Cloud Ear Identification Guide

Standing in Front of It

The setting that produces Cloud Ear is warm, humid and shaded: lowland broadleaf forest, a plantation margin, a stream gully choked with fallen timber, or simply a neglected woodpile in a subtropical garden, a day or two after heavy rain. What catches the eye is not a mushroom outline at all. Along the flank of a dead branch, or in a row down a split in the bark of a standing dead trunk, sit clusters of floppy brown discs and shells that look stuck onto the wood rather than grown out of it. Wet, they gleam and look almost translucent at the margin; the whole colony quivers if you knock the log with your boot.

The decisive first test is tactile. Press a fingertip into one. The flesh gives like a firm rubber gasket and springs straight back, neither crumbling like a brittle gilled mushroom nor squashing like a soft bolete. That single sensation places the find among the jelly fungi and eliminates every agaric, bolete and polypore in one move. From there the identification is a short series of surface checks.

Overall Shape and Size

Individual fruit bodies run 2-10 cm across, occasionally larger where neighbours fuse into a compound sheet. They begin as small shallow cups clamped tight to the bark, then expand into ear-shaped, shell-shaped or irregularly lobed forms with a wavy margin that often rolls and folds back on itself. There is no stipe. Attachment is by a narrow point or a short lateral stub, usually off-centre or at the upper edge of the cup, which is exactly why a mature specimen hangs from the side of a branch like an ear. Colonies are typically crowded and tiered, and a productive branch may carry dozens of overlapping brackets in a line.

The Upper, Sterile Surface

The convex outer face is the sterile side, and it carries the character that names the species. Run a thumb across it: it feels dry and suede-like even while the rest of the fruit body is soaking wet. Under a hand lens the surface is covered with a dense pile of fine, stiff, colourless to grey hairs, closely set and standing more or less erect. Their combined effect is a matt greyish, olive-grey or ashen bloom over an underlying tan to date-brown ground colour, and in strong light the pile scatters the light so the back looks distinctly paler than the front. Rain beads on it instead of soaking in. In specimens that have been battered by repeated downpours the hairs mat down, so check several fruit bodies and read the character from the youngest, best-sheltered ones.

The Fertile Underside

Turn a fruit body over. The concave inner face is the spore-bearing surface, and it is fundamentally smooth: no gills, no pores, no teeth, no spines. At most it carries low folds, shallow ribs and a few net-like veins radiating from the attachment point, most obvious in older or larger specimens. The colour is purplish-brown, greyish-violet, or a deep date-brown, becoming greyer and duller as the fruit body dries. Fresh, it has a faint waxy sheen. The contrast between a hairy, greyish, matt back and a smooth, glossy, violet-brown face is the working field signature of the species.

Flesh, Section and Colour Change

Slice one across with a knife. The section is thin, roughly 0.5-2 mm, translucent and gelatinous, with a faintly layered structure visible against the light: a hairy outer zone, a denser gelatinous medulla and the fertile layer on the concave side. The texture is elastic and slightly tough rather than soft. There is no latex and no dramatic bruising reaction. Damaged or ageing tissue simply darkens gradually towards blackish-brown, and old fruit bodies can become almost black at the margin. If you find something that oozes, stains blue, or crumbles when cut, you are not looking at an Auricularia.

The Drying and Reviving Test

One of the most useful behaviours for confirming a wood-ear is reversible desiccation. In dry weather these fungi shrivel to hard, dark, almost black crusts glued to the bark, easily dismissed as tar, a scorch mark or a scrap of dead lichen. Wet such a crust with a squirt from a water bottle and wait a few minutes: it swells, softens and unfolds back into a recognisable ear, colour and all. This is a genuine field tool. It also explains why a log that looked bare in the dry season is suddenly covered in fruit bodies overnight after rain, without any new growth having taken place.

Taking a Spore Print

Jelly fungi drop spores slowly and grudgingly, so give the print time and humidity. Cut a fruit body free with a scrap of bark, lay it fertile-side (concave face) down on dark card or a sheet of glass, cover it with a bowl or tub to hold moisture, and leave it several hours to overnight. The deposit is white to whitish and often thin enough that you will only see it by tilting the card against the light. On glass it shows better. Under the microscope the spores settle the genus: smooth, colourless, cylindrical and strongly curved, sausage-shaped in profile, roughly 11-14 by 4-6 micrometres. That allantoid outline is unlike anything an agaric produces.

Substrate, Season and Setting

Cloud Ear is a saprotroph and a white-rot decayer of dead broadleaf wood. Look on fallen branches, stumps, logs, dead standing trunks and the dead limbs of living trees. It is overwhelmingly a hardwood species and is unusual on conifer, so a conifer log should make you reconsider. Its range is pantropical and subtropical, spilling into warm-temperate zones, and it fruits whenever humidity allows rather than in a strict autumn window: expect flushes within a day or two of substantial rain, in any month of a wet season. Shaded, sheltered wood that stays damp - the underside of a leaning trunk, timber lying on wet leaf litter - is far more productive than exposed, sun-baked logs.

Separating It from Look-alikes

Jelly Ear, Auricularia auricula-judae. The temperate counterpart, classically on elder. Its outer surface is finely downy at most and reads as matt but essentially smooth to the naked eye, never conspicuously hairy or greyed over, and its inner face is usually more strongly wrinkled and vein-networked. It also tends to a warmer reddish-tan brown.

Tripe Fungus, Auricularia mesenterica. Grows as shelving, tiered brackets in overlapping rows along a log rather than as separate hanging ears. Its upper surface is coarsely hairy and concentrically zoned in grey and brown bands, so from above it resembles a bracket fungus; the fertile underside is deeply wrinkled and purplish.

Witches Butter and relatives, Exidia species. Black or blackish, softer and more collapsing, forming blister-like or brain-like lobed masses rather than a defined cup or ear. Their surfaces are peppered with tiny pimple-like papillae, and there is no hairy sterile back.

Tremella species. Frilly, many-lobed and gelatinous throughout, white, yellow or orange, without any differentiated hairy surface. They also arise through the bark as parasites of other wood fungi rather than sitting as ears on the surface.

Young polypores and crusts. Any doubt is resolved by looking at the fertile surface with a lens: pores, or a firm corky texture, rule out Auricularia at once.

Within Auricularia itself several closely similar hairy-backed species occur in the tropics, and separating them reliably means measuring hair length and spore dimensions. Record the substrate, photograph the back in raking light, and dry a piece for later checking.