Golden Ear

Golden Ear (Tremella aurantia) is a robust orange jelly fungus that grows in clusters of thick, curling lobes on dead broadleaved wood. It is closely related to the better-known Yellow Brain but tends to be deeper in colour, firmer in texture and more clearly built from a small number of broad, ear-like or petal-like lobes rather than a dense tangle of narrow folds.

Like other members of Tremella, it is a mycoparasite. Its particular host is Stereum hirsutum, the Hairy Curtain Crust, and the two are almost always found within a few centimetres of one another on the same log. Because Stereum hirsutum is itself bright yellow-orange when fresh, the pair can be confusing at first glance, but the flat, leathery, hairy brackets of the host contrast sharply with the swollen, translucent jelly of the parasite.

The species is widespread in North America and eastern Asia and is recorded, though less commonly, in Europe. It is a good example of how identifying a jelly fungus often depends as much on recognising what else is growing on the wood as on the jelly itself.

Fruiting body

Clustered gelatinous masses 2–8 cm across, made up of relatively few thick lobes that curl and fold like petals, ears or crumpled ribbons. Compared with Yellow Brain the whole structure is chunkier, with thicker tissue and a slightly less watery, more rubbery feel. It holds its shape well when lifted.

Colour

Deep golden-orange to orange, often with a slightly duller or more brownish cast than the clear egg-yolk yellow of Tremella mesenterica. The colour is fairly uniform across the lobes and deepens as the tissue begins to dry, eventually shrinking to a dark orange-brown crust.

Attachment and flesh

Attached to the wood at a narrow base, frequently emerging directly beside or even from among the brackets of the host crust. Flesh gelatinous but noticeably firm, translucent when held to the light. No ring, volva or true stipe. Cut surfaces do not develop a new stain colour.

Spore print

White. As with all jelly fungi, the whole exposed surface is fertile rather than a defined underside.

Golden Ear occurs on dead broadleaved wood, especially oak, and shows a strong preference for fallen logs, stumps and large branches lying on the ground rather than small twigs still in the canopy. The single most useful habitat clue is the presence of Stereum hirsutum on the same piece of wood, forming thin, hairy, orange-and-buff banded brackets and resupinate sheets.

Fruiting is concentrated in autumn and early winter, with fruiting bodies persisting through mild spells and rehydrating after rain. It is common in eastern North America, well recorded in Japan and China, and scattered but genuine in parts of Europe.

Tremella aurantia parasitises the mycelium of Stereum hirsutum, penetrating its hyphae and drawing nutrients from them. The wood decay itself is carried out by the Stereum, a white-rot fungus, while the Tremella simply taps into that established network. This makes Golden Ear an obligate associate: it cannot be found without its host somewhere in the same substrate.

The gelatinous fruiting body is an adaptation for intermittent moisture. It can dry to a hard film and revive repeatedly, extending the period over which spores are shed from a single fruiting. Spores are produced across the whole outer surface and, characteristically for the genus, can germinate into budding yeast-like cells that survive independently until they encounter a suitable host colony.

Tremella mesenterica (Yellow Brain) is the closest match: it is a brighter, purer yellow, softer and more watery, built from many narrow crowded folds, and grows in association with smooth Peniophora crusts on attached branches rather than with hairy Stereum brackets on logs. Dacrymyces chrysospermus (Orange Jelly) favours barkless conifer wood and shows a whitish rooting attachment point.

Guepinia helvelloides (Apricot Jelly) is pinkish-salmon rather than golden and forms distinct funnel- or tongue-shaped structures with a stalk-like base, quite unlike the clustered lobes here. Stereum hirsutum itself, when very fresh and wet, can look surprisingly bright, but it is a thin, flat, leathery bracket with a velvety upper surface, not a swollen translucent jelly.