This petite mushroom is a nuisance to lawn owners: its mycelium browns the grass in arcs and rings. But it redeems itself by being a fine food. A homeowner can fight back by eating the mushrooms as they periodically appear. The rings formed by Marasmius oreades increase in diameter with time as the fungus seeks new food. Rings may grow to many feet across. A number of studies measuring distance and growth rate have estimated that rings of the M. oreades are probably centuries old and hundreds of feet across. The grass inside the ring recovers, but along the borders the damage continues. The French call it faux mousseron, or "mushroom scythe." The fairy-ring mushroom fruits abundantly during the warm months in the eastern United States, and all year in the west after rain or periodic watering.
The flat, dry, tan to brown Marasmius caps are little more than 1 inch in diameter. The centers are raised and dome shaped. The widely separated buff-colored gills throw off many white spores. The odor of these mushrooms is agreeable. When waterlogged and aged, however, they acquire a fetid and disagreeable smell. It only takes one or two of these to foul a batch of dried mushrooms. Sun-dried specimens found on the lawn are safe, but not as good as mature caps dried at home. (Remember: do not try to identify mushrooms without the help of an expert.
Remove the fibrous stems with scissors and discard. They are too tough to eat. Insects seldom attack these mushrooms. Clean the tops under water with your fingers.
The flavor and aroma of M. oreades are out of proportion to its size. Added fresh to soups, ragouts, and stews, it confers a definite, somewhat sweet taste. This sweet quality also enhances the taste of cookies. It is excellent sautéed in butter with onions. Surprise your friends and family with a subtle change in flavor by adding this tasty and fragrant mushroom to your favorite soup. The caps are quite firm and tolerate long cooking. To prepare for use where shorter cooking times are called for, simmer them beforehand for 15 minutes in water with butter and lemon juice.
This mushroom is often dried before use, although it is delicious fresh. The caps are thin and dry quickly. String them on a thread with a button on the bottom and hang in a warm place. One of the unique characteristics of M. oreades is its amazing ability to rapidly take up water to resume its original texture, appearance, and taste. You needn't soak it prior to adding it to such foods as soups or stews. Just drop it into your pot.
Fairy-Ring Mushroom Soup
Serves 4 as first course
ALTERNATE MUSHROOM: Candy Cap
Rice Pilaf with Fairy-Ring Mushroom
Serves 4 as a side dish