What You Should Know
Peziza domiciliana is an inedible species of fungus in the genus Peziza, family Pezizaceae. The fruiting body is a cup-shaped ascocarp, morphologically the same structure produced by the fungal symbiont (mycobiont) of lichens and many other fungi. Spores are produced in a microscopic sac-like structure called an ascus, a unique structure found in cup fungi, yeast, leaf-curl fungi, truffles, and many lichenized fungi called lichens. It is grown on rotten wood, drywall/plasterboard, and plaster in homes, damp cellars, and basements. It is known from Asia, Europe, North America, and Antarctica.
Information regarding the toxicity of Peziza domiciliana is currently not available but it is believed to be non-toxic. There are no reports of adverse health effects. Allergenicity has not been studied.
Other names: Carpet Cup, Cellar Cup, Home Cup, Domestic Cup Fungus, Domicile Cup Fungus.
Peziza domiciliana Mushroom Identification
Saprobic, growing alone or gregariously in indoor settings or outside in garages, concrete rubble, coal bins, sand, and so on; year-round; widely distributed in North America.
When young circular in outline and cup-shaped, sometimes with a tiny stem; in age flattening out to become irregularly saucer-shaped (but usually retaining a depressed center); 2-10 cm wide; upper surface at first whitish, darkening to yellowish-brown or pale brown, smooth or wrinkled; under surface paler brown or whitish, finely mealy; flesh pale, sometimes bruising slowly yellowish; odor not distinctive; often surrounded by whitish mycelium.
Habitat and Distribution
The fruit bodies of Peziza domiciliana grow singly, in groups, or clusters on plaster, sand, gravel, and coal-dust in cellars, caves, and greenhouses. The species is known from Europe, North America, and South America (Argentina). The fungus has been identified as one of several responsible for the degradation of construction wood used in historical monuments in Moldavia. It has also been recorded from Deception Island of Antarctica, and the eastern Himalayas. The fungus has been implicated in a case of hypersensitivity pneumonitis (called El Niño lung in the original report), in which a previously healthy woman developed severe dyspnea and was found to have restrictive lung disease and evidence of alveolitis.
Spores 11-15 x 6-10 µ; smooth or slightly roughened at maturity; without oil droplets or with 2 small droplets. Asci eight-spored; with blue tips in Melzer's Reagent; up to 250 x 12 µ. Paraphyses slender; septate; with slightly swollen tips.
Peziza domiciliana Look-Alikes
Is a lookalike species.
Similar in appearance to P. repanda and has often been mistaken for it.
Is darker brown, grows on the ground or well-decayed wood, and has longer spores measuring 15–19 by 7–10 μm.
Peziza varia and Peziza petersii
Are among other cup fungi that occasionally grow indoors (Arora).
Also occurs on damp walls, plaster, and mortar, (Hansen, K.).
Is close and has been regarded as a color form of Peziza domiciliana.
Peziza domiciliana How to Spot It
Although this fungus prefers alkaline conditions it can pretty much grow everywhere where there are constant moisture, nutrients, and a porous surface, so be sure will most likely find it in severely damp areas such as your bathroom or basement.
When young, the fungi will appear circular in outline and cup-shaped, sometimes with a tiny stem.
Brown, yellow or even whitish.
Odor not distinctive.
Peziza domiciliana How to Treat
As with dry rot and wet rot, your number one priority is to stop the source of moisture, however, as it is plaster fungus (non-wood rotting type) there is no need to implement a fungicidal spray. This is completely optional and should only be considered if damp timbers are left in situ.
With any fungus growth, it’s always wise to speak to a professional who can correctly identify and recommend methods of removal. This will ensure the problem area is eradicated and eliminated to prevent further regrowth.
Peziza domiciliana Taxonomy
The fungus was first described in 1877 by the British botanist Mordecai Cubitt Cooke, based on specimens sent to him that had been found growing on the walls, ceilings, and floors of a house in Edinburgh that had been partially destroyed by fire. The species was transferred to genus Aleuria by Ethel Irene McLennan & Halsey in 1936, and later into Galactinia by Irma J. Gamundi in 1960; both of the binomials resulting from these generic transfers are synonyms of P. domiciliana.
Photo 1 - Author: Britney (Riverdweller) (Creative Commons Attribution-Share Alike 3.0 Unported)