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Violet-toothed Polypore - Trichaptum biforme

Good evening, friends,

We're no longer on island time for this week's mushroom, Trichaptum biforme, which is commonly known as the violet-toothed polypore. I featured this in my very first MushroomMonday, along with two other mushrooms, but this little polypore definitely deserves its own spotlight. It's not only one of the most common mushrooms in the park, but it's one of the most common in temperate forests throughout the northern hemisphere. It's also a good one to know this time of the year because the mushrooms persist throughout the winter. The specimen below was found in the ramble on 10/4/2021.

Trichaptum biforme

Fun Facts

One of the most unique features of this mushroom is that you can usually find another little mushroom growing on it - the small black ascomycete Phaeocalicium polyporaeum. Look for little pins sticking up from the concentric bands on the top of the mushroom. Technically, I don't think you're supposed to call ascomycete fruiting bodies "mushrooms", but we won't get caught up in the minutiae and instead we'll check out the fairy pins below:

Additionally, Trichaptum biforme mushrooms can be pulped into paper. Reference 4 is a fun article that talks about practical bushcraft uses for several common mushrooms in our area and I recommend giving it a scroll.

Trichaptum biforme


T. biforme is saprobic, growing on dead hardwood or creating a heartrot in standing trees. It is ubiquitous throughout North America, found in all 50 states, and is one of the most common fungi you will encounter in Central Park. It's frequently found on black cherry (prunus serotina) - the most common tree in the park. T. biforme fruits spring through fall - usually in clumped, overlapping shelves - but the mushrooms will persist through the winter meaning you can find them any time of the year. As they age they lose a lot of the violet color on their teeth and will usually just retain a purple band at the margin of the cap.

If the violet color gets completely bleached out, the evidence of teeth (those bumpy stalactites where spores are released, seen above) underneath the cap will help you differentiate this mushroom from similar mushrooms like turkey-tail, Trametes versicolor. T. biforme doesn't have the same medicinal properties as T. versicolor so it's good to know the difference in the two if you're trying to make a fungal tea or tincture.

Trichaptum biforme

Another look-a-like is Trichaptum abietinum, which is within the same genus, but this mushroom grows on conifer and tends to be smaller in size. A good rule of thumb is that if you find a violet-toothed mushroom on hardwood it's T. biforme, whereas if it's on conifer it'll require closer inspection. From my understanding T. biforme is predominantly on hardwoods and rarely on conifers while T. abietinum is exclusively on conifers. A "every square is a rectangle but not every rectangle is a square"- type situation. A picture of T. abietinum growing on dead hemlock (of which, due to the invasive woolly adelgid insect, there are too many) below:

Trichaptum biforme

T. abietinum is smaller in size and retains the purple coloring on its teeth longer than T. biforme.

MushroomMonday Presentation

Tomorrow at 7pm I'm giving a zoom presentation about MushroomMonday and some of my favorite finds for the Mid-Hudson Mycological Association. The MushroomMonday origin story, if you will. The presentation will be recorded and hopefully I'll be able to share it with everyone a little further down the road. If you're super keen on seeing it live you can join the MHMA for $15 here:

"Turn on, tune in, drop out" - Timothy Leary - me tomorrow at 7pm


1) Kuo, M. (2004, August). Trichaptum biforme. Retrieved from the MushroomExpert.Com Web site:


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