Marasmius oreades

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Marasmius oreades
2010-10-16 Marasmius oreades (Bolton) Fr 112276.jpg
M. oreades the "fairy ring" mushroom.
Scientific classification
M. oreades
Binomial name
Marasmius oreades
(Bolton) Fr (1836)
Marasmius oreades
View the Mycomorphbox template that generates the following list
Mycological characteristics
gills on hymenium
cap is convex or umbonate
hymenium is adnate
stipe is bare
spore print is white
ecology is saprotrophic
edibility: choice

Marasmius oreades, the Scotch bonnet, is also known as the fairy ring mushroom or fairy ring champignon. The latter names tend to cause some confusion, as many other mushrooms grow in fairy rings (such as the edible Agaricus campestris, the poisonous Chlorophyllum molybdites, and many others).

Distribution and habitat[edit]

Marasmius oreades grows extensively throughout North America and Europe in the summer and autumn (fall) (June - November in the UK), or year-round in warmer climates. It loves grassy areas such as lawns, meadows, and even dunes in coastal areas.


Marasmius oreades grows gregariously in troops, arcs, or rings (type II, which causes the grass to grow and become greener). The cap is 1–5 cm across; bell-shaped with a somewhat inrolled margin at first, becoming broadly convex with an even or uplifted margin, but usually retaining a slight central bump- an "umbo"; dry; smooth; pale tan or buff, occasionally white, or reddish tan; usually changing color markedly as it dries out; the margin sometimes faintly lined.[1]

The bare, pallid stem grows up to about 7 cm by 5mm in diameter.

The gills are attached to the stem or free from it,[1] fairly distant (rather a distinctive character), and white or pale tan, dropping a white spore-print. The spores, themselves, are 7-10 x 4-6 µ; smooth; elliptical; inamyloid. Cystidia absent. Pileipellis without broom cells.[1]

This mushroom can be mistaken for the toxic Clitocybe rivulosa which lacks an umbo, is white to grey in color, and has closely spaced decurrent gills.


A dried string of 50 fairy ring caps.

Many mushroom connoisseurs are fond of M. oreades[1] and its sweet taste lends it to baked goods such as cookies. It is also used in foods such as soups, stews, etc. Traditionally, the stems (which tend to be fibrous and unappetizing) are cut off and the caps are threaded and dried in strings. A possible reason why this mushroom is so sweet-tasting is due to the presence of trehalose, a type of sugar that allows M. oreades to resist death by desiccation.[2] When exposed to water after being completely dried out, the trehalose is digested as the cells completely revive, causing cellular processes, including the creation of new spores, to begin again.

Ecological uses[edit]

Marasmius oreades can be used for the biological remediation of bismuth in polluted soils.[3]


  1. ^ a b c d Marasmius oreades (
  2. ^ Marasmius oreades, the fairy ring mushroom, leprechaun. Tom Volk's Fungus of the Month for March 2003
  3. ^ ^ Carmen Cristina Elekes; Gabriela busuioc. "The Mycoremediation of Metals Polluted Soils Using Wild Growing Species of Mushrooms". Engineering Education.

External links[edit]