Dyeball, Dog Turd, or Dead Man's Foot? - The Unfortunate Appearance of Pisolithus arenarius
- Aubrey
- Oct 20
- 5 min read
Good morning, friends,
This week’s mushroom comes to us from the sandy grasslands of Breivogel Ponds Conservation Area in Falmouth, MA. A sandy plain devoid of trees might not be an area where you’d expect to find tons of mushrooms, but the place was teeming with them after a nor’easter dropped over four inches of rain on us last week. The title of this article lists a few of the common names for these rather unsightly lumps, and Pisolithus arenarius doesn’t exactly roll off the tongue either, but don’t let names and appearances deceive you, because there’s a lot more here than meets the eye.
Fun Facts
P. arenarius is frequently used in commercial mycorrhizal inoculants (products used to boost plant health) due to the fungus’s capacity to form mutualistic relationships with a wide array of plant species. The area in which I found these used to be a gravel mine, and it’s now being restored to a sandy grassland. The fungus is an early colonizer of the sandy soil and is helping to reestablish both plant and fungal life. It should also be noted that these beneficial fungi will show up without the need to introduce them via a spray or product.
The mushroom is also used as a natural dye for wool and other textiles — hence the least offensive common name, “dyeball”. The mushroom dyes the fabrics a reddish-brown to black. A quick search online shows that folks are selling these fungi for dyeing purposes at around ~$15/ounce. Forget gold and silver, it’s time to diversify the portfolio with dyeballs.
A quick note on the other common names: the dog turd moniker originated at a foray where the late Tom Volk watched a grad student, who thought they’d actually found dog poop, try to show this to a professor as a prank. Of course, the professor recognized the mushroom immediately, and now the student looked silly. Hey, the joke might not have worked, but the name stuck. “Dead man’s foot” is another name based on appearance, and while I’ve seen enough dog feces to say there is somewhat of a resemblance there, I fortunately have no experience with this subject.
A comprehensive review out of Portugal looked at the antimicrobial, antifungal, and even anticancer potential of different species of Pisolithus (Reference 2). The researchers noted that potent antimicrobial compounds were found in the fruiting body, not so much the mycelium, and while these compounds were effective against both Gram-positive and Gram-negative bacteria, they were especially effective against drug-resistant bacteria sourced from the “wound exudates of hospitalized patients”. That’s a job for the intern if there’s ever been one.
Researchers noted the compound pisosterol, found in the dyeballs, displayed strong antitumor properties against an array of cancers. Not only did the compound induce apoptosis in cancer cells, but it did not affect the functioning of any healthy blood cells. There is a lot of promising research with certain compounds in the fungus, and the next step would be to do these tests in humans (clinical trials), rather than just in the lab.
Etymology
`The genus Pisolithus is derived from Greek and breaks down to píso which means “pea”, and líthos, which means “stone”. The pea-stones refers to the small nodules, or peridioles (spore packets) inside the mushroom. As they mature from the top of the mushroom down, they turn into mature brown spores, and are blown away by the wind.
The species epithet arenarius comes from Latin and means “sand-dwelling”, a reference to the preferred habitat of these mushrooms. You will also find them in lawns, gravel, roadside drainage ditches, and other disturbed areas.
Ecology
Despite the unsavory appearance, the fungus serves an important role in the soil as a promiscuous ectomycorrhizal partner with oaks, pines, and other plant species. Apparently, the fungus can associate with over forty different tree species. The ecto- in “ectomycorrhizal” means “outer” and refers to how the fungus (myco) wraps around the outside of the plant root (rhiza) to establish a mutualistic relationship and exchange nutrients. The mushrooms pop up mid-summer through fall, and can persist into the winter as the large spore masses slowly but surely dissipate in the wind.
The fungus used to be classified as Pisolithus arhizus, but that’s now recognized as a European/African species. North American dyeballs are now Pisolithus arenarius. It’s quite possible that there are multiple species on the continent, the Rocky Mountains tend to be a large divide that causes speciation on either side, and we’ll need DNA sequencing to elucidate that for us.
Speaking of which, this week you can send any mushroom you’d like to have sequenced to MycotaLabs where they will sequence your mushroom for free (there is a suggested donation of $3/sample). The Cape Cod Mycological Society just processed 96 samples that we are sending in for sequencing.
Upcoming Events
I’m facilitating a couple mushroom cultivation workshops this weekend: one with Dennis Conservation Land Trust and the other with Resilient Roots.
It also looks like I’ll be doing another walk on Friday with the 300 Committee (the land trust that helps restore the preserve where I found these dyeballs). Email saveland@300committee.org with the subject “Mushroom List” and you will be alerted when the details are confirmed.
On Sunday at 10AM the Cape Cod Mycological Society is doing a walk at the Ashumet Holly Wildlife Sanctuary.
Mid to late October is Matsutake season on Cape Cod, and the CCMS went looking for them this past weekend. Unfortunately we have to wait until next week to take a look at what we found. Until then, keep your eyes peeled for whatever mushrooms you may find after the recent rain.
New moon today,
Aubrey
References:
Kuo, M. (2019, August). Pisolithus arenarius. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/pisolithus_arenarius.html
Oliveira RS, Preto M, Santos G, Silva AM, Vasconcelos V, Martins R. Exploring the Bioactive Potential of Pisolithus (Basidiomycota): Comprehensive Insights into Antimicrobial, Anticancer, and Antioxidant Properties for Innovative Applications. Microorganisms. 2024 Feb 23;12(3):450. doi: 10.3390/microorganisms12030450. PMID: 38543501; PMCID: PMC10972124.
https://www.savebuzzardsbay.org/places-to-go/breivogel-ponds-conservation-area/
https://www.inaturalist.org/taxa/1127196-Pisolithus-arenarius