Syn. Meth. Fung.: 237. 1801.
Common Name: bird's nest fungus
Fruiting body at maturity 10-15 mm in height, up to 13 mm broad, the base narrow, tapering upward, flaring at the mouth; margin frequently wavy, occasionally slightly reflexed; when young the mouth covered with a cream to buff-brown membranous lid (epiphragm); peridium tough, pliant, the outer surface with appressed, fine, brownish-grey hairs, inner surface smooth, shiny, grey, not striate, but sometimes with faint concentric bands; peridioles, disc-shaped silvery-grey, enclosed in a translucent to whitish thin membrane (use hand-lense) and attached to the inner cup surface or to each other via a short, white cord (funiculus).
Spores 10-12 x 6.5-7.5 µm, elliptical, smooth, thin-walled; spores hyaline.
Scattered to clustered on soil, often near or on woody debris; fruiting throughout the mushroom season.
Unknown. Too tough and small to be of culinary value.
The nature of the peridium and peridioles are key to identifying Bird's Nest fungi. In the case of Cyathus olla, the outer peridium is covered with appressed, fine, brownish-grey, hairs, while the inner cup surface surface is smooth, silvery to lead-grey as are the relatively large peridioles. Two other Cyathus species occur in our area. They include Cyathus striatus, which is distinguished by a shaggy, outer peridium and strongly, plicate-striate inner cup surface, and Cyathus stercoreus which has a narrower, cone-shaped nest, also has a shaggy exterior, a smooth, dark, inner peridium, and black, not grey peridioles. Besides the typical form of Cyathus olla, we have also found var. anglicus which is larger, and has a sulcate cup margin, a feature which could cause confusion with Cyathus striatus, but the latter as noted above has a shaggier aspect, and a conspicuously striate-plicate inner cup surface.
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