Bird’s nest fungi, also known as splash cup fungi, are one of the most fun fungi to discover. They are common worldwide growing on decaying wood, organic matter and bark mulch. These saprophytes are among the important organisms that break down organic matter and return essential nutrients to the soil. Members of the Nidulariaceae family in the phyum Basidiomyota, these fungi are relatives of the mushrooms, puffballs and shelf fungi. Within the family Nidulariaceae, there are five genera, all bird’s nest fungi. The genera are differentiated based on physical characteristics such as color and form and more recently on DNA analyses.

Bird's nest fungi growing in wood mulch. J. Allen photo.

Bird’s nest fungi growing in wood mulch. J. Allen photo.

They are all distinguished by the resemblance of the fruiting bodies or spore structures to miniature bird’s nests. Within a tiny (about ¼”) cup-like structure called a peridium there are tiny egg-like structures called peridioles and these contain spores. The spores are dispersed when raindrops splash the ‘eggs’ out of the ‘nest’, propelling them up to about four feet away. In some genera, the egg is sticky so it will attach to the substrate it lands on. In others, the egg has a cord which attaches it to the nest. When it is dislodged by rain, the cord remains attached and has a sticky end. If the sticky end becomes attached to a small twig or piece of organic matter, the cord will wrap itself around the object.

The little nest-like fruiting bodies are just a small part of the fungus. Before these can form, a single spore germinates in a suitable substrate and under favorable temperature and moisture conditions. From this spore, a thread-like hyphal strand begins to grow and as it takes up nutrients from the breakdown of organic matter a network of hyphae called mycelium forms. Once the fungal mycelium is well-established, fruiting bodies will develop, typically during moist weather from July through October.

Note: Bird’s nest fungi are not considered edible.

  1. Allen