Fairy ring mushrooms in their habitat: grassland or garden lawns. Photo: ImageSelect.
The name says it all: the fairy ring mushroom often forms rings. That may well come in handy for the upcoming garden count.
Does the species have gills beneath the cap? Yes – are the gills dark? No – does the species have decurrent gills? No – does the species have a ring? No – is the cap bright yellow to red? No – is it a small mushroom with a central umbo? Yes? Then it is a fairy ring mushroom. That, at least, is what the identification key for the upcoming garden mushroom count of 10–12 October – the first edition of this survey – suggests. Spotting the fairy ring mushroom is an added bonus: the species has been named mushroom of the year 2025 by the Dutch Mycological Society (NMV).
Garden-count suitability
That honour falls to the fairy ring mushroom (Marasmius oreades) precisely because of how well suited it is to a garden count, according to the NMV. The mushroom thrives on grassland and is therefore also found on garden lawns. And there it stays, because it is remarkably resilient. In hot weather the fairy ring mushroom dries out completely, only to revive fully after rain. This phenomenon struck the Swedish mycologist Elias Magnus Fries as worthy of an entirely new genus: loosely translated from ancient Greek, Marasmius means withered.
The pale, reddish to beige-brown fruiting bodies are also well known for the fairy rings they frequently form. In English the species is called the fairy ring mushroom, and its scientific name refers to this too. The specific epithet oreades was derived by the English naturalist James Bolton from the ancient Greek word for mountain nymphs. Like witches and elves, these were said to dance in circles.
Spreading outwards
In reality, a fairy ring does not arise as the remnant of a dance, but from an outward-spreading mycelium. In the fairy ring mushroom, the mycelium produces hydrogen cyanide, which poisons and kills the grass on the outer edge of the ring. Inside the circle, extra nutrients are released, causing the grass to grow more vigorously. Garden owners are therefore far from always pleased with the fairy ring mushroom. On the bright side, such a ring does earn them a handsome score in the garden count – every fruiting body counts.