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bird's nest fungus

bird's nest fungus (Crucibulum spp.)

Features and Behaviors

The body of a fungus (mycelium) is made up of strands called mycelia. The mycelium grows within the soil, a dead tree or other object and is rarely seen. The fruiting body that produces spores is generally present for only a short period of time but is the most familiar part of the fungus to people. The bird’s nest fungus has brown, thin, dry cups that contain white spore cases. Each spore case is attached to the cup by a tiny cord. Spores are produced in a spore case that is not capable of ejecting them. The outer surface of the cup is yellow-gray to brown-orange. The cup is about one-fourth to three-eighths inch tall and wide. The common name of this fungus was given because the spore cases in the cup resemble eggs in a bird’s nest.

The bird’s nest fungus may be found statewide in Illinois growing on dead plant material, such as fallen logs. The cups develop in clusters. Spores are produced in late summer and fall. The spores provide a means of reproduction, dispersal and survival in poor conditions. Spore production occurs when conditions are favorable, generally with warm temperatures and ample moisture. Unlike plants, fungi do not have roots, stems, leaves, flowers or seeds. The bird’s nest fungus must absorb nutrients and water from the objects it grows in.

Illinois Range


​Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Nidulariaceae

Illinois Status: common, native