Common Jellyspot Identification Guide

The Encounter

This one is found by looking down and looking close. A rain-soaked winter walk, a pile of sawn conifer logs, a weathered fence rail, the cut end of a stacked post — and along every crack and split in the wood, a line of small bright orange blobs, each no bigger than a match head, glistening as though someone had flicked wet paint into the grain.

That linear arrangement is the first thing to register. Common Jellyspot colonises the interior of wet dead wood and pushes its fruitbodies out wherever the wood has opened, so it emerges from checks, splits, saw kerfs and the seams between growth rings. The result is beads strung along a line rather than scattered randomly across a surface, and once you have seen it you will notice it on almost every damp piece of dead timber you pass for the rest of the winter.

Because the fruitbodies are 1 to 5 mm across, a hand lens is not optional. Take one, and if possible take a specimen home on a chip of its wood so you can watch it dry and rehydrate.

Reading the Fruitbody

Each fruitbody starts as a tiny gelatinous cushion, roughly circular in outline, attached directly to the wood by a broad base with no stalk. Young ones are neat little discs or pustules, slightly domed. As they mature they swell into irregular pads, become lobed or brain-like on top, and neighbouring ones fuse together into a chain or a wandering ridge several centimetres long.

Size per unit is small, generally 1 to 5 mm and rarely to 10 mm, but a fused colony can look far larger. The outline is never funnel-shaped, never cup-shaped, never branched, and never has a distinct stalk or a narrow point of attachment.

Reading the Texture

Touch one. Fresh, wet material is soft, gelatinous and slippery, and it deforms under a fingertip then springs back — the texture of a soft jelly rather than the rubbery firmness of the ear fungi or the wet felt of a slime mould. Squash one between finger and thumb and it smears rather than crumbling or powdering.

Then watch what happens when it dries. This is one of the most useful characters in the whole group. On drying the fruitbody shrinks dramatically, darkens to a hard reddish-brown, brown-black or almost black scab, and glues itself to the wood as a thin varnish-like crust that is easy to walk past unnoticed. Re-wet the same piece of wood and within an hour or two the crust rehydrates, swells, brightens and returns to a soft orange blob. If your specimen does this, you are firmly in the jelly fungi and firmly away from the slime moulds, which turn into dry powdery spore masses and never revive.

Reading the Colour

Colour runs from pale amber and egg-yellow through bright orange to a deep orange-brown, and it darkens with age and with drying. Young colonies are the brightest, and the freshest material can be almost translucent, so you can see the wood grain faintly through it when the light is behind.

There is no colour change on cutting or bruising, no latex, and no staining of the fingers beyond a faint smear.

The Spore-Bearing Surface

There are no gills, no pores and no teeth. In the jelly fungi the fertile surface, the hymenium, is simply spread over the exposed upper and outer face of the blob. That means every part of the visible surface is doing the work of a gill, which is why the fruitbody has no need of a stalk, a cap or an underside.

With a lens you may see that the surface of a mature fruitbody has a very slightly matt, faintly waxy sheen compared with the glossier lower part, and older colonies often develop a fine wrinkling as the surface expands.

Taking a Spore Print

A print is entirely possible despite the size, and it is worth doing once so you know what the group produces. Set a chip of wood carrying several fresh, plump fruitbodies upside down over a glass slide or a scrap of dark card, resting the wood on two matchsticks so the fruitbodies hang about 5 mm above the surface, and cover the whole arrangement with an upturned glass to hold humidity. Leave it overnight in a cool place.

The deposit is whitish to very pale yellowish and will be faint — expect a thin pale bloom rather than a solid layer. Read it against dark card.

If you have a microscope, the payoff is large. The spores are sausage-shaped, colourless, and become divided by cross-walls into several cells as they mature. More importantly, the spore-bearing cells are the diagnostic feature of the whole order: each basidium is deeply forked into two long arms, so under the lens it looks like a tuning fork. Nothing in the Tremella or Exidia groups shows that. If you ever want certainty about a jelly fungus, that tuning-fork basidium is the character to find.

Substrate and Season

Common Jellyspot is a decomposer of dead wood, and it is markedly fond of conifer timber: pine and spruce logs, sawn stumps, fence posts, rails, decking, garden furniture, stacked firewood and old planks. It also occurs on hardwood. Bark-free, weathered, water-holding wood suits it best, and it is especially abundant on worked timber left outdoors, which makes it one of the commonest fungi in gardens and on farms.

It fruits year-round wherever conditions are wet, but it is at its most obvious from autumn through winter and into early spring, when rain keeps the wood saturated for weeks at a time. Warm dry spells simply drive it back into its dark crust phase; the colony does not die, it waits.

Sorting Out the Look-alikes

Small Stagshorn (Calocera cornea) grows on the same wood in the same season and is the same orange-yellow, but its fruitbodies are upright cylindrical spikes or awls, 3 to 15 mm tall, tapering to a point, and they are noticeably tougher and more elastic than jellyspot. Shape settles it: spikes versus blobs.

Yellow Stagshorn (Calocera viscosa) is much larger and repeatedly branched into antler-like forks, growing from buried conifer roots and stumps, with a tough, sticky, almost cartilaginous texture.

Orange Jelly Spot (Dacrymyces chrysospermus) is the big relative, reaching several centimetres across, with a strongly lobed brain-like body and a distinct whitish attachment point where it grips the wood. It is essentially always on conifer wood with the bark off. Size and the white base separate it.

Yellow Brain (Tremella mesenterica) is brighter golden-yellow, far larger, and folded into deep convoluted brain-like lobes. It grows on hardwood branches, especially fallen gorse, hazel and oak, where it parasitises another crust fungus rather than rotting the wood directly.

Dacrymyces capitatus is very close but has a short, narrowed stalk-like base, so each fruitbody sits on a tiny stem rather than being broadly attached.

Lemon Disco (Bisporella citrina) forms dense sheets of tiny bright lemon-yellow discs on bare hardwood, but each disc is flat with a defined rim and a very short stalk, and the texture is soft and waxy rather than gelatinous. It also never revives from a dried crust.

Slime moulds such as Trichia and Fuligo can produce orange or yellow blobs on damp wood, but their texture is pasty and they mature into dry masses that release clouds of powder when touched, then never rehydrate.

A Field Sequence

Confirm the substrate is dead, damp wood, preferably worked conifer; note the beads running along cracks; confirm each unit is a small, broadly attached, unstalked, unbranched gelatinous blob; check the orange colour and the smooth undifferentiated fertile surface; squeeze one to confirm the jelly texture; and, best of all, watch a piece dry to a black scab and revive on wetting. That last test is the most satisfying confirmation available in fungal fieldwork.