Wrinkled Peach Identification Guide

The Encounter

Most people find this species by accident while examining a big fallen hardwood trunk in damp autumn woodland. It grows low and often sideways, from the shaded flank or the underside of a decaying log, so it is easy to walk past and impossible to forget once seen. The colour arrives first: a warm apricot to salmon pink, glowing against dark wet bark. Then the texture registers, because the cap does not look like a normal mushroom cap at all. It looks like it has been moulded from tinted rubber and then embossed with a raised network of pale veins, as though a web of cords lay just beneath a translucent skin.

Reading the Cap

Caps are small to medium, roughly two to six centimetres across, occasionally larger on well-fed logs. Young ones are convex to almost kidney-shaped with a strongly inrolled margin that stays inrolled far longer than in most gilled fungi. The surface layer is a thickened, gelatinised pellicle: press it and it yields elastically, peel at the edge and it lifts as a rubbery skin rather than tearing into fibres.

The network is the character to read carefully. In humid conditions the pale ridges stand proud and interconnect across the whole cap in an irregular mesh, with the deeper apricot ground colour showing in the pits between them. In dry weather the ridges flatten, the mesh becomes a faint tracery and the whole cap pales towards buff-pink, so a dry specimen needs more careful work. Young fruit bodies in still, humid air frequently exude droplets of orange-red liquid from the cap surface and the stem, which stand as small beads and later dry to darker spots.

Gills, Stem and Base

Underneath, the gills are pink from the outset, deepening slightly with age, moderately spaced, fairly thick and soft, and attached to the stem with a shallow notch. Look along them with a lens: they are often connected by low cross-veins near the cap edge, echoing the mesh above. Nothing about them is decurrent in the way an oyster mushroom's gills run down the stem.

The stem is short, one and a half to three centimetres, and rarely central. It is usually clearly off-centre and often lateral and curved, because the fruit body grows sideways out of a vertical log face and then bends upward to bring the gills into a vertical hanging position. It is pinkish white to pale flesh colour, finely fibrillose, solid and tough. At the base there is no volva, no bulb and no ring, just a slightly felty pad of mycelium gripping the wood.

Flesh and Colour Change

Cut a fruit body vertically. The flesh is pinkish to pale salmon, distinctly rubbery and elastic rather than crumbly, and it is thickest under the disc. The gelatinised cap layer shows in section as a translucent band. There is no dramatic colour change on cutting, no latex and no blueing, although the exuded droplets on young caps can leave rusty red stains on adjacent tissue and on your fingers. A rubbery pink section under an embossed apricot cap is confirmation in itself.

Taking a Spore Print

Because the stem is off-centre and the cap is often produced sideways, lay the whole fruit body on its side with the gills over the paper rather than trying to stand it upright. Use white paper, cover it, and give it three to six hours in still air. The print is pale pink to salmon pink, and you may need to scrape it into a heap with a blade to judge the tint against white. A pink print immediately eliminates the oyster mushrooms and the whole white-spored bracket group.

If you can use a microscope, the spores are the clincher: almost spherical, and covered in coarse warts, quite unlike the smooth spores of the pink-spored genera you might otherwise consider.

Substrate, Season and Ecology

The substrate is the strongest habitat clue in the whole guide. This is above all a fungus of dead elm, fruiting on fallen trunks and large branches, on standing dead stems and around wounds, although it is also recorded on lime, ash, maple, beech and horse chestnut. It is a saprotroph that rots the wood from within, and it appears once decay is well established but the log is still firm and still holding moisture.

It wants damp, shaded, sheltered conditions and fruits mainly in autumn, sometimes lingering into early winter in mild spells. It usually appears singly, in twos and threes, or in small overlapping groups on one favoured section of a log while the rest of the trunk stays bare. Its fortunes have followed the elms: the great volume of dead elm created by disease produced a wave of suitable logs, and as that resource decays away the fungus becomes harder to find, which is why records often cluster around old elm hedgerows and river-valley woodland.

Separating the Look-alikes

Oyster mushrooms, Pleurotus ostreatus and relatives, share the log and the lateral habit. They have smooth, unnetworked caps in grey, brown or fawn, gills that run distinctly down onto the stem base, and a white to pale lilac spore print. Even the pink oyster, with its salmon colouring, lacks any raised network, lacks a gelatinised rubbery pellicle and prints whitish to pale lilac.

The olive oysterling, Sarcomyxa serotina, is another sideways log fungus, but it is olive-green to yellow-brown with a viscid cap, yellow gills and a white print. Panus conchatus is lilac-tinged, tough and hairy, with decurrent gills and a white print.

The genera that do share a pink print are Pluteus and Entoloma. Pluteus species have central stems, free gills and smooth, unsculptured caps, and while many grow on wood, none has the embossed rubbery surface. Entoloma species are overwhelmingly ground-dwelling with attached gills and angular spores. Crepidotus is small, stemless and prints brown.

In practice, no other fungus in temperate woodland combines an apricot-pink gelatinous cap, a raised interconnecting network of ridges, pink gills, an eccentric stem and a pink spore print.

Field Checklist

• On dead hardwood, overwhelmingly elm, in damp shaded woodland
• Cap apricot to salmon pink with a raised network of pale ridges
• Cap surface rubbery and gelatinised, peels as an elastic skin
• Margin strongly inrolled when young; orange-red droplets on humid young caps
• Gills pink, notched, often cross-veined; stem short and off-centre to lateral
• Flesh pink and elastic; spore print pale pink; spores round and warted
• Autumn into early winter, single or in small groups