Scientific Name: Nidulariaceae
Common Name(s): Bird’s Nest Fungi

Splash Cup Bird’s Nest Fungi ©Matej Frančeškin and ©Mushroom User

White Egg Bird’s Nest Fungi ©Grzegorz “Spike” Rendchen

Identification:

Bird’s nest fungi are often nestled on top of mulch or decaying wood. The mushrooms of these fungi, or their fruiting bodies, resemble a tiny bird’s nest with eggs in their mature form. The small egg-like structures are the mushroom’s spore containing capsules. In the immature form, the ‘nest’ enclosed in a globe-like protective covering called a peridium, which may have hair-like structures on its outer surface. As the fungus matures, the upper surface of the globe disintegrates, becoming a cup, to reveal the egg-like spore capsules. The spores are dispersed when water splashes into these cups, throwing them up to a meter away. The cups, which decompose slowly, are sometimes found attached to the underside of leaves long after the spores have been ejected.

All bird’s nest mushrooms are in the family Nidulariaceae, which includes at least 8 genera and many species that are found worldwide. There are many types of bird’s nest fungi with the general ‘cup and eggs’ form, with variations in the size, shape, color, and texture of both cup and eggs. Bird’s nest fungi are found throughout the United States. The two most common species in the southeast are ‘splash cup’ (Cyathus striatus) and ‘white-egg’ (Crucibulum leave).

Splash cup fungi are 6-10mm tall and 6-8 mm wide with a black and brown woolly surface. The cup top disintegrates over time, revealing grey, disc-shaped spore capsules. Cups grow more concentrated and closely grouped, with fruiting most common between midsummer and fall.

White-egg fungi are a little larger, with an outer cylinder 5-10 mm tall and 10 mm wide that disintegrates over time to reveal white, flattened spore capsules inside and cream with brown to orange brushing on the outside. Cups grow scattered, with more space in between, with fruiting most common between spring and fall.

 

Ecology:

Bird’s nest fungi are saprophytic, meaning they decompose organic matter and absorb the nutrients released. Bird’s nest fungi help decompose dead wood and mulch. They thrive in damp and shady areas. They often appear after a rain event has left the ground saturated with water. These fungi are gregarious, meaning they grow in groups but are not joined together.

The lifecycle of bird’s nest fungi is similar to most other mushrooms. Male and female spores grow hyphae, small thread-like root structures. When two hyphae of opposite genders meet, they fuse and grow a large hyphal net known as a mycelium. Given appropriate conditions, the mycelium produce a fruiting body, also known as a mushroom, which produces spores, starting the cycle over. Most species of mushroom fruit when moisture is high and temperatures are moderate. Bird’s nest fungi have a gastroid fruiting body, in which the peridioles, the spore containing capsules, develop within a peridium, a globe or ball with hair-like structures. This fungal globe is closed during the immature stage of the mushroom when the spores are developing. Once spores have matured, the larger membrane housing the spores splits along its circumference or disintegrates, exposing the spore capsules, which marks the beginning of the mature stage of the mushroom. During this stage, the mushroom resembles an open bowl with small circular spore capsules inside. The spores are dispersed when water splashes into these bowls, throwing spore capsules up to a meter away.

Bird’s Nest mushrooms and other fungi are vital to all ecosystems, as they facilitate decomposition and nutrient recycling. As mentioned, they are saprophytic and release enzymes into dead or decaying material, helping speed up decomposition. This helps the fungi mycelium and fruiting body directly by providing them with nutrients, while also benefiting the surrounding ecosystem. This organic breakdown of raw materials into more palatable forms benefits organisms that rely on soil nutrients to survive, such as soil invertebrates and plants.

 

Special Notes:

Here in Bella Vista, bird’s nest fungi are very common both in mulch beds and among decaying trees in forested areas. The two most common bird’s nest species in the southeast are ‘splash cup’ (Cyathus striatus) and ‘white-egg’ (Crucibulum leave).