Ghost Fungus

Ghost fungus grows in overlapping clusters on wood, with fan- to funnel-shaped caps that can reach about 30 centimetres across. A large cluster on a eucalypt stump is one of the more striking things in an Australian wood.

The color is variable and unhelpful. Caps run from cream through pale gray to smoky brown, often darker toward the center and paler at the margin, and the same cluster can show most of that range at once.

What does not vary is the gills.

They are crowded, pale, and decurrent, which means they run a long way down the stem instead of stopping where the cap ends.

That decurrent run is easy to see and easy to feel. Draw a finger down from the cap edge toward the base and the gill ridges continue under your fingertip well past the point where a cap-and-stem mushroom would have become smooth.

The flesh is thin in the cap and gets progressively tougher toward the base. By the time you reach the point of attachment it is closer to a piece of wood than to a mushroom, and that gradient is worth learning by hand.

Almost everything written about this mushroom leads with the glow, and in the field the glow is not available to you.

It needs full darkness and eyes that have had ten or fifteen minutes to adapt, it is strongest in fresh mature specimens and fades as they age, and a torch beam or a phone screen erases it completely. Nobody stands in a wood at night deciding whether to eat something.

So identify it the way you would if the glow did not exist, using only what daylight shows.

The stem is where the decision gets made, and it is a texture rather than a shape.

Take hold of the base and try to tear it the way you would tear a piece of oyster mushroom. Ghost fungus resists, splits along fibres, and feels stringy. An oyster mushroom gives way softly and tears cleanly.

Do that before anything goes in a basket rather than after, because once several clusters are mixed together you have lost the chance to test each one at its base.

Ghost fungus is a wood decomposer, and it works on living trees as well as dead ones.

It fruits in overlapping clusters at the base of trunks, on stumps, and from buried roots, which is why clusters sometimes appear to be growing out of bare ground with no wood in sight. Eucalypts are the usual host, which puts the species in the woodland and the suburb at once.

Street trees, park plantings and garden stumps produce it as reliably as bushland does.

That urban presence matters more than it sounds. A large share of the people who encounter this mushroom are not out foraging in a forest, they are looking at something that appeared overnight in a garden.

The season runs mainly through autumn and into early winter after rain, though a wet year can produce fruiting outside that window. Clusters can be large and persist for a couple of weeks, darkening and drying as they age.

There are no culinary notes for this mushroom, and the absence is the point.

Cooking does not make it safe. The illudins are not deactivated by ordinary kitchen heat, and reports of poisoning include meals that were thoroughly cooked before they were eaten.

Nor does the usual folk reasoning help. It is not bitter enough to warn you off, it does not look diseased, and a young specimen can be firm and pleasant to handle.

The only correct handling is to leave it where it is, or to collect one specimen for identification and keep it well away from anything intended for a kitchen.

The illudins have a genuine research history, which is not the same as the mushroom having a medicinal use.

Illudin compounds have been studied as starting points for anticancer chemistry because they are potently cytotoxic, and that cytotoxicity is precisely why the mushroom makes people ill. A compound being interesting to a laboratory is not a reason to eat the organism that produces it.

Nothing about ghost fungus supports any traditional or supplemental use, and there is no preparation of it that is safe to consume.

Nobody cultivates ghost fungus for food, and there is no reason to.

It has been grown in laboratories to study its bioluminescence, which is a research activity rather than a hobby one, and the practical interest for a grower is the opposite: making sure it is not what came up in a wood-chip bed intended for an edible species.

That does happen. Outdoor beds mulched with hardwood or eucalypt chips sit in exactly the habitat this fungus occupies, so anything appearing in a bed needs identifying rather than assuming.

This poisonous mushroom has no place in a meal.

Publishing a composition table for a mushroom nobody should eat would suggest a use that does not exist, and the only quantity worth stating is that no amount is a safe amount.

The old name explains the modern problem.

Ghost fungus was once placed in Pleurotus, the oyster mushroom genus, which is a fair record of how similar the two look to a careful observer. It now sits in Omphalotus, a genus whose members are consistently bioluminescent and consistently poisonous.

That genus is worth knowing by name because it repeats elsewhere. The jack-o-lantern mushrooms of North America and Europe are Omphalotus too, they glow the same way, and they are confused with chanterelles rather than with oyster mushrooms.

So the pattern generalises even though the lookalike does not. A glowing gilled mushroom growing in clusters on wood is an Omphalotus, and no member of that genus is food.