What You Should Know
Peziza arvernensis is an inedible species of apothecial fungus belonging to the family Pezizaceae. This fungus appears as brown cups, often in small groups, on soil in broad-leaved woodland, especially with beech. The ascocarps can grow quite large, up to 10 cm (3+7⁄8 in) across. This species is widespread in Europe with a few records from North and South America.
The exterior of the fruit bodies is pale tan, while the interior is brown. Peziza vesiculosa and P. violacea are similar, young specimens of the latter having a violet hue.
Other names: Brown Cup Fungus, Fairy Tub, Woodland Cup.
Peziza arvernensis Mushroom Identification
Saprobic, growing alone or in clusters on the ground in hardwood and conifer forests, usually in areas that have accumulated woody debris; spring through fall - or in winter in coastal California; widely distributed in North America.
Cup-shaped when young, often flattening with age or becoming irregularly shaped due to the clustered growth habit; reaching a width of about 8 cm across; upper surface brown and fairly smooth, sometimes becoming slightly wrinkled; under surface minutely velvety with whitish fuzz, at least when young; without a stem; attached to the substrate at a central location. Odor none. Flesh is fragile and brittle.
Spores 15-20 x 9-10 µ; smooth when immature, sometimes becoming finely warted with maturity; elliptical; without oil droplets. Asci eight-spored; with blue tips in Melzer's Reagent; up to 235 x 15 µ. Paraphyses slender, with swollen tips.
Peziza arvernensis Look-Alikes
Found on old masonry, rotting textiles, and sandy soils. It forms a tan to ochre-brown cup, sometimes with pinkish to vinaceous tints, has smooth spores, and septate paraphyses.
Has a dark-brown hymenium with a dingy reddish-brown, pustulate, outer surface, remains cupulate at maturity, has roughened to sculptured spores with 1-2 oil droplets, and occurs on soil in woods.
Is an ochre-brown species distinctive for its urn shape at maturity and preference for fruiting on straw enriched with horse and cow dung.
Peziza arvernensis Taxonomy and Etymology
This cup fungus was described scientifically in 1879 by French mycologists Ernest Roze (1833 - 1900) and Jean Louis Emile Boudier, who called it Peziza arvernensis - the name by which it is still generally known today.
Peziza, the genus name, may come from a Latin root referring to a foot - most fungi in this group being sessile (footless or stemless). The specific epithet arvernensis refers to the Auvergne region of central-southern France.
Aleuria arvernensis (Roze & Boud.) Gillet
Peziza silvestris (Boud.) Sacc. & Traverso
Photo 1 - Author: Holger Krisp (Creative Commons Attribution 3.0 Unported)
Photo 2 - Author: Tatiana Bulyonkova (Creative Commons Attribution 4.0 International)
Photo 3 - Author: Riet van Oosten (Public Domain)