Serpula himantioides is a fungal pathogen within the division
Basidiomycota. It produces thin, resupinate (inverted), membranous fan-like
basidiocarps that are brownish in color and appear as distinctive fruiting bodies on the exterior of the host.
S. himantioides prefers the moist wood of
coniferous hosts such as
fir,
larch,
spruce, and
pine. It is the causal agent of
butt rot disease, the symptoms of which include rotting the heartwood at base of tree, as well as damage to the tap root and cores of lateral roots, but standing trees show no signs of infection. It also a common cause of timber rotting in buildings, which has made this pathogen difficult to differentiate from
S. lacrymans because of their similarities. This disease often goes unnoticed initially due to a lack of any above ground symptoms of disease. Signs of the pathogen include basidiospores, and fungal masses that are generally dark brown and membranous in the center but become thin white mycelium towards edges of the mass. The brown cubical rot caused by
S. himantioides resembles the rots of
Phaeolus schweinitzii and
S. lacrymans. ==Importance==