Fomes fomentarius

Cap: Perennial, pileate, tenacious, tough-woody, firmly attached.

Pileus: 6-20 cm overhanging, 3-15(25) cm wide, 2-10(15) cm thick at the base, sessile, attached over the entire width, occasionally convex and circular or with a rounded protrusion above, quickly indurated, with a cuticle of ± 1 mm thickness, hard, glabrous, smooth, not cracked, zoned and concentrically furrowed with ash brown or gray towards the substrate, in various tones of gray or bluish gray at the base, with older part gray and the marginal zone pale brown during active growth, with a straight to slightly undulating margin, finely tomentose, pale brown and then grayish brown with age.

Pore Surface: Concave, powdery, pale brown to yellowish-brown, darkening on bruising.

Pores: Round, 3-5 per mm, with thick and entire dissepiments, tomentose.

Tube Layer(s): Indistinctly stratified, forming the majority of the internal tissue of the basidiome, pale brown to reddish-brown, becoming filled with white mycelium, 2-6 mm in length for each layer.

Context: Tough-fibrous, often relatively thin between the pileus cuticle and the old tube layers, unzoned, yellowish-brown, with granular core of variable size formed on the upper part, marbled with pale and darker areas, up to 2.5 cm thick in total.

Odor and Taste: Delicate and pleasant odor, especially during sporulation, fleeting banana-like smell when cut fresh, and bitter taste.

Spore Print: Whitish to pale yellow.

Basidia: Club-shaped to urn-shaped, swollen at the base, with 4 sterigmata, looped at the base, 23-25 x 7-9 µm, formed only early in the spring.

Spores: Cylindrical, smooth, thin-walled, hyaline, inactive in Melzer's, 12–18(20) x 4–7 μm, Q = (2.5)3.0–3.5(3.6), often produced in large quantities in the spring, covering the surrounding area of the basidiome with a remarkable white powder, difficult to observe the rest of the year.

Cystidia: Absent.

Cystidioles: Often present, fusiform, looped at the base, thin-walled, 24-37 x 3.5-7.5 µm.

Hyphoid Elements: Present on the edge of the dissepiments, sometimes slightly encrusted, up to 120 x 3-5 µm, emerging up to 55 µm.

Growth Mode: Solitary or in groups of 2-10 juxtaposed or partially fused caps; the latter present bistourned forms that adapt by geotropism to changes in the tree's position.

Substrate and Decay Type: Saprotrophic, on living or dead hardwoods, especially birch and beech, also on hickory, cherry, oak, maple, ash, elm, and poplar; on trunks, more rarely at the base of trees or on stumps. White-rot decay agent. Common especially on Betula, Alnus, and Fagus, occasionally on conifers such as Abies and Larix. Acer, Alnus, Betula, Carpinus, Carya, Fagus, Fraxinus, Juglans, Larix, Malus, Populus, Prunus, Pseudotsuga, Pyrus, Quercus, Salix, Sorbus, Tilia, Tsuga, Umbellularia, Ulmus.

Fruiting Period: Summer or fall.

Frequency: Common.

Edibility: Non-edible.

Chemical Reactions:

• Darkens and then turns brown in KOH on the context.

Remarks: This polypore is characterized by its lobed basidiomes, often grayish pileus, with a hard, glabrous, and concentrically furrowed cuticle. The granular core at the base of the context immediately distinguishes it from species in the Ganoderma genus. Worn specimens weathered by Fomitopsis mounceae may resemble it, but the granular core is absent in the latter, and the pileus cuticle melts in heat instead of carbonizing as in F. fomentarius. F. fasciatus closely resembles it but is tropical to subtropical in North America, and its spores are smaller. The granular core sclereids of both species are very distinct microscopically. They were not mentioned in the early descriptions. Unless harvested in spring, F. fomentarius basidiomes are invariably sterile. The reason for this seasonal sporulation is unknown. F. fomentarius seems to form two distinct lineages in Europe and North America. A better name for our species might be F. excavatus, which was originally a variety of F. fomentarius described from Western Canada.

In historical times, pieces of Fomes fomentarius were used as tinder. These pieces, soaked in a solution of saltpeter until saturated and then dried carefully, formed amadou. This material could catch a spark and was used to start fires.
Fomes fomentarius has been traditionally used for its medicinal properties, and some potential health benefits have been attributed to this mushroom. It's important to note that while there is historical and cultural use, scientific research is ongoing, and not all traditional uses have been scientifically validated. Here are some aspects related to the medicinal usage of Fomes fomentarius:

1. Anti-Inflammatory Properties:

   • Compounds found in Fomes fomentarius have demonstrated anti-inflammatory effects. This property can be beneficial in managing inflammatory conditions.

2. Antioxidant Activity:

   • The mushroom contains antioxidants that can neutralize harmful free radicals in the body. Antioxidants play a role in supporting overall health and may help reduce oxidative stress.

3. Immune System Support:

   • Some studies suggest that Fomes fomentarius extracts may have immunomodulatory effects, potentially supporting the immune system.

4. Antiviral and Antibacterial Properties:

   • Certain compounds in the mushroom may exhibit antiviral and antibacterial activities, which could be relevant in preventing or managing infections.

5. Wound Healing:

   • Historically, the amadou derived from Fomes fomentarius was used as wound dressings due to its absorbent and sterile properties. While not a direct medicinal use, this practical application contributed to survival and healing.

6. Adaptogenic Properties:

   • Adaptogens are substances that may help the body adapt to stressors. Some mushrooms, including Fomes fomentarius, are being studied for potential adaptogenic effects.

7. Anti-Cancer Potential:

   • Preliminary research suggests that certain compounds in Fomes fomentarius may have anti-cancer properties. However, more research is needed to understand the mechanisms and potential applications.

8. Anti-Diabetic Effects:

   • Some studies indicate that Fomes fomentarius may have effects on blood sugar levels, which could be relevant in managing diabetes.

References:

• MycoMatch (MatchMaker) Mushrooms of the Pacific Northwest, Version 2.4.1. 2023.
• Ginns, J. (2017). Polypores of British Columbia (Fungi: Basidiomycota). Technical report 1014.
• Gilbertson, R.L. & Ryvarden, L. (1986). North American Polypores Vol. I. Fungiflora.