Phylum: Basidiomycota. Class: Agaricomycetes. Order: Agaricales. Family: Marasmiaceae
Scotch Bonnets get their name from the shape of the cap. It has a little nipple-like bump in the middle and its overall shape looks like piece of headwear that was worn in Scotland a while back. The other common name ‘Fairy Ring Champignon’ comes from the fact that this is the mushroom that makes fairy rings in lawns. Champignon’ means basically ‘edible mushroom’. They can grow in clusters or in open ended arcs (incomplete circles) as well, so the rings are only a guide to identification, not a fixed characteristic.
Fairy rings are, traditionally, where Fairies dance. This dance is invisible to most humans and to cross the circle during a dance is happening, you will be compelled to join in! So for dignity’s sake, harvest from outside the circle.
Interestingly, the grass close to a Scotch Bonnet is greener than grass that is not so near. This is because of a hormone that the mushroom releases that makes the grass greener. Maybe this is an evolutionary adaptation to lure grazing animals that will then eat the grass and mushroom and distribute the spores that way? Maybe it’s a way to lure Scotsmen?
Scotch Bonnets can dry out completely and spring back to life when water it rains. That is caused by a sugar called trehalose, which prevents severe cell damage when the mushrooms become dried out. As the mushroom cells rehydrate, they eat the trehalose and this helps them return to normal and even start producing spores again! That sugar also has the benefit of making the mushroom taste sweet taste when cooked. It’s my favourite dried mushroom.
Scotch Bonnets usually occur early in the season. There are a few similar mushrooms that grow in similar conditions so make sure you check the ID guide below.
If you find a ring or partial ring of small brown mushrooms on your lawn or an oval or park, the likelihood is that they’re Scotch Bonnets but check for these details first –
For reference, they’re listed on page 123 of ‘A field guide to Australian Fungi’ by Bruce Fuhrer.