Earthfan

The Earthfan is the best-known member of Thelephora, the type genus of the family Thelephoraceae. Its fruitbodies are neither gilled nor pored: the spore-bearing surface is simply the lower or outer face of a leathery, fibrous fan, roughened with low warts and wrinkles.

It is one of the standard fungi of sandy, acidic ground — heaths, dune slacks, conifer plantations and forest tracks — where it forms rosettes and clusters of shaggy brown fans, often clasping grass stems, twigs and seedling stems as it grows around them. In tree nurseries it can wrap the base of young conifer seedlings almost completely.

Its distinctiveness comes from texture and colour rather than shape: a dry, fibrous, almost cloth-like surface with radiating fibrils, deep rust to chocolate brown darkening with age, and a persistent whitish to pale fawn fringed growing edge.

Fruiting body

Fans and brackets 2–6 cm across, individually thin and leathery, usually overlapping in tiers or arranged as a rosette 5–12 cm wide. Fruitbodies commonly arise from soil at the base of small trees and may curve up around stems, grass and litter, incorporating debris as they expand.

Upper surface

Dry and fibrous, covered in coarse radiating fibrils and often with small erect scales; deep rusty brown, cocoa to chocolate brown or almost blackish-brown at the centre. The extreme margin is conspicuously paler — whitish, cream or pale fawn — and torn or fringed into fine points.

Fertile surface

The underside is smooth to distinctly warty, granular or shallowly wrinkled, never with true gills or pores. It is paler than the upper side at first, pale grey-brown, becoming purplish- or vinaceous-brown at maturity.

Flesh and spore print

The flesh is thin, tough, flexible and fibrous, and the whole fruitbody is dry and does not bruise to a different colour. The spore print is purple-brown, matching the mature underside; spores are angular and warted.

Strongly associated with light, sandy, acidic soils: pine heaths, dune systems, conifer plantations, forest rides and the beds of forestry nurseries. It also occurs on peaty and gravelly ground and along disturbed woodland edges, frequently pushing up through moss and needle litter.

Its main partners are pines, but it also associates with spruce, fir, larch, birch, oak and eucalyptus, and it is one of the most widely distributed ectomycorrhizal fungi in the world, recorded across Europe, Asia, North America and, following forestry plantings, much of the southern hemisphere. Fruiting runs from summer into late autumn, and old fruitbodies persist in a blackened, weathered state through winter.

The Earthfan is ectomycorrhizal: its mycelium sheathes the fine root tips of host trees, exchanging water and mineral nutrients — particularly phosphorus and nitrogen — for sugars from the tree. It is a classic early-stage coloniser, quick to form mycorrhizas on young seedlings, which is why it is so abundant in nurseries and on recently planted or disturbed sandy ground.

Because it fruits directly from the soil around its host roots, the fans often appear in rings or arcs following the spread of the mycelium. Purple-brown spores released from the warty underside are dispersed by wind and rain-splash, and the tough fibrous fruitbody structure lets it persist far longer than a fleshy mushroom.

Thelephora penicillata is paler and much more finely divided, breaking up into narrow branches with whitish bristle-like tips rather than broad fans. The Stinking Earthfan (Thelephora palmata) is upright and coral-like with flattened, whitened branch tips and a strong odour. Thelephora caryophyllea forms neater, funnel- or vase-shaped, concentrically zoned fruitbodies with a smoother margin.

The Tiger's Eye (Coltricia perennis) grows in similar sandy places and is also brown and zoned, but it has a regular circular funnel-shaped cap on a central stem and a true pored underside. Stereum brackets are superficially similar fans but always grow directly on wood, have a smooth, hard, often brightly zoned upper surface and a smooth underside, and give a white spore print.