Jelly Ear

Description

The jelly ear is a gelatinous, brown mushroom shaped like an ear or a cup, usually 2-10 cm across. The upper side is matt, finely downy, reddish-brown with a violet tinge, the underside smoother and paler, often with veins. In damp conditions it is elastic and translucent, in drought it hardens and darkens, but it revives after rain.

It grows on dead and weakened branches of broadleaved trees, most often on elder, throughout the year, especially in autumn, often in clusters. It is common in Poland and is not protected.

It is distinguished from the tripe fungus (Auricularia mesenterica) by the hairy, zoned upper surface of the latter. In Europe it is little valued because of its bland taste, but related species are used in Asian cuisine. If you are not sure of the species, do not pick or eat it.

Identification features

Cap

Fruiting body 2-10 cm (some descriptions give up to 9 cm) across and up to 3 mm thick, ear-shaped, cup-shaped or goblet-shaped, at first goblet-shaped, later disc-shaped, bent and veined-ribbed; attached sideways or by a very short stalk. Upper surface matt, finely suede-like or frosted (tiny grey hairs 100-150 µm), reddish-brown with a violet tinge, darkening with age. In damp weather gelatinous and translucent; in drought hard, corky or horny, dark (blackish-brown to blackish-grey), and after rain it becomes gelatinous again. Entirely white forms occur (the former A. lactea).

Hymenophore (underside of the cap)

The hymenium is on the lower surface of the fruiting body: smooth or folded, reddish-brown to greyish-brown, shiny, sometimes with "veins"; whitish from spores in mature specimens. No gills or tubes.

Stem

No stem or a very short stalk; the fruiting body is attached sideways to the substrate.

Flesh

Thin, gelatinous-springy, odourless, mild, bland in taste; hard and brittle when dried. (Do not taste the flesh of unidentified mushrooms.)

Spore print and spores

Spore print white, non-amyloid. Spores spindle-sausage-shaped (allantoid), size 15-23 × 5-7 µm (descriptions give different ranges). It discharges up to several hundred thousand spores per hour, even after drying out.

Habitat and distribution

Ecology. Saprotroph on dead wood or a weak parasite of living wood, causing white rot. Grows on branches and trunks of broadleaved trees and shrubs, most often on elder, also on maples, beeches, ashes, alders, spindle; exceptionally on conifers. Occurs in forests, thickets, parks, gardens and along roads; singly or in groups and clusters, especially in prolonged damp conditions.

Distribution. Formerly considered cosmopolitan; after genetic revision only Europe (other species occur outside Europe; accounts differ). Common in Poland. Not legally protected in Poland.

Fruiting. Throughout the year, most often in autumn; also in mild winters, from late spring on stumps and trunks.

What can it be confused with?

• Auricularia mesenterica (tripe fungus) — Upper surface hairy and zoned.
• Auricularia cerrina — European, recently described from oak (Czechia); fruiting bodies dark grey to almost black.
• Auricularia heimuer (Asia), Auricularia angiospermarum (Americas) — Very similar; microscopic differences: shorter basidia and spores (11-13 × 4-5 µm; 13-15 × 4.8-5.5 µm).

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

• The epithet judae is linked to the belief that Judas hanged himself on an elder tree; the name "Jew's ear" came from a mistranslation of "Judas's ear" (in English since 1544), and the British Mycological Society recommends the name "jelly ear".
• A dried fruiting body loses as much as about 90% of its mass, but still releases a small number of spores, and after rain it regains its springiness.
• In 2020 about 1 million tonnes of Auricularia mushrooms were produced in China, making it the second most cultivated mushroom there; the cultivated "jelly ear" is, however, A. heimuer.
• It is mentioned by Marlowe in "The Jew of Malta"; it probably also inspired an Emily Dickinson poem about a mushroom.