THE DISEASES OF WOUNDS 93 



(it-mi ination consists in sending out a few deli- 

 cate threads from the spores. These threads 

 enter thr moist, decaying parts, branch consid- 

 erably, and at first confine themselves to that 

 portion which is already dead. As they grow 

 farther and farther inward, they may become so 

 well established and so vigorous as to induce 

 (It-ray of themselves. They may encourage 

 the further entrance of air and moisture, and 

 thus continually they may be preceded by the 

 atmospheric conditions necessary for their fur- 

 ther action. At any rate, entrance to the 

 trunk may thus be effected ; and with this en- 

 trance local rotting is induced, and eventually 

 the decay may extend to a considerable portion 

 of the trunk. There are many instances of rot 

 in which the conditions do not favor the forma- 

 tion of the fleshy fructification of the fungus, 

 and the cause of the decay may not be very 



evident. 



f 'In the case of some trees used for timber, 

 and many other deciduous trees, there are well- 

 known rots and decays caused by members of 

 this toadstool family, some of them being pecu- 

 liar to a single species of tree, and others very 

 general in their attacks. Some of these fungi 

 arc truly parasitic, being able to enter through 

 v.-ry small branch wounds, passing rapidly to the 

 sound tissues, where decomposition and decay 

 readily follow. 



