Rosy Conk

Fomitopsis cajanderi is a modest but memorable member of the brown-rot Fomitopsidaceae. The brackets rarely exceed a hand's width and are often overlooked from above, since the upper surface weathers to an unremarkable grey or blackish crust. Turn one over, however, and the pore layer is a clean rose to salmon pink, one of the few genuinely pink pore surfaces among temperate polypores.

Unusually for a polypore, the pink pigment is not confined to the surface: the context beneath is pink to pinkish-buff as well, so a cut through the bracket shows colour throughout. That character makes the species easy to confirm even on old, faded specimens whose pore surface has dulled toward brown.

It is a species of conifer forest across western and northern North America, where it fruits abundantly on stumps and downed logs, often in tight overlapping rows. It also readily colonises seasoned structural timber, making it one of the polypores encountered on bridges, poles and outbuildings as well as in the forest.

Cap

Brackets are 2–10 cm wide and 1–3 cm thick, semicircular to elongated, and often fused laterally into shelves or tiers along a log. The upper surface is finely velvety at first, becoming smooth, bare and crusted with age; colour shifts from pinkish-brown when young to grey-brown and eventually dark brown or blackish, sometimes with faint concentric zoning. The margin is thin, often paler and pinkish while actively growing.

Pores

The pore surface is the diagnostic feature: rose pink to salmon or deep pinkish-brown, fading toward tan in very old specimens. Pores are small and round to slightly angular, about 4–6 per millimetre, and darken where bruised. Perennial specimens show several stacked tube layers, all pink-tinted in section.

Stipe

Absent; brackets are sessile and broadly attached, frequently forming resupinate patches with turned-up bracket edges where the wood surface lies flat.

Flesh & spore print

The context is pink to pinkish-buff, tough and corky, and retains its colour when cut and dried — a reliable confirmation when the pore surface has faded. The spore deposit is white. Fresh brackets are pliable at the margin but the bulk of the tissue is firm and woody.

Rosy Conk fruits on dead conifer wood: Douglas-fir, spruce, true firs, pines, hemlock and larch, occurring on stumps, downed logs, slash piles and standing snags. It is also frequent on seasoned structural timber in outdoor settings, where it can appear on beams, posts and decking. Occasional collections come from hardwoods such as birch and alder.

The species is centred on western and northern North America — from Alaska and British Columbia south through the Rocky Mountains and Pacific states — and extends across boreal Canada, with related collections reported from northern Asia. As a perennial it can be found in every month, though new pink growth margins are most conspicuous through the warmer part of the year.

Like its close relatives, this fungus is a brown-rot decomposer. It digests cellulose and hemicellulose while leaving lignin behind, so the decayed conifer wood becomes reddish-brown, shrinks, and fractures into small cubes that crumble easily. The rot is typically concentrated in the sapwood and heartwood of dead trunks and stumps.

Ecologically it is a saprotroph, following the fungi that colonise wood immediately after tree death and continuing the breakdown for years. The cubical brown residue it leaves is slow to decompose further and becomes a long-lived component of forest soil organic matter. In cutover and burnt stands it is among the most abundant polypores on stump surfaces, and its brackets shelter mites, beetles and springtails.

Fomitopsis rosea is the closest relative and also has a pink pore surface, but its brackets are typically thicker, more strongly hoof-shaped, with smaller pores and a more northern, higher-elevation distribution on spruce. Careful comparison of pore size and bracket profile is usually needed to separate them.

Trichaptum abietinum also produces purplish to lilac-tinted undersides on conifer logs, but its fruiting bodies are thin, flexible, fan-shaped and annual, with a hairy grey-white upper surface and a pore layer that breaks into tooth-like plates with age — never a thick pink-fleshed bracket. Fomitopsis pinicola shares the substrate and general form but has a white pore surface and white context with a resinous red-banded crust, and Postia and Rhodofomes species can be separated by their soft, watery annual flesh.