Dung-loving Bird's-Nests

Appearance

The fruiting bodies, or perida, are funnel- or barrel-shaped, 6–15 mm tall, 4–8 mm wide at the mouth, sometimes short-stalked, golden brown to blackish brown in age. The outside wall of the peridium, the ectoperidium, is covered with tufts of fungal hyphae that resembles shaggy, untidy hair. However, in older specimens this outer layer of hair may be completely worn off. The internal wall of the cup, the endoperidium, is smooth and grey to bluish-black. The 'eggs' of the bird's nest – the peridioles – are blackish, 1–2 mm in diameter, and there are typically about 20 in the cup. 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. In 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. However, Brodie reports that sometimes "C. stercoreus" is found without a funiculus, which has led some authors to misidentify this species with the genus "Nidula".

The spores of "C. stercoreus" are roughly spherical and relatively large, with typical dimensions of 20–35 x 20–25 µm, although great variability in spore size has been noted. The spores are sessile, and are separated from the basidia after it collapses and gelatinizes. This is accompanied by the gelatinization of the inner walls of the peridiole.

Distribution

Being coprophilous, "C. stercoreus" grows on dung, in soil with dung, and bonfire sites; it has also been recorded growing on sand dunes. The fungus is known to have a worldwide distribution, and Curtis Gates Lloyd, in his monograph on the Nidulariaceae, wrote that it "probably occurs in every country where manure occurs".

Behavior

The life cycle of "Cyathus stercoreus", which contains both haploid and diploid stages, is typical of taxa in the basidiomycetes that can reproduce both asexually, or sexually. Basidiospores produced in the peridioles each contain a single haploid nucleus. After dispersal, the spores germinate and grow into homokaryotic hyphae, with a single nucleus in each compartment. When two homokaryotic hyphae of different mating compatibility groups fuse with one another, they form a dikaryotic mycelia in a process called plasmogamy. After a period of time and under the appropriate environmental conditions, fruiting bodies may be formed from the dikaryotic mycelia. These fruiting bodies produce peridioles containing the basidia upon which new basidiospores are made. Young basidia contain a pair of haploid sexually compatible nuclei which fuse, and the resulting diploid fusion nucleus undergoes meiosis to produce haploid basidiospores.

Habitat

Being coprophilous, "C. stercoreus" grows on dung, in soil with dung, and bonfire sites; it has also been recorded growing on sand dunes. The fungus is known to have a worldwide distribution, and Curtis Gates Lloyd, in his monograph on the Nidulariaceae, wrote that it "probably occurs in every country where manure occurs".

Cultural

"Cyathus stercoreus" has been investigated for its ability to break down lignin and cellulose in agricultural byproducts, like wheat straw or grasses. It selectively breaks down lignin, leaving much of the cellulose intact, which increases the amount of digestible carbohydrate for ruminant mammals, and enhances both its value as a food source and its biodegradability. The enzymes responsible, laccase and manganese peroxidase, also have industrial applications for lignin degradation and removal in the pulp and paper industry. Liquid cultures of "C. stercoreus" have also been shown to biodegrade the explosive compound 2,4,6-trinitrotoluene.