Bonfire Scalycap Identification Guide

The Setting Does Half the Work

Very few fungi are so tightly bound to one situation. You find this one by finding old fire: the blackened circle where a campfire sat, a bonfire site in a garden or allotment, the charcoal-strewn ground left by a heath or forest burn, the ash and part-burnt wood around a charcoal clamp. In that context, standing on a crust of black soil where nothing much is growing yet, a scatter of small tawny mushrooms is already halfway identified before you crouch down.

The first impression is of a modest, warm-brown mushroom, 2 to 5 centimetres across, sitting low on a slim brownish stem, often in loose troops of a dozen or more with their caps at slightly different heights. In damp weather the caps have a faint shine, as though varnished with a thin syrup. Fingers coming away slightly tacky from the cap surface are a useful early confirmation.

Working Through the Cap

Begin with shape. Young caps are convex to almost hemispherical with the margin curved inward; with age they flatten out, sometimes with a very low broad umbo, and the margin may become slightly wavy or upturned in old, weathered specimens.

Colour is warm and unevenly distributed: date brown, tawny or foxy ochre over the centre, fading outwards to a paler ochre or dull yellowish buff at the margin. Wet caps look darker and more rufous, dried caps paler and more yellow, so record the weather along with the colour.

The surface is thinly viscid or tacky when moist, drying to a smooth matt or slightly shining skin. That tackiness is a genuine character rather than surface water: grass blades, needles and fine ash grains stick to the cap and stay stuck. Scattered over this, mainly near the margin, are small pale veil remnants, which may look like whitish flecks, tiny fibrillose scales or a fringe of tissue hanging from the cap edge. They wash off in heavy rain, so their absence on a battered specimen means little.

The Gills

The gills are attached to the stipe, adnate to slightly emarginate, sometimes with a very short tooth running a millimetre down the stem. They are moderately crowded and fairly narrow.

Colour progression is the most useful gill character. They start pale, a whitish cream or pale straw with a faint olive or yellowish cast, then move through clay brown to a distinctly rusty or cinnamon brown as the spores mature. The gill edges stay paler than the faces, often finely uneven, which is easiest to see with a lens against the light.

Note carefully what the gills are not: they are not free of the stipe, and they are not deeply decurrent. A young specimen should be split lengthwise with a thin blade to confirm the attachment before the cap opens out and blurs it.

Stipe, Veil and Base

The stipe is 2 to 5 centimetres tall and 3 to 6 millimetres thick, cylindrical or slightly widening at the base, and usually curved because it has to work its way up through uneven ash and charcoal. Its upper part is pale, buff to yellowish, and smooth; below the veil zone it is covered in small fibrillose scales and darkens progressively to rust brown or almost blackish brown towards the base.

There is no proper membranous skirt. Instead the partial veil leaves a fibrillose ring zone, a faint band of fibres part way up the stipe which usually becomes obvious only when it catches falling spores and turns rusty brown. Look for that dusted band; it is one of the more reliable confirmations of the genus in the field.

Excavate the base with a knife rather than pulling. You should find the stipe running down into the burnt crust, often with dark mycelial threads binding grains of charcoal into a small mass. There is no bulb, no volva and no rooting tap root.

Flesh and Colour Change

Section the fruit body from cap centre to stipe base. The flesh in the cap is thin, soft and pale yellowish; in the stipe it is firmer, more fibrous and browner, darkening downwards to match the exterior. There is no dramatic reaction to cutting. Handled or bruised areas may slowly go a duller brown, and old specimens water-log and darken all over, but no rapid red, blue or yellow change occurs. The smell is faintly earthy or slightly raw-mealy, and is not a decisive character.

The Spore Print

Cut the stipe flush and set the cap gill-side down on paper, half on white and half on black, under a cover to slow evaporation. Two to six hours is normally enough; overnight is more reliable for small caps.

The deposit is brown, in the clay brown to dull cinnamon range, occasionally with a slight rusty tinge in a thick smear. Judge it by scraping the deposit into a compact patch with a blade. That brown print, added to attached gills, a tacky cap and a fibrillose ring zone, places the fungus firmly in Pholiota and separates it from every white-spored and every dark-purple-spored fire fungus.

Substrate and Season

The substrate is the identification. This species is pyrophilous, fruiting on burnt soil, charcoal fragments, ash-enriched ground and partly charred woody debris. It is one of the classic early colonisers of a burn, following the heat-sterilised ground within months and often persisting for a couple of seasons until competing plants and fungi close over the site.

Fruiting is unusually long, from spring right through to late autumn wherever the ground is damp enough, which is another useful clue: a small tawny mushroom on charcoal in May is far more likely to be this species than most alternatives.

Sorting the Fire Fungi Apart

Several fungi share the burnt ground, and they separate cleanly on structure.

Myxomphalia maura is grey-brown, its cap is depressed at the centre, its gills are pale and clearly decurrent, and its spore print is white. The gill run-down alone settles it.

Tephrocybe anthracophila and its allies are dull grey-brown, dry-capped, with pale gills and a white spore print, and they lack any veil or ring zone.

Psathyrella pennata is much more fragile, with a dry, silky-fibrillose grey-brown cap that fades in bands as it dries, a brittle hollow whitish stipe, and a very dark purplish brown to blackish spore print.

Small Coprinellus species on burnt ground are thin-fleshed, pleated or grooved to the disc, and blacken or dissolve at the margin as they mature.

Geopyxis carbonaria and the other burn-site cup fungi are simply cups on short stalks, with no gills at all.

Within Pholiota, look-alikes are separated by habitat and stature: Pholiota lenta is larger and paler with a distinctly slimy whitish cap and grows in leaf litter, while the wood-inhabiting scalycaps such as Pholiota squarrosa are clustered on trunks and stumps and are conspicuously coarsely scaly on both cap and stipe.

A Compact Field Sequence

Confirm burnt substrate; check for a tacky tawny cap with pale veil flecks at the margin; confirm gills attached and turning rusty brown; find the fibrillose ring zone dusted rust; note the darkening scaly lower stipe; take a brown spore print. Six checks, and only one genus survives them.