April 3, 2023
Good evening, friends,
This week’s mushroom is the Bicoloured Bracket (Gloeoporus dichrous). I’ve heard it pronounced “glow-eee-o-porus” and “glee-o-porus” so choose whichever is more phonetically palatable. This mushroom has a variety of common names, including the “Rubber Band fungus”, but I thought it was interesting that iNaturalist uses the UK spelling for “colour” in “bicoloured”. We found this mushroom growing on what I believe to be maple during the mushroom walk in Stamford a few weeks back. A curious little polypore, we’ll look at how you can identify this mushroom in the field and how you can distinguish it from similar species you may encounter.
One neat field identification trick for this polypore is that the reddish brown pore layer is elastic and will peel away from the cap. I didn’t know this when I found it, but I did find this helpful picture online from Gary Emberger, whose website I use pretty frequently.
There is one study that showed compounds within the fungus, known as calosporosides, inhibited the germination of the spores of two other fungal species. The ecological advantage of producing these compounds is fairly evident in that it the fungus prevents foreign fungal spores from germinating and subsequently digesting the same wood that G. dichrous inhabits and digests. It appears there is optimism that these compounds have the potential to be used pharmacologically as an anti-fungal drug.
The fungus is saprobic, decomposing dead wood – almost always hardwoods but occasionally conifers. The mushroom is typically white on top (when fresh) which contrasts with the fleshy, kidney colored pore surface. The mushroom grows late summer through fall and can last over winter – which is how we found it in the spring. The majority of sightings are in North America (coast to coast but predominantly east of the Rockies) but it appears to grow throughout temperate forests in the northern hemisphere from the UK across to Japan.
Similar species you’ll encounter in nearby parks and woods include Phlebia tremellosa and Bjerkandera adusta. Both P. tremellosa and our G. dichrous can adopt the same “effused-reflexed” growth pattern (where a majority of the fruiting body grows flat on the wood and just a small cap juts out). Additionally, the color of the underside is similar, but our Bicoloured Bracket has actual pores while P. tremellosa has gelatinous ridges and folds. The other similar species, B. adusta, shares the same white margin at the edge of the underside (seen above, along with the aforementioned pores), but it has a blue to grey coloring contrasted to the reddish brown of G. dichrous.
Back to the regular scheduled this week. Full moon and Passover on Wednesday night,
- Kuo, M. (2010, February). Gloeoporus dichrous. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/gloeoporus_dichrous.html
- Schüffler A, Liermann JC, Kolshorn H, Opatz T, Anke T. New caloporoside derivatives and their inhibition of fungal spore germination. Z Naturforsch C J Biosci. 2009 Jul-Aug;64(7-8):521-5. doi: 10.1515/znc-2009-7-810. PMID: 19791504. online: https://www.degruyter.com/document/doi/10.1515/znc-2009-7-810/html