Dry Rot

Serpula lacrymans


Appears in



By Roger Phillips

Published 2006

Dry Rot Serpula lacrymans (Wulfen) J. Schröt. (illustrated 40% life size) Fruit body 5–50cm across, usually resupinate but also occasionally forming brackets on vertical substrates, margin thick; arising from a whitish, pinkish, lilac, or grey mycelium. Flesh 2–12mm thick; greyish-white; spongy-fleshy. Pores rusty yellow, becoming more yellowish towards the white, sterile margin. Spores 8–10×5–6¼, elliptical; rust-brown. Habitat on worked wood in buildings, although the fruit bodies of the fungus may also appear on non-organic substrates such as plaster or brickwork; all year. Occasional. Not edible. Note photographed by Alan & Patie Outen.

Infection of wood occurs when it has become sodden for some time, following prolonged damp due to leaking roofs or pipes, and is either by spores or by vegetative mycelium spreading through brickwork. On germination of the spores, the mycelia exhibit two distinct modes of growth. In the first, numerous fine hyphae penetrate the wood, producing enzymes that break down the wood and enable the fungus to absorb nutrients; as the wood dries it cracks into cubical blocks and eventually disintegrates into brown powder. It is the second mode of growth that is most easily detected, because it takes the form of thick mycelial cords and spreading cottony sheets which enable the fungus to travel over areas from which it cannot derive nutrients, such as brickwork or metal. The fruit bodies arise from these mycelial cords. This is a very destructive fungus that should be dealt with as soon as it is detected. The distinctive sweet. mouldy smell will help determine its presence; thereafter look for the shrinking woodwork.

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