T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Cyathus olla (Field Bird's Nest)

Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Nidulariaceae
Genus: Cyathus
Species: C. olla
Binomial name: Cyathus olla
Synonyms: Peziza olla
Common name: Field Bird's Nest, Gray bird's nest.

Cyathus olla is a relatively common saprobic fungus with a worldwide distribution. The fruit bodies resemble tiny bird's nests filled with "eggs". They are spore-containing structures called peridioles. Like other bird's nest fungi, C. olla relies on the force of falling water to dislodge peridioles from fruiting bodies to eject and disperse their spores. The life cycle of this fungus allows it to reproduce both sexually, with meiosis (a type of cell division), and asexually via spores.

Cyathus olla obtains nutrients from the breakdown of dead organic matter, and as such is usually found growing on woody debris. Some specimens are found scattered to clustered on soil, growing on soil are they usually attached to bits of wood or stems present in the soil.

The funnel-shaped fruiting bodies (peridium) form initially as fluffy, circular, orange blobs. When young the peridium’s mouth is covered with a cream to a buff-brown membranous lid (epiphragm). These small peridium become darker with age, and the epiphragm covering the peridium falls away revealing the peridioles (eggs).
The fruiting bodies are roughly funnel-shaped, 10–18 mm tall and 8–12 mm wide. It is thick-walled, and flared outwards at the rim; the rim is typically wavy in outline
The inner surface can be bald and shiny or a silvery grey to a blackish colour, often with faint transverse ridges. 
The peridium outside surface is brownish, finely hairy or textured. It becomes smooth and grey with age.
The 'eggs', or peridioles, typically number 8 to 10 in the cup, and they are initially a silver-white but quickly darken in colour., with a diameter of 2–4 mm. They are covered with a thin membrane called a tunica. 

A nest of fungi

The adult funnel-shaped, fruiting bodies.

The young the peridium.

Photo of spores visible in a peridium and of a young peridium.still with its membranous lid (epiphragm).

Photo of a peridium that edge flared outwards and internal transverse ridges. 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/