Today we’ll stay in Paris and look at the one fresh, non-cultivated mushroom we found during our stay. We found this mushroom in one of the city’s main parks, Bois de Boulogne, as we were scoping out the park to see how it stacked up against Central Park. The park features the site of the French Open (Roland Garros) at the southern end, two horse racing tracks, a chateau, and a variety of woods and formal gardens throughout the 2,155 acres (873 hectares).
While walking through a wooded area one log stuck out amidst the grays of winter woods, and upon closer inspection revealed a fresh fruiting of this mysterious Stereum species. I went down a rabbit hole to try to identify this species as I sifted through comments on iNaturalist and read academic papers on the distribution of Stereum in Yugoslavia in 1971. I flipped and flopped on the identification of this mushroom before narrowing it down to two Stereum species: Stereum insignitum and Stereum subtomentosum.
A few months ago I wrote about three Stereum species you’ll find in eastern North America, and one of those species is S. subtomentosum which, I now know, is also found in Europe. Stereum are some of the most common mushrooms you’ll find in the woods across Europe and North America, but they are quite difficult to identify to species. My own identification of Stereum subtomentosum is tentative, but we’ll put the taxonomy aside and see if we can’t learn a little more about these European “false turkey tail” fungi.
Fun Facts
Not too much information is available about Stereum insignitum other than the fungus was formally described in 1890 by the French mycologist Lucien Quélet. Quélet was a renowned European mycologist (he has a genus, Queletia, named after him) and in 1884 he helped establish the Société Mycologique de France which is regarded as the first mushroom club in the world.
Stereum subtomentosum was first described by a Czech mycologist named Zdeněk Pouzar who had a few hundred described species to his name. A few of the key identification characteristics for this mushroom include a yellowing of the underside when wet, hairs that stick up on the cap (rather than being matted down), and pronounced ridges/undulations of the hairy bands on the cap.
A study out of Serbia showed that S. subtomentosum has a strong antioxidant profile and antiproliferative capabilities (the ability to suppress cell growth) as well. (Reference 2)
During my research of other European Stereum, I came across a study on Stereum hirsutum out of Italy that examined the fungus’s ability to degrade Bisphenol A (BPA). This chemical is used in a wide range of plastics and its ubiquity has led it to now be found floating in humans as well.
BPA mimics estrogen in the body and can potentially interrupt normal hormone functions as well as lead to other negative impacts on our health. Fortunately, S. hirsutum was able to break down all the BPAs in an aqueous solution after ten days, while turkey tail (Trametes versicolor) actually broke the BPAs down in just seven days. (Reference 3)
Ecology
This species of Stereum is saprobic (decomposes the dead wood of hardwoods) and possibly endophytic (lives as a symbiont within the tree when the tree is alive). Stereum insignitum is found more in Southern Europe, around the Mediterranean, but also in Colombia (?), while S. subtomentosum has a broad distribution across Europe and eastern North America. These mushrooms can grow year round — the specimen I found was fresh in February.
I say these mushrooms were “fresh” because they were still rubbery and malleable. Older specimens will lose this ochre color and become brittle. Instead of bending, they’ll snap in half. This change in color and texture leads to even more difficulty in proper ID and is certainly one of the reasons why we barely understand some of the most common mushrooms in the woods.
Events
I imagine other events will pop up but here’s what the spring looks like so far:
5/18: Adventure Day with the Darien Land Trust in Darien, CT (great for families with young kids.)
Alright, this MM chewed me up and spit me out. We’ll see if we can find something a little more straight forward for next week. Also, I may be biased but I prefer Central Park to Bois de Boulogne anyway,
Aubrey
References:
Rašeta M, Popović M, Knežević P, Šibul F, Kaišarević S, Karaman M. Bioactive Phenolic Compounds of Two Medicinal Mushroom Species Trametes versicolor and Stereum subtomentosum as Antioxidant and Antiproliferative Agents. Chem Biodivers. 2020 Dec;17(12):e2000683. doi: 10.1002/cbdv.202000683. Epub 2020 Nov 17. PMID: 33058392.
Traversa A, Loffredo E, Gattullo CE, Senesi N. Biodecontamination of aqueous substrates from bisphenol A by ligninolytic fungi. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2012;47(10):1407-12. doi: 10.1080/10934529.2012.672317. PMID: 22571528.
https://www.inaturalist.org/taxa/155081-Stereum-subtomentosum
https://www.mycoguide.com/guide/fungi/basi/agar/russ/ster/ster