Palamino Cup

The Palamino Cup is one of the larger and more frequently encountered members of Peziza, a genus of fleshy, brittle ascomycete cup fungi in the family Pezizaceae. Fruiting bodies begin as small closed or shallowly saucer-shaped discs and expand into broad, spreading cups whose margins eventually flatten, split and curl outward — the repanda of the scientific name refers to exactly this recurved, wavy edge.

What sets this species apart within an often confusing genus is the combination of a comparatively large size, a pale tan to warm brown inner surface, a whitish and minutely scurfy outer surface, and a strong preference for woody substrates rather than bare mineral soil. Mature specimens can look almost plate-like, sitting nearly flat against a decaying stump or a bed of landscaping chips.

Like all Peziza species it is an ascomycete: spores are produced in cylindrical sacs (asci) lining the upper, inner face of the cup. A ripe colony will sometimes release a visible puff of spores as a faint smoke when jarred or breathed upon, a behaviour shared by many operculate discomycetes.

Fruiting body

The cup is 3–12 cm across, at first shallowly bowl-shaped with an inrolled edge, soon expanding to a broad saucer and finally becoming irregularly flattened with a wavy, split, outward-recurved margin. Older specimens are often distorted where several fruit bodies crowd together.

Surfaces

The upper (inner, spore-bearing) surface is smooth, pale tan to medium brown or milk-coffee coloured, sometimes darkening with age. The outer surface is distinctly paler — whitish to very pale buff — and finely mealy or scurfy to the touch, without the coarse hairs seen in many other cup groups.

Stipe

Essentially absent. The cup is sessile or narrows to a short, blunt, rudimentary stalk-like point of attachment, usually anchored directly to wood or wood debris.

Flesh & spore print

The flesh is thin, whitish, brittle and snaps cleanly rather than tearing. There is no colour change of note when the tissue is broken and no milky exudate. The spore print is white; the spores themselves are smooth and elliptical, a useful microscopic separator from the warted-spored Peziza species.

Palamino Cup is a wood-associated species. It fruits on rotting hardwood stumps and logs, on buried wood, and very commonly on wood chips, bark mulch and sawdust piles — which makes it one of the more frequent cup fungi in gardens, parks and landscaped beds. It also appears on soil that is rich in woody debris, and occasionally at the base of standing dead trunks.

Fruiting runs from spring through autumn, peaking after sustained rain, and a single flush may produce dozens of cups in overlapping tiers. The species is widespread across temperate North America and Europe, and has spread readily with the modern use of shredded bark and chip mulch in cultivated ground.

This is a saprophytic fungus that decomposes lignin- and cellulose-rich plant material, taking no nutrients from living plants. Its mycelium threads through decaying hardwood and mulch, breaking the substrate down and returning carbon and mineral nutrients to the soil, which is why it is such an early coloniser of freshly spread wood chips.

The life cycle is that of a typical operculate ascomycete. Spores land on suitable damp woody material and germinate into mycelium; when conditions are right the mycelium forms compact knots of tissue that swell into closed spheres, then open into cups. The inner cup surface is a palisade of asci, each firing eight spores into the air through a small hinged lid at the tip.

Several Peziza species overlap in appearance. The Domicile Cup Fungus (Peziza domiciliana) is paler — whitish to pale buff rather than warm tan — and typically fruits on plaster, cement, sand and building debris rather than wood, and its cups tend to remain more bowl-like with a less dramatically recurved margin. The Cellar Cup (Peziza cerea) is smaller, more persistently cup-shaped with a thicker, waxy-looking pale ochre flesh, and also favours mortar, damp masonry and mineral debris.

The Common Brown Cup (Peziza phyllogena) is much darker, olive- to chocolate-brown on the inner surface, and grows on soil and humus rather than on wood. Peziza varia in the broad sense is extremely similar in the field and is separated chiefly on microscopic details of the spore-bearing layer. Any dark brown, ground-dwelling cup with a granular exterior and yellowing tissue is more likely one of the Peziza succosa group.