Dry rot The term "dry rot", or "true dry rot", refers to the decay of timbers from only certain species of fungi that are thought to provide their own source of moisture and nutrients to cause decay in otherwise relatively dry timber. However, there has been no published experimental evidence to support the phenomenon. In modern texts, the term 'dry rot' is used in reference to damage inflicted by either: "Serpula lacrymans" (formerly "Merulius lacrymans") predominantly in the United Kingdom and northern Europe; and/or "Meruliporia incrassata" (which has a number of synonyms, including "Poria incrassata" and "Serpula incrassata") in North America. Both
Serpula just behind the head. There is a median, longitudinal, ciliated, thoracic fecal groove on the dorsal midline of the thorax. It is a broad, shallow, relatively indistinct trough running the length of the thorax and ending at the head. Worms of the genus "Serpula" have a distinct abdominal region, composed of up to 190 very short, wide segments. The terminal body region is the tiny pygidium, on which the anus is located. A fecal groove extends the length of the ventral midline of the abdomen. The fecal groove spirals across to the dorsal position as it reaches the thoracic region.