A small toadstool, Coprinus disseminatus (family Psathyrellaceae), with a grey-brown, grooved, thimble-shaped cap, found growing in large clusters on rotten wood or in soil.
Origin
1970s.
Definition of fairies' bonnet in US English:
fairies' bonnet
noun
A small toadstool, Coprinus disseminatus (family Psathyrellaceae), with a grey-brown, grooved, thimble-shaped cap, found growing in large clusters on rotten wood or in soil.