Wrinkled Crust

Wrinkled Crust is one of the most photogenic resupinate fungi of autumn woodland. Fresh patches are a warm salmon-orange, sometimes flushed purple or violet, and have a soft waxy-gelatinous feel. What sets the species apart is the sculpture of the fertile surface: the older central area is raised into concentric warts and ridges that radiate outwards like the spokes of a wheel, while the outer zone remains smooth and paler.

The genus Phlebia belongs to the Meruliaceae and includes several crusts with folded or vein-like fertile surfaces intermediate between smooth and poroid. Phlebia radiata is the classic representative, and the epithet radiata refers directly to that radial wrinkling.

Colonies are usually on the upper or side surfaces of fallen logs and often reach the size of a hand. On drying, the whole crust becomes hard, dull and much darker, losing most of the orange.

Fruiting body

Resupinate, forming rounded to irregular patches typically 3–10 cm across, several often merging. Thickness is one to two millimetres, noticeably more substantial than a Peniophora.

Surface

The centre bears a raised network of radiating folds, ridges and blunt warts; the outer band is smooth and flatter. Colour is salmon-pink, orange or apricot, frequently with violet or purplish tones, and dries dull ochre-brown.

Margin

Whitish to pale pink, thin, finely fibrillose or fringed, and clearly demarcated from the coloured fertile zone.

Flesh and spore print

Flesh is soft, waxy to slightly gelatinous when fresh, becoming hard and horny when dried. No colour change on cutting. The spore print is white.

Grows on dead broadleaved wood — fallen logs, standing dead stems, large branches and cut stumps. Birch is a favourite, but it is also common on beech, alder, willow, ash and hazel, and is occasionally found on conifer wood.

Fruiting is concentrated in autumn and early winter, with the brightest specimens appearing after sustained damp weather; old dried crusts may persist much longer. The species is widespread across Europe and the north temperate zone generally.

Phlebia radiata is a saprotroph that causes a white rot, degrading lignin efficiently and leaving the residual wood pale, soft and fibrous. It is one of the more studied white-rot fungi because of the vigour of its lignin-degrading enzyme systems.

It typically colonises wood in the middle stages of decay, following the early pioneers, and can spread over large areas of a fallen trunk. Fruiting occurs directly on the wood surface when humidity is high; the raised radial folds increase the fertile area available for spore production.

Phlebia tremellosa is the nearest relative and shares gelatinous texture and orange-pink colour, but it forms a distinctly netted, merulioid surface and turns out a narrow reflexed bracket with a white hairy upper side. Phlebia rufa is duller buff to reddish and its folds form a coarse irregular network rather than clean radiating spokes.

Peniophora incarnata can be a similar coral colour but is much thinner and quite smooth, without any central wrinkling. Byssomerulius corium is whitish-cream and netted, lacking the warm orange tones entirely.