Coniophora puteana - Brown Rot Fungus

wet rot coniophora

Coniophora puteana is a type of brown rot fungus commonly called also the "cellar" fungus. Despite its name Coniophora puteana can be found literally anywhere in the building usually around the places with active water ingress in to the building, near break in walls, crack pipes or places with unusually high condensation.


 In contrast to other common wet rotting fungi Coniophora puteana requires relatively high level of moisture to spread and proliferate.  Its optimal moisture content in material is 50 - 60%. Coniophora puteana primarily attacks the wood of conifers in its natural habitat and occasionally the wood of broad-leaved trees, including citrus trees.

Coniophora puteana causes timber to darken and produces longitudinal cracks usually under a very thin layer of good wood. This wooded decaying fungus thrives in very damp areas like the basement, roof and solid wood floor.  Strands that look like black ferns can be observed on the surface but do not spread to adjoining timber but confined to the damp area.

The mycelium is not always present - it tends to develop under humid conditions such as behind damp skirting etc, as a blackish to olive-brown sheet. It forms  light to dark brown fruit bodies with warty knots  have an indistinct and fibrous margin, are firmly attached, fragile when dry and produce yellow-brown spores. The strands are first white, soon brown to black, to 2 mm wide, to 1 mm thick, root-like, hardly removable and fragile, partly with brighter centre and occur often also on brickwork and other inorganic substrates. The pale to brown, branched fibres are somewhat thick-walled, however with relatively broad and usually visible lumen.

wet rot coniophora

Coniophora puteana is bounded by a white margin. If no mycelium is present then it can be difficult to identify from other brown rots. In most cases the rot is internal and leaves a very thin skin of sound wood at the surface. This can be used to suggest the damage might be cellar fungus. Mycelium and strands can develop away from the wood over the surface of very damp masonry and other surfaces under very humid conditions. Frequently, fine brown/black strands emanate from rotting wood and these are quire delicate and do not become brittle on drying.

It is one of the most common species in new buildings but it can just as easily be found in old buildings, on stored wood, timber in soil contact like poles, piles, sleepers and on bridge timber as well as rarely on stumps and as wound or a weakness parasite on living trees