Violet Fairy Cup

The Violet Fairy Cup is one of the classic pyrophilous — fire-loving — fungi, appearing in numbers on the blackened ground of old campfires, burnt brush piles and areas cleared by wildfire. Its small violet to purplish-lilac cups stand out vividly against charcoal, and a good flush can carpet a fire scar with dozens or hundreds of fruiting bodies.

It is a Peziza in the family Pezizaceae, and it shares the genus's brittle flesh, smooth inner spore surface and near-absence of a stalk. The violet pigment is strongest in young specimens and fades with age towards lilac-brown or dull greyish brown, so an old colony can be much less striking than a fresh one.

Several closely related violet burn-site cups exist and are separated chiefly by spore ornamentation, making Peziza violacea as usually reported a species that field workers treat as part of a small complex rather than a single tidy entity.

Fruiting body

Cups are small, usually 1–3 cm across and rarely more than 4 cm, at first almost closed and cushion-like, then opening into a shallow bowl or nearly flat disc with a thin, often slightly wavy margin.

Surfaces

The inner surface is smooth and violet, purplish or lilac when fresh, fading to lilac-brown or dull brown in age. The outer surface is paler and duller — greyish, brownish or pale lilac — with a fine mealy texture rather than hairs.

Stipe

Absent or reduced to a very short narrowed base, often gripping charcoal fragments or fine ash.

Flesh & spore print

The flesh is very thin, brittle, pale lilac to whitish, with no exudate and no colour change when cut. The spore print is white. The spores are elliptical and smooth in the strict sense of the species, which is the main separator from the warted-spored violet burn cups of the Peziza praetervisa group.

This species is essentially restricted to burnt ground. It appears on the charcoal, ash and heat-altered soil of old campfire rings, burnt stump holes, brush-pile burn scars, charcoal kilns and post-wildfire ground, usually some weeks to a couple of seasons after the fire itself. It will also fruit on soil enriched with scattered charcoal.

Fruiting runs from spring to autumn wherever moisture is available, and in mild regions it can appear in winter. It is widespread in temperate North America and Europe, and because fire sites are patchy and short-lived, colonies tend to be locally abundant but geographically scattered.

The Violet Fairy Cup is a saprophyte and a pyrophilous specialist. Heat sterilises the soil surface and removes competing mycelia, while the ash and charcoal alter pH and release mineral nutrients; species such as this one are adapted to exploit that brief window of open, alkaline, competitor-free substrate. Their spores are thought to persist in soil for long periods and to be stimulated by heating.

Colonisation of a burn typically follows a sequence, with small ascomycete cups among the earliest fungal fruiters, later giving way to other pyrophilous species. Spores are shot from asci on the inner cup surface into the open air above a bare fire scar — an unusually exposed, wind-swept microhabitat that suits this dispersal method well.

Peziza praetervisa is the most similar species, sharing burnt ground and violet colouring but generally growing slightly larger and having warted rather than smooth spores. Peziza subviolacea and Peziza echinospora also occupy fire sites; the latter is browner with spiny spores. Field separation within this group is unreliable without a microscope.

Away from the microscope, the useful contrast is with non-burn cups: the Common Brown Cup (Peziza phyllogena) and Yellow-juice Cup (Peziza succosa) are brown rather than violet and grow on unburnt woodland soil, the latter yellowing when cut. Small purple jelly-like discs on wood are more likely Ascocoryne species, which have a rubbery-gelatinous rather than brittle texture.