Purple Jellydisc

Purple Jellydisc is a gelatinous ascomycete that appears in dense clusters on dead hardwood, typically as a mass of irregular, brain-like or top-shaped lobes in a striking reddish-purple to wine colour. The species leads a double life: much of what is found is the asexual (conidial) stage, which forms shapeless gelatinous cushions, while the sexual stage produces tidier, shallow disc- or cup-shaped apothecia among them, usually later in the season.

Ascocoryne sits in the Helotiales alongside Neobulgaria and Bulgaria, a set of genera characterised by tough, gelatinised flesh, dark or bright pigments, and a preference for freshly dead broadleaf wood.

The colour is what makes it memorable — a fully wetted colony can look almost amethyst against pale beech wood, and it is one of the few genuinely purple fungi of the northern autumn.

Fruiting body

Two forms occur, often side by side. The conidial state consists of irregular gelatinous lumps, lobes and brain-like convolutions 5–15 mm across, sometimes fusing into a spreading mass several centimetres wide. The sexual state forms more regular shallow cups or top-shaped discs 5–15 mm across, tapering to a short thick base, with a smooth, slightly concave to flat upper surface.

Colour and surface

Both forms are reddish-purple, wine-purple or purplish-pink, sometimes with a paler pinkish-grey outer surface. The colours are strongest when the fungus is wet; in dry weather it shrinks to a dark, hard, almost blackish crust that swells and recovers its colour after rain.

Flesh and spore print

The flesh is gelatinous but firm and rubbery, translucent purple, elastic under pressure and not brittle. There is no colour change when cut. Spores are colourless, elliptical to spindle-shaped and often become septate; a spore deposit is white. Fruiting bodies almost always occur in crowded clusters rather than singly.

It fruits on dead hardwood — beech above all, but also oak, birch, ash, hornbeam, sycamore and willow — favouring cut stump surfaces, the ends of felled logs and large fallen limbs, often where the wood is already dampened and partly decayed. Conifers are used occasionally. The fungus prefers wood in relatively fresh to moderate stages of decay with the surface still intact.

The main season is autumn into early winter, with the gelatinous colonies persisting through frost and reviving repeatedly after rain, so colonies can be found into the new year. It is common and widespread across temperate Europe, North America and Asia, particularly in mature beech woodland.

Ascocoryne sarcoides is saprotrophic, causing a soft rot in the outer wood of dead broadleaves. It is an efficient early coloniser of exposed cut surfaces, which is why fresh stumps in managed woodland are so often covered in it within a year or two of felling.

Its life cycle is notable for the prominence of the asexual stage: gelatinous conidial cushions produce enormous numbers of conidia that spread the fungus locally, while the sexual apothecia, forming later in the same colony, produce ascospores for wider dispersal. The gelatinised tissue allows the colony to dry to a hard crust and rehydrate many times over a long fruiting season.

Ascocoryne cylichnium is virtually identical in the field, differing mainly in larger, more strongly septate spores and a tendency to form more regularly cup-shaped, slightly larger apothecia later in the year; reliable separation requires microscopy. Neobulgaria pura grows on similar beech wood but is pale pinkish-buff to translucent whitish rather than purple, and forms firmer, more regular top-shaped buttons.

Bulgaria inquinans shares the rubbery texture and clustered habit on oak but has a flat glossy black disc over a rough brown base. Tremella foliacea and purple-brown Exidia species are true jelly fungi, forming leafy or lobed translucent masses without the flat fertile disc, and Exidia surfaces are often minutely pimpled.