Crimped Gill Identification Guide

First Impressions and the Setting

Plicaturopsis crispa, the Crimped Gill, is a species you notice by quantity rather than by size. Late in the year, typically from October onwards and often persisting through frosty spells into winter, you walk into damp deciduous woodland and find a fallen beech branch, a dead standing hazel stem or a suspended birch limb that appears to have been upholstered. Hundreds of small tan brackets, each only one to three centimetres across, are ranged along the whole length of the branch in overlapping tiers and rosettes, sometimes running in an unbroken band for a metre or more. Individually they are unremarkable; collectively they are one of the most striking sights of a late-autumn wood. The first impression is of warm ochre and tan tones with a distinct pale cream rim to every bracket, and of a soft, slightly rubbery texture that yields under a fingertip. Look up as well as down, because a great deal of the best material sits on attached dead branches a couple of metres above head height.

Reading the Cap

Each bracket is 1 to 3 centimetres wide, occasionally up to 4, and only a millimetre or two thick. The shape is fan-shaped, kidney-shaped or shell-like, attached to the wood laterally either directly by a narrow point or by a very short rudimentary stem-like extension. The margin is thin, strongly wavy, lobed and often inrolled when dry. Feel the upper surface: it is finely velvety or downy to the touch, not smooth and not sticky, and under a lens the fine tomentum is obvious. The colouring is concentrically zoned in bands of ochre-yellow, tan, orange-brown and cinnamon, usually darker towards the point of attachment and grading to a broad pale cream to almost white outer band at the growing edge. That pale rim on a zoned velvety cap is one of the two anchor characters.

Reading the Spore-Bearing Surface

The other anchor is underneath, and it is worth using a hand lens because the naked eye undersells it. The fertile surface is not made of true gills and it is not porous. Instead it consists of narrow, crowded, strongly crimped and crisped folds that radiate from the attachment point, forking repeatedly and joining one another in places to make a shallow anastomosing network. The folds look creased and wrinkled, as though the surface had been pleated and then partly relaxed, which is exactly what the English name records. They are blunt-edged and low, never deep, thin and knife-edged like the true gills of an agaric. Colour is pale cream to whitish when young, becoming ochre-buff or faintly pinkish-buff in age, and it stays noticeably paler than the upper surface. In dry weather the folds contract and the whole bracket curls up and hardens, and after rain it swells and revives, which is why the same colony can look quite different on two visits.

Flesh and Texture

There is very little flesh to examine, but its behaviour is informative. When moist, a bracket is soft, pliable and slightly gelatinous or rubbery, and it can be bent right back on itself without breaking. Tear one across and you see a thin, whitish, waxy-looking layer with no distinct separate layers or gelatinous core visible to the naked eye. When dry the whole thing becomes stiff, brittle, papery and shrunken, and the colours intensify. There is no colour change on bruising, no latex, and the smell is faint and unremarkable. This reviving habit is characteristic and lets the species survive weeks of alternating wet and dry weather on an exposed branch.

Taking a Spore Print

Getting a print from a bracket a centimetre across takes a little care but is entirely feasible. Cut a small block of the branch bearing several fresh, fully expanded brackets, or slice individual brackets off cleanly at the attachment. Arrange them fold-side down over black paper, propped on slivers of card or matchsticks so that the fertile surface is a few millimetres clear of the sheet and air can circulate. Enclose everything in a plastic box with a piece of damp tissue in one corner to keep the humidity up, and leave it in a cool, still place overnight. The deposit is white and rather sparse, best seen by tilting the black paper into the light. Under the microscope the spores are diagnostic for the group: very small, only about 3 to 4.5 by 1 to 1.5 micrometres, narrowly sausage-shaped, and they stain blue-grey in Melzer reagent.

Substrate and Season

This is a saprotrophic wood decayer, working on the bark and outer wood of dead attached branches and recently fallen twigs and limbs of broadleaved trees. Beech is the classic host, with birch, hazel, alder, hornbeam and various other broadleaves also used regularly. It shows a strong preference for branches that are dead but still relatively firm and still carrying bark, rather than heavily rotted or soil-contacted wood, and it is far more frequent on wood that stays off the ground. Fruiting is concentrated in autumn, mainly from October to December, and revived brackets often persist and continue to release spores through mild spells in winter. It is a northern and montane species in much of its range and has been expanding in many regions.

Separating the Closest Look-alikes

Plicatura nivea is the closest relative and shares the crimped folded underside. It is whiter overall, with a much paler and less strongly zoned upper surface, and it is most often found on alder and birch in cooler northern woodland.

Stereum hirsutum forms similar small tan zoned brackets on dead broadleaf wood, but its underside is completely smooth and even, with no folds at all, and it is coloured bright yellow-orange when fresh. Its texture is leathery and tough rather than pliable and reviving.

Chondrostereum purpureum also has a smooth underside, coloured lilac to purplish-brown, and a whitish hairy upper surface.

Schizophyllum commune has an underside of longitudinally split gill-like folds, each one grooved down the middle, and is greyish-white and coarsely hairy above rather than tan and velvety.

Trametes and Trichaptum species produce true pores or an irregularly poroid to toothed surface, quite different from smooth crimped folds, and Trichaptum species carry violet tints.

Crepidotus species are soft, whitish and fleshy with true, thin, sharp-edged radiating gills and a brown spore print.

Panellus stipticus has genuine crowded gills, a dry buff scurfy cap and a distinct short lateral stem, and grows mostly on oak stumps.

Phlebia and Merulius species can show crimped and folded surfaces but grow resupinate, spread flat over the wood surface, and are usually bright orange or violaceous.

Field Checklist

• Hundreds of small brackets in tiers along a dead broadleaf branch
• Fan or kidney-shaped, 1 to 3 centimetres, thin and pliable
• Velvety, concentrically zoned ochre to tan cap with a broad pale cream margin
• Underside of crowded, crimped, forking pale folds, never true gills or pores
• Rubbery when wet, hard and shrunken when dry, reviving after rain
• White spore print, tiny sausage-shaped spores
• Beech, birch, hazel and alder branches, October into winter