Tan Ear

Tan Ear is the plainest and most cup-like member of Otidea. Its fruiting bodies begin with the genus's characteristic lateral split and asymmetric growth, but rather than staying narrowly ear-shaped they expand into a broader, shallower, somewhat lopsided bowl, so the species sits visually between the true ear fungi and the ordinary cup fungi.

The colour is uniformly dull: leather-brown, greyish tan, pale clay or dingy ochre, with none of the yellow or pink of the Lemon Peel Fungus and none of the dark sepia of Toad's Ear. The Latin alutacea refers precisely to this soft leather colour.

Along with Hare's Ear it is one of the more commonly recorded members of the genus in temperate woodland, appearing through the autumn from a humus-rich forest floor, usually in small groups or loose clusters.

Fruiting body

At first ear-like and split from margin to base on one side, then expanding into an irregular, shallow, lopsided cup 2–8 cm across and up to about 6 cm tall. The margin becomes wavy and sometimes split further with age, and the whole structure often leans.

Surfaces

The inner surface is smooth and dull leather-brown, greyish tan or clay-coloured, sometimes with a faint olive or greyish cast. The outer surface is similar or slightly paler and finely mealy or scurfy, never hairy.

Stipe

The base narrows to a short, pale, stalk-like attachment, often whitish and coated in fine white mycelium binding soil and leaf fragments.

Flesh & spore print

The flesh is thin, pale brownish, firm and slightly pliant, tearing softly. No latex and no colour change on cutting. The spore print is white; spores are smooth and elliptical with two oil droplets, in the same size range as the other common ear fungi.

Tan Ear grows from soil, humus and leaf litter in deciduous and mixed woodland, and is also recorded from conifer stands. It favours shaded, moist, humus-rich ground, often appearing along path edges, in mossy hollows and on gentle wooded slopes, sometimes in loose troops of several fruiting bodies.

The fruiting season is late summer through autumn, sometimes persisting into early winter in mild regions. It is widespread across temperate Europe and North America and is one of the more regularly encountered Otidea species, though its drab colouring means it is often passed over.

This species inhabits the litter and humus layer of the forest floor and functions as a decomposer of leaves, needles and fine organic debris, in keeping with the rest of the genus. The white mycelial mat at the base of the fruiting bodies traces the colony's spread through the top few centimetres of the soil profile.

Even though the mature fruiting body opens out more than in its relatives, the lateral split and lopsided growth still tilt the hymenium away from the horizontal. This intermediate posture allows spores discharged from the asci to be carried off by air currents moving low over the litter, while the broader opening exposes a larger spore-producing surface than the narrow ear form allows.

Hare's Ear (Otidea leporina) is warmer tan to fox-brown, stays narrowly ear-shaped rather than opening into a bowl, and leans strongly towards conifer needle litter. Toad's Ear (Otidea bufonia) is much darker, dark brown to blackish, and thicker-fleshed. The Lemon Peel Fungus (Otidea onotica) is clearly yellow with a salmon-pink inner flush and a taller, more curled ear form.

Because Tan Ear opens out so much, the greater risk is confusing it with a brown Peziza such as the Common Brown Cup (Peziza phyllogena). Those form symmetrical bowls with brittle flesh that snaps cleanly and sit flat on the ground, whereas Tan Ear is pliant, lopsided, split down one side from the outset, and tapers to a distinct stalk-like base.