Crucibulum laeve - Common Bird's-nest Fungus

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes (Gasteromycetes)

Order: Agaricales

Picture courtesy of Michael and Hilary Rose

Crucibulum laeve is one of several species of bird's-nest fungi and is among the most common. That's not to say that any of the bird's-nest fungi are easy to find, as they are so tiny and easily overlooked.

This remarkable fungus grows on rotting wood and vegetation. Initially a yellow-brown, tapering cup-shaped fruitbody with a yellowish wooly membrane covering the top, once mature the embrane fall away revealing egg-like peridioles that contain the spores of the fungus. The 'eggs' are attached to the base of the nest by fine threads that break when raindrops knock the eggs from the nest. By this unusual means the spores are dispersed.

Identification Guide

Dimensions	Cup-shaped fruitbodies, each 'nest' containing typical five to eight whitish 'eggs' each typically 1.5mm in diameter. A 'nest' is typically 5 to 10mm across and up to 10mm tall.
Other features	Often in such densely-packed groups that nests become distorted by the pressure from neighbouring fruitbodies.
Stem	None.
Spores	White to creamy yellow.
Odour/taste	Not significant.
Habitat	Mainly found on fallen dead twigs, old rotting timber and decaying vegetation. Distribution seems to be very patchy.
Season	July to October.
Occurrence	Not often found because of their small size, but they may be quite common in places.
Similar species	Several similar species occur throughout Europe. Cyathus striatus (with ribbed nest walls) and Cyathus olla (often on manured soil) are also found occasionally in the British Isles, mainland Europe and further afield.