The species produces very large polypore fruit bodies which are shaped like a horse's hoof and vary in colour from a silvery grey to almost black, though they are normally brown.

Though inedible, F. fomentarius has traditionally seen use as the main ingredient of amadou, a material used primarily as tinder, but also used to make clothing and other items.

The first scientific description of the fungus appeared in the literature in the 1753 Species Plantarum by Carl Linnaeus; he called it Boletus fomentarius.

[6] In 1818, Georg Friedrich Wilhelm Meyer described Polyporus fomentarius in his Primitiae Florae Essequeboensis,[7] and this name was sanctioned by Elias Magnus Fries in the 1821 publication of the first volume of his Systema Mycologicum.

[3] The upper surface is tough, bumpy,[10] hard and woody,[3] varying in colour, usually a light brown or grey.

The colour is typically lighter at lower latitudes and altitudes, as well as on fruit bodies in the Northern Hemisphere that grow on the south side of trees.

[3] Fomes fomentarius can easily be confused with Phellinus igniarius, species from the genus Ganoderma and Fomitopsis pinicola.

An easy way to differentiate F. fomentarius is by adding a drop of potassium hydroxide onto a small piece of the fruit body from the upper surface.

The solution will turn a dark blood red if the specimen is F. fomentarius, due to the presence of the chemical fomentariol.

[13] Fomes fomentarius has a circumboreal distribution, being found in both northern and southern Africa, throughout Asia and into eastern North America,[14] and throughout Europe,[12] and is frequently encountered.

[12] The species has also been known to grow upon maple,[12] cherry, hickory,[8] lime tree, poplar, willow, alder, hornbeam,[14] sycamore,[3] and even, exceptionally, softwoods,[14] such as conifers.

The species' mycelium penetrates the wood of trees through damaged bark or broken branches, causing rot in the host.

[13] The lines are caused by enzymes called phenoloxidases, converting either fungus or plant matter into melanin.

[13] Despite beginning as a parasite, the species is able to survive for a time (hastening decomposition) on fallen or felled trees as a saprotrophic feeder,[17] and typically lives there for years, until the log is completely destroyed.

This occurs even if the host tree has been laid on the forest floor,[20] which can happen because of the white rot induced by the fungus.

[14] The young fruit bodies are soaked in water before being cut into strips, and are then beaten and stretched, separating the fibres.