Jelly Tooth Identification Guide

Standing In Front Of It

Most encounters with the Jelly Tooth happen by accident. You are already crouched beside a mossy log in damp conifer forest, looking at something else, and there on the shaded flank of the wood is a smear of grey translucent jelly the size of a thumbnail or a small spoon. From standing height it reads as a slug, a lump of resin, or a shapeless Exidia. The character that settles the identification is on the underside, so the first move is always the same: get your eye below the specimen, or lift the whole piece of wood, and look up at it.

The setting is part of the identification. Pseudohydnum gelatinosum wants cool, humid, deeply shaded forest with wood that stays wet for weeks at a time. Think north-facing slopes, stream gullies, and old plantation edges where the litter is a continuous carpet of feather mosses. The wood beneath it is almost always coniferous, well past the bark-shedding stage, soft enough that a thumbnail sinks in, and frequently already filmed with green algae. When you find one you will usually find a dozen, scattered along the same log in a loose line following a crack or a bark seam.

Reading The Cap

The upper surface forms a shallow spoon, tongue, fan or bracket, typically 1 to 6 cm across, occasionally larger where several fuse into a lobed sheet. Colour runs the full range from near-white through smoky grey to grey-brown or almost blackish brown, and the darkness tracks light exposure rather than any change in the fungus itself: specimens deep inside a hollow log are noticeably paler than those on an exposed upper surface. Pure white forms occur regularly and are not a different fungus in any field sense.

Run a fingertip across the top. It should feel very finely velvety or minutely granular, not slimy, even though the whole body is soaked with water. Under a hand lens that texture resolves into a dense pile of tiny projecting hyphal tips. Now hold the specimen up against the sky. It should be genuinely translucent, so that you can see the outline of your finger through it. That combination of translucency with a matt, faintly downy upper skin is unusual and worth fixing in memory.

The Spore-Bearing Surface

Turn it over. The whole lower face is covered with soft, conical, translucent spines, 1 to 3 mm long, packed close but not touching, each tapering to a blunt point. They are the same watery grey-white as the rest of the fungus and they are perfectly flexible: brush them with a finger and they bend and spring back rather than snapping. Under a lens they look like a field of miniature icicles, or the surface of a cat's tongue.

Nothing else in a jelly-textured fungus does this. Every other gelatinous genus you are likely to meet on conifer wood presents a smooth, folded, brain-like or cup-like fertile surface, sometimes wrinkled or warted, but never true free-standing teeth. Conversely, every other toothed fungus you are likely to meet has firm, fibrous or corky flesh. The intersection of jelly and teeth is, in practice, a one-species intersection.

Stipe, Base And Attachment

The stipe is short, thick, and usually lateral or strongly off-centre, so the body sticks out sideways from the wood like a small tongue. Sometimes it is reduced to a broad point of attachment with no visible stalk at all; occasionally, on the upper face of a horizontal log, it is nearly central and the fungus looks like a tiny grey mushroom. The stalk is made of the same gelatinous material as the rest, not tougher, and it merges into the cap with no line of demarcation. At the very base, look for a small white pad of mycelium binding it into a bark crevice or a patch of soft decayed wood.

Flesh And Colour Change

Slice one vertically with a sharp knife. The cut face is uniform, watery, translucent and grey-white throughout, with a slightly firmer, more opaque core in the cap that carries the spines. There is no rind, no separate gelatinous cortex, no coloured zone. Press the cut edges together and they cling. Squeeze the whole body between thumb and finger: it compresses like a soft rubber eraser and returns almost fully to shape. It does not shatter, it releases no milk or coloured juice, and it does not bruise. That absence of any bruising reaction is real information — write "no change" in your notes deliberately rather than leaving the line blank.

After a dry spell you may find shrivelled specimens reduced to thin, horn-like, dark films glued to the bark. Wet them for an hour and they rehydrate to something close to their original shape, which is a useful confirmation when a specimen is too shrunken to read.

Taking A Spore Print

A spore print from a jelly fungus is fiddly but achievable and worth doing once. The problem is that the body slumps and its own water sheets across the paper. Work on glass or a glazed tile rather than card, and prop the specimen spines-down on two matchsticks so the teeth hang clear of the surface with a few millimetres of air below them. Cover with a glass or a box to hold humidity, leave it eight to twelve hours somewhere cool, then lift it off and tilt the glass against a dark background at a low angle.

The deposit is white, thin, and easily lost against a pale surface, which is why glass viewed over black works far better than white paper. Under a microscope the spores are broadly ellipsoid to almost spherical, roughly 5 to 7 micrometres, smooth and colourless. If you go further and squash a fragment of the spine surface, look for basidia divided lengthwise into four cells by vertical walls. That cruciately septate basidium places the fungus with the jelly fungi rather than with the true toothed fungi, and it is the character underpinning its modern classification.

Substrate And Season

Rotting conifer wood is the default: spruce and pine most often, fir and hemlock readily, with a scatter of records from well-rotted broadleaf wood in some regions. Standing dead stumps, fallen trunks, buried limbs and discarded sawn timber in damp shade all work, provided decay is advanced and the wood holds water. Fruiting peaks from late summer through autumn and continues into early winter in mild oceanic climates; in cool wet mountain forests specimens turn up through much of the year.

Separating It From Look-Alikes

Against Exidia species such as the black witches' butter, the difference is the fertile surface: Exidia is smooth to convoluted and studded with minute wart-like pegs that are papillae rather than spines, and its overall form is a shapeless blob or cushion rather than a stalked bracket. Against Tremella, the form is lobed and brain-like, often yellow or pale, again toothless. Against Auricularia, the body is ear-shaped and rather leathery, with a veined but spineless underside.

Against the terrestrial toothed fungi — Hydnum repandum and its relatives — everything differs except the presence of spines: those arise from soil, have opaque pale orange to buff caps, firm brittle flesh, and no translucency at all. Sarcodon and Hydnellum species are tough, corky or almost woody and often strongly zoned. Mucronella produces bare white spines directly on wood with no cap or stalk whatsoever, so there is nothing to turn over. Dacrymyces forms small orange gelatinous cushions with a smooth surface. Once you have handled a Jelly Tooth for thirty seconds — translucent, rubbery, spined below, laterally stalked, on conifer wood — none of these remain plausible.

A Compact Field Sequence

1. Wood is coniferous and softly rotted, in deep shade.
2. Body is translucent against the light and springs back when squeezed.
3. Upper surface matt and minutely velvety, grey to grey-brown or white.
4. Underside carries soft, flexible, translucent conical spines.
5. Stalk short, lateral to off-centre, of the same jelly material.
6. Cut surface uniform, no colour change, no latex.
7. Spore print white, best read on glass over a dark background.