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Northern Red Belt - Fomitopsis mounceae

Good evening, friends, and happy President's Day.

This week's mushroom is the Northern Red Belt (Fomitopsis mounceae). I found this mushroom while hiking up near Sugarloaf Mountain in the White Mountain National Forest this weekend. Fortunately, we can find this puckish polypore closer to home as it grows in New York's mountainous areas (the Catskills and Adirondacks) and mountainous areas throughout the entire Appalachian Range. Let's look at some distinct features of this specimen and compare it to some sister species, one of which I found further up the trail.

Fomitopsis mounceae

Fun Facts

This mushroom used to be included in the Fomitopsis pinicola species complex (a group of mushrooms that are genetically similar and hard to distinguish between), but DNA sequencing has since revealed F. pinicola is strictly a Eurasian species. There is, however, quite a bit of research on the use of F. pinicola as a medicinal mushroom with both in vivo (in the body) and in vitro (in the lab) studies that show it possesses antioxidant, anti-cancer, and anti-inflammatory properties (check out Reference 3 if you're curious). While F. pinicola is a distinct species (the authors note all the mushrooms used for the research came from Europe or Asia), the species is so closely related to F. mounceae that they likely share a lot of the same biochemistry and ipso facto the same medicinal properties. I may try to harvest some next time I see it.

This mushroom has a pretty strong odor. When I found it in the Catskills, and again as I finagled my nose under it this go-round, I picked up on a lemony, chemical kind of odor - almost like a cleaning product. I actually like the smell though, although others seem to find it unpleasant, but this is a specific characteristic I've noticed both times I've found the species (the other time I found it was in the Catskills).

Fomitopsis mounceae

Notice the stick jutting through mushroom above. This is an example of indeterminate growth, a feature many polypores possess where they are able to grow around, and encapsulate, surrounding objects - usually sticks or plants. I also have a hypothesis that the cracked, white dust on the cap above is a different fungus entirely, probably a yeast of some sort. The cap colors of F. mounceae can range from entirely red/orange (like in our specimen) when young to a dark brown cap with just a slight band of red near the margin (the outer edge) with age. As is the case in almost all mushrooms, there are exceptions to the rule, and some specimens of F. mounceae don't have any red at all.

Fomitopsis mounceae


This species is saprobic and creates a brown rot on both conifers and hardwoods. Michael Kuo of points out that brown rot residue is an import component in the soil nutrients of conifer ecosystems, and our specimen was both growing on a conifer and part of a large coniferous forest. A mere snapshot of the vastly intertwined and intricate web that is forest ecology.

This species has several look-a-likes. One species we see more commonly in NYC and the surrounding area is Ganoderma sessile. The largest similarity between the two is that they both have a red-shellacked cap at various stages of their growth. However, G. sessile has a more southernly and cosmopolitan distribution. From personal experience it's not as thick as F. mounceae and forms larger, thinner brackets,. Here's a pic of G. sessile:

Ganoderma sessile

The other species you might confuse for F. mounceae I saw on the very same walk. Fomitopsis ochracea is a similarly shaped polypore from the same genus, but the difference is that it is known as the "American Brown Fomitopsis" suggesting that it is brown, lacking that red varnish, and also patriotic. The "American" actually indicates that it's an exclusively North American species, as is F. mounceae. As previously noted, DNA sequencing distinguished both of these North American species from the Eurasian species Fomitopsis pinicola. DNA testing revealed that another distinct species, Fomitopsis schrenkii, is almost identical to F. mounceae but grows west of the Rockies. Below are a couple photos of F. ochracea, with which we can compare with the red F. mounceae. It should be noted that F. ochracea is less common and typically found at higher elevations (consistent with this finding) than F. mounceae.

Fomitopsis ochracea

Notice the distinctly brown, rough cap. It lacks that sort of shine or "shellac" that gives F. mounceae a varnished appearance. In fact, in a New York Mycological Society zoom ID session I learned a field test to distinguish the two. If you burn the outer edge of F. mounceae the mushroom melts, whereas F. ochracea burns. From my understanding, the chemicals in F. mounceae that melt are the same chemicals that create that glossy, shiny red cap.

Fomitopsis ochracea

No rest for the wicked. In an attempt to outdo this past weekend's trip to a colder and darker locale, next weekend I'll be in Maine. It's likely that next week will also feature a winter polypore that I find up there.

Until then,



1) Kuo, M. (2022, June). Fomitopsis mounceae. Retrieved from the MushroomExpert.Com Web site:

3) Bishop KS. Characterisation of Extracts and Anti-Cancer Activities of Fomitopsis pinicola. Nutrients. 2020 Feb 26;12(3):609. doi: 10.3390/nu12030609. PMID: 32110892; PMCID: PMC7146440.


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