Orange Jelly

Orange Jelly (Dacrymyces chrysospermus) is the largest and most conspicuous member of its genus, producing vivid orange gelatinous masses on decaying conifer wood. Where its small relatives make millimetric spots, this species forms convoluted brain-like or petal-like clumps several centimetres across, often in long runs following the cracks of a decorticated log.

The most useful character is the base. Pick a fruiting body off the wood and turn it over: there is a distinct pale to white attachment point, sometimes described as a rooting stub, where the tissue grades from orange into whitish and grips the wood. No Tremella shows this, and it is the single quickest way to place an orange jelly in the Dacrymycetes.

Belonging to the Dacrymycetes, the species has tuning-fork basidia and causes brown rot, unlike the white-rot-associated or mycoparasitic jellies of the Auriculariales and Tremellomycetes. It is a common and welcome splash of colour on conifer slash and windthrow through the warmer half of the year.

Fruiting body

Gelatinous masses 1–6 cm across, made of crowded lobes and folds forming a brain-like, cushion-like or crumpled-petal shape. Frequently gregarious, with many masses in a row along a crack or a run of exposed heartwood, sometimes fusing into strips 20 cm or more long.

The white base

The diagnostic feature. Where the mass meets the wood there is a whitish to pale cream point of attachment, often visible without lifting the fungus if it is viewed from the side, and obvious as a pale stub when detached. The rest of the tissue is uniformly orange.

Colour and texture

Bright orange to deep orange-yellow when fresh and hydrated, becoming duller orange, then dark reddish-orange as it dries and finally shrinking to a hard dark crust. Texture firm-gelatinous and elastic, somewhat tougher than the Tremella jellies.

Flesh and spore print

Flesh uniformly gelatinous with no fibrous core and no ring, volva or stipe; no bruising colour change. Spore print pale yellowish to whitish.

Orange Jelly is strongly tied to conifer wood, especially logs, stumps and large branches that have lost their bark and reached a moderate stage of decay. Pine, spruce, fir, Douglas fir and hemlock are all frequent substrates, and it is common on forestry slash, windthrown trunks and old stacked timber in conifer plantations.

The fruiting season runs from late spring through summer to autumn, extending later in mild wet climates. The species is widespread across the conifer forests of North America and is recorded from Europe and Asia, being especially abundant in western North America.

Dacrymyces chrysospermus is a saprotroph causing brown rot in conifer wood. Its mycelium exploits cellulose in wood that has already lost its bark and begun to check and crack, leaving the residual timber brown, friable and blocky. The rooting whitish base marks the point where the fertile tissue connects to that internal mycelium.

As with the other Dacrymycetes, the fruiting body is engineered for intermittent water availability, swelling rapidly after rain and drying into a hard crust that survives long dry spells intact. This lets a colony fruit repeatedly across a whole season from the same points on a log, so a well-established trunk can be productive year after year.

Tremella mesenterica (Yellow Brain) is a clearer yellow, softer and more watery, lacks a whitish attachment point, and grows on attached hardwood branches while parasitising Peniophora crusts. Tremella aurantia (Golden Ear) is firmer and deeper orange but grows on hardwood alongside Stereum hirsutum and again has no pale rooting base.

Dacrymyces stillatus (Common Jellyspot) is the same colour but only a few millimetres across and broadly attached without a pale stub. Guepinia helvelloides (Apricot Jelly) is pinkish-salmon and forms funnel- or tongue-shaped structures arising from soil over buried wood rather than lobed masses on an exposed log.