Found in Eastern North America and Central America
Irpiciporus mollis is the current name for the North American version of the soft toothed polypore. I. pachyodon (formerly Spongipellis pachyodon) seems to be a strictly European species. This collection shows horizontal growth on a fallen tree laying on the ground. More often found on standing trees in a clustered, vertical pattern.
Some woodpeckers favor and are able to detect wood infected with Irpiciporus mollis for excavation of nesting sites. The fungus infects living, standing trees higher up the trunks and make the wood easier for woodpeckers to excavate.
A revised genus-level classification for Cerrenaceae (Polyporales, Agaricomycetes), p.24