Golden Ear Identification Guide

The first impression

You are working a fallen hardwood branch or a dead standing oak limb, probably in autumn or during a mild wet spell in winter, and there is a clot of intense orange-gold jelly clinging to the bark. It is 2 to 8 cm across, lobed and folded like a small brain or a bunched-up piece of chamois, glistening if it has rained recently and shrunken into a hard varnish-like scab if it has not. Your instinct will be to call it Yellow Brain, and about half the time in most woodlands that instinct is right. Golden Ear is the other half, and the way to tell them apart has almost nothing to do with the jelly itself.

Golden Ear is a mycoparasite: it does not decay wood on its own account, it attacks the mycelium of another wood-rotting fungus and fruits out of its host's fruitbodies. Its host is Hairy Curtain Crust, Stereum hirsutum. So identification becomes an exercise in finding the host, and everything else is corroboration. Modern classifications often place this species in the genus Naematelia, but the field workflow is unchanged.

Working through the fruitbody

Overall shape and texture. Irregular cushions and rosettes of thick, blunt, convoluted lobes, more compact and more three-dimensional than a flat jelly crust. Fresh material is firm and rubbery rather than slack, with a springy resistance when you press it. It is noticeably tougher than most yellow jellies, and a lobe pulled off tends to snap back rather than sag.

Colour. A deep, saturated golden-yellow to orange-yellow, often more egg-yolk than lemon, and usually slightly deeper toward the interior of the mass. Sun-exposed lobes bleach to pale amber. Dried material shrinks to a hard, dark orange-brown crust that revives and re-inflates almost completely after rain, a normal and repeatable trait of these jelly fungi.

The internal core. Slice a fresh cushion vertically. Golden Ear typically shows a paler, denser, whitish core running through the base of the lobes, which is host tissue and hyphae bound into the jelly. That pale core is one of the better field cues you can obtain without a microscope.

Attachment and base. This is the decisive step. Cut or pry the jelly away from the bark and look at the wood underneath. You are looking for small, thin, leathery brackets in overlapping tiers, hairy and zoned grey-buff on top, smooth and yellow-orange to buff underneath: Hairy Curtain Crust. Frequently you will find the jelly literally erupting through the middle of a crust bracket, or ringed by them. Where the host is present, the identification is close to settled.

Spore-bearing surface. There are no gills, pores or teeth. The entire outer surface of the lobes is fertile and smooth. Nothing to dissect here, only to observe.

Flesh and colour change. Gelatinous throughout, translucent when wet, with no latex, no milk and no bruising reaction. Handling does not stain your fingers, and cut surfaces do not change colour.

Taking a spore print

Jelly fungi will give you a print, but they need help. Cut a fresh, fully hydrated lobe, set it on a glass slide or dark card, and cover it with a glass or a plastic tub so the humidity stays high. Leave it several hours or overnight in a cool room. What you get is a thin, whitish to very pale yellow deposit, sparse compared with the dense print of a gilled mushroom. If the material has dried at all it will produce nothing, so rehydrate briefly in a damp chamber first.

Under a microscope, the diagnostic feature of the genus is the basidium: it is divided longitudinally into four cells, like a hot cross bun in cross-section, rather than being a simple club. Any yellow jelly with cruciately septate basidia is a Tremella or close relative; the tuning-fork shaped basidia of the Dacrymyces group are a completely different structure and can be resolved at 400x. Spores are broadly ellipsoid to subglobose, smooth and colourless.

Substrate, host and season

Golden Ear is a hardwood species, strongly associated with oak but also found on beech, birch, hazel and other broadleaved wood. It fruits on dead attached branches, fallen limbs and stumps, wherever Hairy Curtain Crust is established. It is favoured by mild wet weather and shows up mainly from late summer through winter in temperate regions, persisting through freeze-thaw cycles by drying down and rehydrating. It is widespread across North America, Europe and Asia.

Telling it from its look-alikes

Yellow Brain (Tremella mesenterica). The main confusion. It parasitises Peniophora species instead, so the host beneath is a smooth, thin, pinkish-grey to purplish crust rather than a hairy tiered bracket. Yellow Brain is usually paler and more translucent, with thinner, floppier, more wave-like lobes that sag under their own weight, and it lacks the dense whitish internal core. Golden Ear is firmer, deeper coloured and more compactly convoluted.

Witch's Butter of conifers (Dacrymyces chrysospermus). Grows on conifer wood, often on barkless logs, and has a conspicuous white attachment point where it grips the wood. Its lobes are more orange and it is a wood decayer rather than a parasite of another fungus. Tuning-fork basidia settle it under the lens.

Dacrymyces stillatus. Small, scattered, gummy orange blobs a few millimetres across on conifer and hardwood, never building into large lobed cushions.

Tremella foliacea and relatives. Brown to reddish-brown leafy jellies, quite different in colour.

Slime moulds. Bright orange aethalia of Fuligo and similar organisms can fool you at ten paces, but they are chalky or powdery when touched, not rubbery, and they collapse rather than flex.

A field routine that works

Do not identify the jelly. Identify the wood, then the crust fungus on the wood, then the jelly. If you find hairy zoned brackets with a yellow-orange underside all around and beneath your golden mass, and the mass is firm with a pale core, you are on Golden Ear. If the crust beneath is smooth and pinkish, you are on Yellow Brain. Photograph both the jelly and the surrounding bark surface before you remove anything, because once the specimen is in a bag that host context is gone for good.