Earthfan Identification Guide

The First Impression and the Setting

The ground tells you as much as the fungus. Think sandy, acid, poor soil under conifers: a young pine plantation, a heath with scattered pines, dune slacks, the mossy sides of forest tracks, a sandy bank cut by a path, or a forest nursery bed. This is one of the most common fungi of exactly that habitat, and once you have your eye in you find it constantly.

What you see is low and dark: overlapping rosettes of thin brown fans lying almost flat against the soil, or leaning out from a bank like small brackets that have fallen over. Individual fans are 1 to 6 cm across, and colonies spread to 20 cm or more, sometimes coalescing into ragged mats. The colour is a dull sepia to reddish-brown, and the first reaction of most people is that they are looking at dead leaves, torn bark or a scrap of old fabric.

One habit gives it away at a distance: it grows up around whatever is in its path. Grass stems, heather twigs, pine needles and the bases of conifer seedlings are frequently encased in a brown fibrous collar, with the plant emerging out of the middle of the fungus. Very few soil fungi do this so conspicuously.

Reading the Fruitbody From Above

Pick out one fan and look at the upper, sterile face. The outline is fan-shaped to spatula-shaped, often deeply lobed and split, and usually several fans are stacked in overlapping tiers attached at a narrow point or a short stub at the back.

The surface is radially fibrous. Fine fibres run outwards from the attachment towards the edge, giving a streaked, combed or coarsely silky look, and towards the rim they frequently break up into a shaggy fringe. Colour is darkest at the centre - deep brown, reddish-brown, sepia, sometimes almost black - and grades outwards, and the actively growing margin is markedly paler, whitish, cream or pinkish-buff, and finely torn.

That pale ragged edge on a dark radially streaked fan is the single most useful visual signature. When growth stops, the pale margin darkens to match the rest, so late-season material can look uniformly brown.

The Spore-Bearing Surface

Lift a fan and look underneath. There are no gills, no tubes and no teeth. Instead the fertile face is a continuous surface that is uneven, warted, wrinkled and often radially ridged, in shades of purple-brown, greyish-brown or clay-brown, usually a little paler or greyer than the top.

Under a hand lens it looks granular and lumpy, as if the surface had been stippled. It is neither smooth and polished, like the underside of a crust fungus on wood, nor organised into any regular pattern. That disorganised warty fertile face is what places the specimen in this genus, and it is worth training your eye on it because it is the character most often overlooked.

Texture, Flesh and Colour Change

Handle the fungus. Fresh fans are tough, leathery and flexible: you can bend one double and it springs back rather than tearing. In dry weather they become stiff and brittle, and after rain they soften again, so the same colony changes character with the weather.

Cut a fan across with a blade. The flesh is very thin, under a millimetre, and fibrous, and it is brown all the way through, with no contrasting layers, no gelatinous zone and no distinct crust. There is no latex, no juice and no colour change on cutting or bruising. The smell is earthy or faintly musty, like damp soil or old leaves.

One practical test: try to tear a fan. It resists, then tears along the radial fibres in a stringy way. A dead leaf tears cleanly across; this does not.

Taking a Spore Print

This takes a little improvisation because the fertile surface faces downwards where the fungus grows. Detach a mature fan, set it fertile-side down on white paper, cover it and leave it overnight in a still place.

The deposit is purple-brown to a warm mid-brown, and it can be sparse. Under the microscope the spores are the clinching character for the family: pale purple-brown, distinctly angular to irregularly lobed in outline, and covered with blunt spines or warts, measuring roughly 8 to 12 micrometres including the ornament. Nothing else that looks like a small brown leathery fan on sand produces angular, spiny, brown spores, so a single lens view resolves any doubt.

Substrate, Partners and Season

This species is ectomycorrhizal, meaning it lives in partnership with tree roots. Pines are its principal partners, along with spruce and other conifers, and it associates with birch and oak as well. It is particularly associated with young trees, and it is a familiar sight in forest nurseries and recent plantings, where it can sheath the base of seedlings in brown fibrous collars.

It fruits on sandy and peaty soils, on mosses, in needle litter, on bare mineral soil of banks and track sides, and among heather. Fruiting runs from midsummer through late autumn, and dried fans persist into winter and revive after rain, so the colonies are visible for months.

The ecology explains the pattern you see on the ground. Fruitbodies often follow the run of a root or the line of a path, so look for streaks and arcs of brown fans rather than isolated individuals.

Separating It From the Look-alikes

Thelephora penicillata and Thelephora anthocephala. Same genus, same sort of ground. The difference is architecture: their fruitbodies are branched and divided into narrow finger-like or feathery tips, often whitish or pale at the very ends, giving a coral-like or plumed outline. Earthfan is made of broad plain overlapping fans, not fingers.

Thelephora caryophyllea. Also on sandy pine ground, but it forms a distinct funnel or vase shape with a definite central stalk, and its outline is more regular and more clearly zoned in concentric bands.

Coltricia perennis. The commonest genuine confusion, because it too forms tan-brown zoned rosettes on sandy track edges. Separate them underneath: Coltricia has a proper pore surface with small round to angular tubes, a well-defined central stalk, a neatly circular funnel-shaped cap and silky concentric bands on top. Earthfan has a warty non-poroid underside and no central stalk.

Hydnellum and Phellodon. Tough brown soil fungi with a similar leathery feel, but their underside carries obvious spines or teeth, their flesh is much thicker and often zoned in section, and many exude coloured droplets when fresh.

Stereum and other bracket-forming crusts. These are thin and leathery too, but the fertile underside is smooth, and they are always attached to wood - fallen branches, stumps, standing dead trunks - rather than growing out of sandy soil and moss.

Jelly fungi such as Auricularia. Rubbery and translucent, collapsing when squeezed, and again on wood.

Dead leaves and bark. Lift the object and flex it. A Thelephora fan is tough, fibrous and does not snap or tear cleanly, and its underside is warty rather than veined or smooth.

A Working Sequence

Note the sandy conifer ground. Look for the pale fringed margin on a dark radially fibrous fan. Turn one over and confirm a warty, unorganised brown fertile surface with no gills, pores or teeth. Test the leathery flex. Check whether the colony has grown around grass stems or seedling bases. Take a print for the purple-brown deposit and, if you can, look at the angular spiny spores.