fairy circle, fairy ring - a ring of fungi marking the periphery of the perennial underground growth of the mycelium

toroid - the doughnut-shaped object enclosed by a torus

Fungi, fungus kingdom, kingdom Fungi - the taxonomic kingdom of lower plants

plant part, plant structure - any part of a plant or fungus

partial veil, velum - membrane of the young sporophore of various mushrooms extending from the margin of the cap to the stem and is ruptured by growth; represented in mature mushroom by an annulus around the stem and sometimes a cortina on the margin of the cap