22 



TIMBER ROT CAUSED BY LENZITES SEPIARIA. 



Ill, fig. 3) and tlie pockets of the rotted wood within (PL II, figs. 1 

 and 2). More or less extensive sheets or strings of matted mycelium 

 may be found throughout the rotted wood. These mats are of 

 varying shades of brown and yellow. A cross section of a decayed 

 timber shows very plainly that it has been rendered totally unfit 

 for use (PI. Ill, fig. 1). In the earlier stages of the disease there are 

 in the sapwood more or less numerous and extensive patches which 

 have turned a dark-brown color, while large fissures run irregularly 

 both radially and between the annual rings, showing that the fungus 

 has caused some ver}" serious changes in the structure of the wood. 

 These patches of rotted wood are generally arranged in pockets with 

 sound wood between them (PI. II, fig. 2). As these pockets grow 



larger the}^ extend 

 radially faster than 

 tangentially. This 

 is partly owing to 

 season cracks which 

 frecpiently open for 

 several inches in 

 depth (PI. II, fig. 1). 

 In general the heart- 

 wood is not attacked 

 (fig. 2), but in the last 

 stages of the decay 

 the outer layers of the 

 heartwood may be 

 more or less affected, 



Fig. 2.— End of a new pine railroad tie, showing many sporophores owing probably tO 

 oiLenzites sepiaria. Note season crack extending to heartwood; flTpii- not liavino" fully 

 also freedom of heartwood from sporophores. ^, 



assumed the char- 

 acters of the older heartwood and also to season cracks opening 

 directly into the heartwood (fig. 2). The outer rings of a peeled log 

 are very commonly not rotted, while those farther in are almost com- 

 pletely disorganized. This difl'erence may be explained by the fact 

 that the sun soon dries out the external layers, so that the fungus 

 has not enough water for its needs. While in the early stages of the 

 rot the annual rings become separated from each other and the fall 

 wood is little affected, in the last stages the fall wood also becomes 

 completely decomposed and crumbles easily between the fuigers. 

 A log which is badly rotted at the end shows the fact by the very 

 numerous cracks which are visible (PI. I, fig. 1). It is noted that 

 tree tops which have the bark left upon them have the sapwood 

 comi)letely rotted where the fruiting bodies show. 



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