Marasmius oreades, also known as Fairy Ring Marasmius, is a small agaric which is producing characteristic rings in lawns. It has a bell-shaped to convex cap, which becomes flatter with a broad umbo with age.
at first convex, then flat to cup-shaped with a low central hump that is often a darker shade. Colour varies from light beige to brown yellow. The margins are usually crinkled and almost transparent and streaky in damp weather. They turn lighter in dry weather and regain their colour in more humid conditions. The flesh is whitish buff, thick at the center, otherwise thin. Gills
free, sparse, and convex in the center with horizontal ridges. Creamy white at first, becoming ochraceous cream, fairly broad and distant. Spores
tall, coloured as the cap, smooth or finely scurfy, slender, more or less equal, whitish downy at the base and slightly rooting, stiff. The mushroom has no ring.
The poisonous Clitocybe dealbata is found in the same grassy habitat. It is distinguished by its decurrent gills. Can also be mixed up with the very poisonous mushrooms Clitocybe rivulosa and Clitocybe dealbata.
on the First Nature Web site.
on the MushroomExpert.Com Web site.