungus at such an early stage in small amounts—even when they’re raw.
But it’s important to note that only a few sac fungi are considered edible. The two most common examples are morels and truffles.
Furthermore, scientists have found that dead man’s fingers contain amatoxin and phallotoxin both of which are compounds typically found in the most poisonous mushrooms on Earth.
Now, to be completely clear, despite the beneficial effects of dead man’s fingers in forests where plants are given a helping hand from the decomposition of organic material, you don’t want to find these in your own backyard!
You see, its presence is often closely tied to the decomposition of wood and/or black root rot. As you could imagine, that can easily spell disaster for the garden you’re worked hard on!
Commonly affected shrubs and trees include:
- American elm
- Norway maple
If you suspect that there are dead man’s fingers in your yard, carefully remove and discard all of the infected plant materials—get rid of as much of the roots as you can find.
Contact your local extension office to know if there are any registered fungicides for proper treatment available in your area.
- “Dead Man’s Fingers” by Ann Joy and Brian Hudelson in the University of Wisconsin-Madison Division of Extension
- “Spooktacular Flora and Fungi” by Mandy L. Smith and Joan Jubela in PennState Extension