Wood Ear

Wood Ear belongs to Auricularia, a genus of jelly fungi in the order Auriculariales that produce thin, flexible, ear- or disc-shaped fruitbodies on wood. Unlike the brain-like Tremella jellies, Auricularia fruitbodies are laterally attached brackets with a clearly differentiated upper and lower surface, and their spore-bearing layer is the smooth or wrinkled inner face.

The species is one of the most weather-resistant fungi in temperate woodland. In dry spells the fruitbodies shrink to hard, dark, almost unnoticeable scabs pressed against the bark; after rain they rehydrate within hours and swell back into full translucent ears. This ability to dry and revive repeatedly means the same cluster can be watched on a branch for many months.

Modern work has split the old broad concept of Auricularia auricula-judae into several closely similar regional species, so European elder-loving material and East Asian or North American collections are not all strictly the same taxon. In the field they are separated only with difficulty, and all share the same distinctive ear form.

Fruiting body

Ear-, cup- or disc-shaped, 3-8 cm across (occasionally to 12 cm), attached to the wood at one point or by a very short narrowed stub. The body is thin - 1-3 mm - and translucent when wet, with an undulating, lobed and folded margin. Fruitbodies commonly overlap in tiers along the underside of a branch.

Surface

The inner (lower, spore-bearing) surface is smooth to strongly veined and wrinkled, often with rib-like folds that mimic the whorls of an ear; colour is tan, date-brown to purplish-brown, greying with age. The outer (upper) surface is a slightly paler greyish-brown and minutely downy or velvety, a texture best seen with a hand lens or by rubbing a fingertip across it.

Flesh & spore print

The flesh is gelatinous, elastic and rubbery, springing back when squeezed, and does not break cleanly like a normal mushroom - it tears. There is no stipe, ring or volva of any kind. The spore print is white and is easiest to obtain from a fully hydrated specimen; individual spores are sausage-shaped.

In Europe the classic host is elder (Sambucus nigra), where it fruits on dead and dying branches of living shrubs as well as on fallen wood. It also occurs on beech, sycamore, ash, spindle, willow and other hardwoods, and on old hedgerow stumps. Elsewhere in its range members of the group grow on a much wider variety of broadleaf trees.

Fruitbodies can be found in any month but are most abundant and best formed from autumn through mild winter and into early spring, when humidity is high and there is little competition. The fungus favours damp, shaded hedgerows, scrubby woodland edges, riverbanks and neglected gardens, and it is widespread across temperate Europe, with related species throughout Asia and the Americas.

Auricularia auricula-judae is a saprophyte and weak parasite that causes a white rot, decomposing lignin in the sapwood and bark of dead and moribund branches. On living elder it typically colonises limbs already stressed or killed by frost or breakage, then continues to fruit on the same wood long after the branch has fallen.

The rubbery, water-holding texture is a drought adaptation: gelatinised hyphal walls let the fruitbody survive repeated desiccation and resume spore release whenever the wood is wetted. Because it fruits in cold, damp conditions when few other fungi are active, it provides a winter habitat for mites, springtails and fungus gnats, and its decay work speeds the return of elder wood - which is soft and pithy to begin with - to the soil.

Auricularia mesenterica (Tripe Fungus) grows in overlapping shelves on elm and other hardwood stumps, and has a distinctly hairy, zoned grey-brown upper surface with a purplish, warty-veined underside; it is bracket-like rather than ear-shaped. Exidia glandulosa (Witches' Butter, black form) is black, blister-like and lumpy without a defined ear outline or a velvety outer face.

Witch's Butter (Tremella mesenterica) is bright yellow-orange and brain-like, with no distinction between an upper and lower surface. Dried-out Wood Ear can also be mistaken for a dark crust fungus or a scab of resin on the bark, but a few minutes of soaking restores the ear shape and elastic feel, which nothing else on elder does.