Pig's Ears Identification Guide

The First Impression

Spring in conifer forest, often in the mountains, sometimes within metres of the last patch of melting snow. You are walking past rotting spruce and fir logs, sawdust piles and old chip heaps, and half-buried in the needle duff are reddish-brown crumpled discs — the sort of thing your eye first registers as a wet fallen leaf or a curl of loose bark. Look again and the shape resolves: a shallow, wavy, chestnut-brown saucer sitting almost flat on the wood, its underside conspicuously paler. That contrast, dark above and pale beneath, is the first real clue to Gyromitra perlata.

The Overall Form

This is an ascomycete, so forget everything about caps and gills and read it as a cup fungus instead. Young fruit bodies are genuinely cup-shaped, 3–6 cm across, with an inrolled rim. They expand quickly into flattened saucers and then into irregular discs 5–10 cm and sometimes 15 cm across, with the margin becoming wavy, folded, lobed and finally contorted so that older specimens look crumpled rather than round.

Underneath, there is no proper stalk. Instead the disc sits on a short, thick, sterile boss that is strongly ribbed, and those ribs radiate outward from it onto the lower surface as raised veins. In deep litter the boss may be entirely buried, so lift the fruit body and brush the base clean before deciding whether a stalk is present.

The Fertile Surface

The upper, inner face is the hymenium — this is where the asci sit and where spores are discharged. It is reddish-brown, chestnut, date-brown or dark tan, occasionally with ochre tones, and it is matte and moist rather than shining. Young discs are fairly smooth; mature ones become distinctly wrinkled and veined, with a system of low ridges radiating from the centre and strongest there. On very old, heavily contorted specimens the surface can become almost brain-like in its folding, but it never inflates into the hollow, lobed head of the classic false morels.

The Sterile Surface

Turn the disc over. The outer face is strikingly paler: whitish, cream, pale buff, sometimes lightly ochre-tinted, and finely furfuraceous — that is, covered with a fine scurf or minute granular warts that you can just resolve with a lens. The ribs from the basal boss continue outward across this surface as pale raised veins. The colour contrast between the two faces is one of the easiest things to check and one of the most useful.

The Flesh

Cut a fruit body vertically through the middle. The flesh is thick for a cup fungus — commonly 2–5 mm — whitish or very pale cream, firm but brittle, and it snaps cleanly rather than tearing. In section you can often see a faint layering, with a denser zone beneath the fertile face. There is no colour change on exposure, no latex, and no staining when the surface is rubbed. The smell is mild and faintly earthy.

Reading the Spores

There is no spore print in the agaric sense, but there are two ways to sample spores. In the field, find a mature fruit body on a still, bright morning, breathe gently on the fertile surface or nudge it, and watch: a visible white puff rises as thousands of asci discharge together. Indoors, lay a fresh disc fertile side down on dark glass or dark paper overnight under a cover, and you will collect a whitish spore deposit.

Under the microscope the spores are the clincher. They are very large — roughly 25–35 × 8–12 µm — ellipsoid to fusiform, ornamented with warts or a coarse partial reticulum when fully mature, and, most importantly, drawn out at each end into a distinct pointed apiculus. They typically contain one large central oil droplet flanked by two smaller ones. Nothing in Peziza has those apiculate ends.

Substrate, Season and Ecology

Gyromitra perlata is a saprotroph of conifer wood. Look for it on decaying logs and stumps, on sawdust and chip piles, on buried wood, and on wood-rich duff in spruce, fir and pine forest; it is far less often reported from broadleaf debris. It is frequently gregarious, with a dozen or more discs scattered along a single rotting trunk, sometimes fused together where they crowd.

The season is early. This is one of the first substantial fungi of the year in montane conifer forest, fruiting from spring into early summer and following snowmelt upslope as the season advances, so a species that is finished at valley level may only just be starting a few hundred metres higher. Cool, damp, shaded northern aspects are the productive ground.

Separating It from the Look-Alikes

Peziza species (P. badia, P. repanda, P. vesiculosa and relatives) are the commonest confusion, because they are also brown cups. They stay more genuinely bowl-shaped, their inner surface is smooth rather than ribbed and veined, their flesh is thinner and more watery-brittle, and the outer surface lacks the strong radiating ribs. Their spores are smooth or finely warted and have no apiculi. Habitat differs too: soil, burnt ground, compost, dung and disturbed earth rather than conifer logs.

Disciotis venosa also fruits in spring and is strongly veined, but it grows on soil in damp broadleaf woods, riverbanks and old orchards; it is duller and greyer brown, larger and flatter, with a white-scurfy outer surface, and its spores are smooth and lack apiculi.

Gyromitra infula is saddle- to mitre-shaped, with two or three lobes raised on a distinct stalk, and it fruits in late summer and autumn, not spring.

Gyromitra montana and G. gigas are spring snowbank species too, but their fertile tissue is inflated into a convoluted, brain-like head on a stout, chambered, ribbed stalk; they are never flat discs.

Sarcosphaera coronaria develops underground as a hollow ball and then splits open into a crown of pointed rays, with a pale lilac inner surface.

Morchella species have a pitted and ridged hollow head fused to a hollow stalk; a vertical cut through a morel is hollow from top to bottom, which no Gyromitra perlata ever is.

A note on names: many books call this fungus Discina perlata or Discina ancilis, and Gyromitra ancilis is widely treated as the same taxon. If your reference uses one of those combinations, it is describing the fungus in your hand.

A Quick Field Sequence

Spring, conifer wood; cup expanding to a wavy, contorted disc; fertile face reddish- to date-brown, wrinkled and radially veined; outer face whitish and scurfy; short ribbed sterile boss instead of a stalk; thick brittle white flesh with no colour change; huge apiculate warted spores discharged in visible puffs.