Cyathus striatus, commonly known as the Fluted Bird’s Nest, is a fascinating saprobic fungus recognized for its unique fruiting body that resembles a tiny bird’s nest filled with eggs. It typically grows on decaying wood, bark, or plant debris in damp, shaded environments such as forest floors or garden mulch. This species is particularly noted for its fluted, hairy exterior and the small, lens-shaped peridioles (“eggs”) inside, which contain the spores.

Fruiting body begins as a fluffy, light-brown inverted cone and matures into a vase-shaped structure. As it ages, the pale lid that initially covers the opening falls away, often collapsing inside the nest to reveal four or five silvery, egg-like structures called peridioles. The outer surface of the nest is shaggy to woolly, grayish-buff to dark brown, and covered in tufts of fine hairs. In contrast, the inner surface is smooth, shiny, and distinctly fluted, an identifying feature reflected in both the species’ common name and its Latin epithet striatus. The peridioles, up to 2 mm wide, are ellipsoid to roughly triangular, sheathed, and attached to the nest by tiny cords known as funiculi. Spore print white.

Microscopic Features: Spores measure 15–20 x 8–12 µm and are ellipsoid in shape. They are smooth, have thick walls, and feature a distinct notch.

Cyathus striatus on the www.first-nature.com web site.
Cyathus striatus on the MushroomExpert.Com Web site.