Fairy Ring Champignon

Marasmius oreades (Bolton) Fr.

1 Observations

2 weeks ago Last Observed

The Fairy Ring Champignon (Marasmius oreades) is a small, buff to pinkish-buff mushroom with a low, domed cap and a central bump. The cap margin is grooved, the broad gills are well spaced, and the tough, pliant stem bends without snapping. It smells of bitter almonds, and the spore print is white.

It is common throughout the UK on open grassland such as lawns, meadows, parks and roadsides, and often forms large rings or arcs. Fruiting runs from May to Nov. It can survive drying out and revive when rain returns.

An edible species, but fairy rings are made by many fungi, so the ring alone proves nothing. Clitocybe rivulosa and Clitocybe dealbata also grow in grass rings and are poisonous. They have flat to funnel-shaped caps with no bump, and stiffer stems. Agrocybe praecox has buff gills that darken, and a brown spore print. Check every feature, and do not eat any Clitocybe.

Spore Print

Season

Native

non-toxic

Distribution

Common everywhere

Habitat

In open meadows, lawns, parks and roadsides, often in large fairy rings

Etymology

Marasmius comes from the Greek marasmos, meaning a withering or drying out. It refers to the way these fungi shrivel in dry weather and then recover when wetted, a trait Fries used to separate the genus from Collybia. The epithet oreades is from the Greek Oreads, the nymphs of mountains and valleys, a poetic link to the fairy rings the species forms in grassland.

Cap

The cap is hygrophanous, darker and tan-toned when wet, then fading to pale buff as it dries, usually keeping a darker centre. Young caps are bell-shaped to convex and flatten with age, keeping a low central bump. The margin is finely grooved over the gills when moist. The surface is smooth and dry.

Colour
Width	1.5 - 5 cm

Gills

The gills are thick and broad, with a waxy look, and are well spaced rather than crowded. They stay buff and are firmly attached to the stem.

Colour
Spacing	subdistant

Flesh

The flesh is firm and cream, thin in the cap but resilient, and it feels leathery rather than soft or brittle.

Colour
Odour	Bitter almonds
Taste	Pleasant, nutty

Stem

The stem is tough and fibrous, and it can be bent with a finger without snapping. It is slender, smooth and pliant, which helps to separate this species from the brittle-stemmed lookalikes.

Colour
Height	4.5 - 7.5 cm
Width	2.5 - 6 mm

Spores

Spores are smooth and ellipsoid to almond-shaped (pip-shaped). They are inamyloid, so they do not stain in Melzer's reagent. They produce a white spore print.

Colour
Type	inamyloid
Size	8-10.5 x 4-6 μm

Microscopic Features

Cystidia are reported as absent in the one source found (MushroomExpert). The cap surface is a hymeniform layer of clavate, pear-shaped or cylindrical cells, colourless to yellowish.

Confirmed

Unconfirmed