Cyathus olla - Field Bird's Nest

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes (Gasteromycetes)

Order: Agaricales

Cyathus olla is one of several species of bird's-nest fungi and is distinguished by its relatively large 'eggs' or peridioles as they are known in mycological circles. Although initially silvery, the eggs soon turn grey, giving the mature fruitbody a sombre appearance that is in stark contrast to its appearance when the 'lid' is on the nest. Although they occur on twigs and woodchip mulch, another good place to look for these tiny fungal fruitbodies is on dead marram grass stems on coastal sand dunes.

Identification Guide

	Description Funnel-shaped fruitbodies form initially as fluffy orange blobs on woody debris; they become darker with age, and the orange lid falls away to reveal the egg-like peridioles. Each peridium or 'nest' contains typical four or five silvery flattened 'eggs.' The outside of each peridium is covered with fine grey-brown hairs; the inner surface, in contrast, is smooth and hairless. Dimensions Peridia are 6 to 10mm across and up to 15mm tall, with noticeably flared rims. The individual peridioles are typically 3 to 3.5mm across.
	The silvery-white peridioles soon darken. Their attachment to the base of the nest-like cup is easily broken when raindrops hit them, and they are thrown out tiddlywinks style onto the ground, where they eventually split to release their spores.
Stem	The base of the cup tapers inwards to form a rudimentary stem.
Spores	Whitish.
Odour/taste	Not significant.
Habitat	Mainly found on fallen dead twigs, old rotting timber, manured soil, horse dung and decaying shrubby vegetation. In Britain this species can also be found on coastal dunes, where it is saprobic on dead marram grass stems.
Season	May to November.
Occurrence	Not often found because of their small size, but they may be quite common in some areas.
Similar species	Cyathus stercoreus is very similar (its rim is not so widely flared, however) but its peridioles are much smaller and sometimes as many as 20 are produced in one peridium; it is a dung-loving species (the specific epithet stercoreus means 'filth') but is also found on marram grass in coastal sand dunes. Several similar species occur throughout Europe. Cyathus striatus (with ribbed nest walls) and Crucibulum laeve are fairly common (but equally hard to spot) in Britain and Ireland as well as on mainland Europe and further afield.