The real dry rot (Serpula lacrimans) heard to the department real fungi (Eumycota), class pillar-fungi (Basidiomycetes), order Aphyllophorales, family wart-sponges (Coniopharaceae) types Coniophora and Serpula. In the Brockhaus, it is assigned respectively to the Löcherpilzen in the Brockhaus biology to the Porlingen with the name Merulius lacrimans (= Merulius domesticus). The white pore-sponge belongs to the family Porlinge, Poriaceae, for example, Poria vaporaria, that because of the similar damage-picture, brown die-break (Destruktionsfäule) is confused. The real dry rot is known also under the name Merulius lacrimans. The kind Merulius was positioned from frieze after purely outward characteristics what also was not differently possible at this time surely. To this family Fältlinge, Meruliaceae, the hellsporigen types are taken into account. By Persoon, the braunsporigen salespersons were classified according to the kind Serpula.