Stinking Earthfan

The Stinking Earthfan is an erect, branched member of Thelephora in the family Thelephoraceae. Although it looks like a coral fungus, it is not related to the true corals (Ramaria, Clavulina); its branches are leathery and fibrous rather than brittle, and it carries the purple-brown spores typical of its family.

It grows straight from soil, usually in conifer woodland, as a tuft of repeatedly forking branches rising from a short common base. The branch tips are the giveaway: instead of tapering to points they widen into flattened, fan- or spatula-shaped ends that are conspicuously paler, whitish or grey, against the dark body of the fruitbody.

The species is also famous for a strong, persistent and distinctly unpleasant odour, often likened to old cabbage or fermenting garlic, which lingers on the hands and on paper and can be detected from some distance in still weather.

Fruiting body

Erect tufts 3–8 cm tall and up to about 8 cm wide, arising from a short, tough stem-like base and dividing repeatedly into flattened, strap-like branches. Texture is tough, leathery and fibrous throughout; the fruitbody flexes rather than snapping.

Branches and tips

Branches are purple-brown, chocolate, grey-brown or nearly blackish, often with a violet cast when fresh and moist. Each ends in a broadened, flattened, fringed or toothed tip that is markedly paler — white, cream or ash-grey — giving the whole cluster a frosted appearance.

Fertile surface

Spores are produced over the outer faces of the branches, which are smooth to slightly wrinkled or minutely granular. There are no gills, pores or spines anywhere on the fruitbody.

Flesh, odour and spore print

The flesh is thin, fibrous and concolorous with the surface. The odour is strong, sharp and long-lasting. The spore print is purple-brown, and the spores are angular and warted like those of other Thelephora species. There is no distinct colour change when the branches are broken.

It fruits from soil, moss and needle litter in coniferous and mixed woodland, favouring the edges of forest tracks, mossy banks, and thin acidic soils where the litter layer is shallow. Fruitbodies appear singly, in small groups or in loose rings, sometimes half-buried in moss.

Spruce and pine are the usual associates, with fir and larch also recorded, and it occasionally occurs under broadleaf trees in mixed stands. It is widespread but rarely abundant across temperate and boreal Europe, Asia and North America, fruiting from late summer through to late autumn and blackening as it weathers.

Like the Earthfan, Thelephora palmata is ectomycorrhizal, forming sheaths around the fine root tips of conifers and supplying the tree with water and mineral nutrients in exchange for photosynthetic sugars. Its preference for thin, poor, acidic soils reflects the value of that partnership where nutrients are scarce.

Fruitbodies push up through litter directly above the mycorrhizal network, which is why they often follow the line of a root or the edge of a path where soil is compacted and thin. The tough fibrous construction allows a fruitbody to stand for many weeks, releasing purple-brown spores gradually rather than in a short flush.

True coral fungi are the main confusion. Ramaria species are fleshier and more brittle, usually ochre, yellow, tan or pinkish rather than purple-brown, with pointed or blunt tips that are not flattened into pale fans, and their spore prints are yellow to ochre. Clavulina species are white to grey, smooth and brittle with a white spore print.

The Earthfan (Thelephora terrestris) shares the colour and fibrous texture but forms flat, spreading fans and rosettes hugging the ground rather than an upright branched tuft. Thelephora penicillata is smaller, paler and forms low mats of fine branches with bristle-like white tips instead of broad flattened fans, and it lacks the strong odour.