Cyathus olla also known as the field bird's nest is a species of saprobic fungus in the genus Cyathus of the family Nidulariaceae. The fruit bodies resemble tiny bird's nests filled with "eggs" – 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, and asexually via spores. C. olla is a relatively common fungus, with a worldwide distribution. It is the subject of agricultural research to determine its potential as a means to accelerate the breakdown of crop residue, and reduce the population of plant pathogens. The specific epithet is derived from the Latin word olla, meaning "pot". Description Cyathus olla bears a resemblance to a miniature bird's nest containing eggs, hence the common name bird's nest fungi. The fruiting body, or peridium, is roughly funnel-shaped, 10–18 mm tall and 8–12 mm wide. It is greyish yellow or greyish brown to fawn-colored and covered with even, fine-textured hairs on the outside surface. The inner surface is silver grey and smooth, often with faint transverse ridges. Cyathus olla is thick-walled, and flared outwards at the rim; the rim is typically wavy in outline. The 'eggs', or peridioles, typically number 8 to 10 in the cup, and they are white or grey in color, with a diameter of 2–4 mm—conspicuously larger than other Cyathus species. They are covered with a thin membrane called a tunica. Peridioles are often attached to the fruiting body by a funiculus, a structure of hyphae that is differentiated into three regions: the basal piece, which attaches it to the inner wall of the peridium, the middle piece, and an upper sheath, called the purse, connected to the lower surface of the peridiole. Inside the purse and middle piece is a coiled thread of interwoven hyphae called the funicular cord, attached at one end to the peridiole and at the other end to an entangled mass of hyphae called the hapteron. C. olla has a wide purse with an upper portion not easily distinguishable from the lower part. The species is inedible. A different form of this species, Cyathus olla forma anglicus, originally reported from England by mycologist Curtis Gates Lloyd, has also been found in Oregon and Colorado in the US, Alberta