Marasmius oreades

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

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

Description
It 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 often retaining a slight central bump; dry; smooth; pale tan or buff, occasionally white, or reddish tan; usually changing color markedly as it dries out; the margin sometimes faintly lined.

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

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

Edibility
Many mushroom connoisseurs are fond of M. oreades and its sweet taste lends it to baked goods that mushrooms generally shy away from such as cookies. Traditionally, the stems (which tend to be fibrous and unappetizing) are cut off and the caps are threaded and dried in strings.The reason why this mushroom is so sweet-tasting is due to the presence of trehalose, a type of sugar that allows M. oreades to cheat death. When exposed to water after being completely dried out, the trehalose is digested as its cells completely revive, picking back up cellular reproduction and the creation of new spores.