Hoof Fungus

Description

The hoof fungus is a hard, perennial, hoof-shaped bracket fungus up to several dozen centimetres wide. The top is covered with a grey to blackish, matt crust with concentric growth rings; the margin is whitish and blunt, and the underside has fine, round pores, cream to brown.

It grows all year round on the trunks of old, weakened broadleaf trees, most often beeches and birches. It is very common throughout Poland, in forests of all types.

Older specimens of the red belted conk are similar to it; they are distinguished by the pore colour and the match test (the crust of the hoof fungus chars, that of the red belted conk melts). It is an inedible fungus.

Identification features

Cap

Fruiting body perennial; width up to 50 cm (descriptions give different ranges), thickness up to 25 cm, initially bulbous, later hoof-shaped or bracket-shaped, broadly attached. Upper side covered with a hard, non-cracking crust (1–2 mm), with concentric zones of annual growth; velvety, clay-coloured or reddish-brown in young ones, bare, matt, grey or blackish in older ones. Margin whitish (during the growth period), blunt. Colour variable: paler at lower latitudes and at altitude.

Hymenophore (underside of the cap)

Tubes in several layers, 2–7 mm long (also given in cm, probably erroneously), initially light orange, then orange-brown, finally ochre-brown or rusty-brown; pores round, 2–3 per mm, cream, turning brown with age and darkening when touched.

Stem

No stem; the fruiting body is broadly attached to the tree.

Flesh

Thickness 0.5–3 cm, rusty-brown or cinnamon, soft, corky-woody, fibrous, with a suede-like structure; smell slightly fruity, taste acrid. Never taste the flesh of unknown mushrooms.

Spore print and spores

Spore print white (spores are dispersed as a white dust in May and June), according to some descriptions the spores are lemon-yellow; non-amyloid, oblong-elliptical, smooth, 15–20(24) × 5–7 µm (descriptions give different ranges).

Habitat and distribution

Ecology. A saprotroph and weak parasite, causing white rot (decomposes cellulose, lignin and hemicellulose). Grows on the trunks of old, weakened broadleaf trees, especially beeches and birches, in riverside forests on poplar; infects through wounds, and after the tree dies it goes on developing for many years. It may also exist as a latent endophyte in healthy trees. The fruiting body grows from below (positive gravitropism); it lives up to 30 years.

Distribution. Northern Hemisphere: North America, Europe, Asia; according to some descriptions also Africa. Very common throughout Poland. No legal protection in Poland.

Fruiting. All year round (a perennial species); strongest growth from early summer to autumn; it disperses spores mainly in May and June.

What can it be confused with?

• Fomitopsis pinicola (red belted conk) — Brighter growth zone (yellow or orange-red), flesh red-brown, pores yellow. Match test: in the red belted conk the crust melts, in the hoof fungus it chars. Older specimens are difficult to tell apart.
• Phellinus hartigii (Hartig's conk) — Grows mainly on firs.
• Phellinus igniarius (willow bracket) — Grows mainly on willows. To tell the hoof fungus apart, the KOH test is used: a drop on the crust stains it dark red (presence of fomentariol).

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• Tinder (amadou), used to light fires since the Bronze Age, was made from the flesh; the name Fomes means tinder, and fomentarius means kindling.
• Ötzi, the Iceman from about 5000 years ago, had four pieces of the fruiting body with him, probably as tinder.
• Caps, waistcoats, gloves and ornaments were made from the caps; in Lesser Poland and Subcarpathia, on Holy Saturday dried bracket fungi called “fire fungi” were blessed, and according to belief they were to protect the house from lightning.
• The fruiting body lives up to 30 years, and the annual growth always forms from below, even when the tree is lying down.