DISEASES CAUSED BY WOUND FUNGI. 39 



hum of the sulphur polyporus usually enters the trees in the crown 

 i s hardly practicable to attempt wound treatment. The chief 

 endeavor therefore, must be concentrated on the removal of he 

 diseased trees. Any tree which shows signs of development of por" 

 phores of Polyporus sulphureus should be cut down at once and all 

 of tl, wood affected with the mycelium of this fungus shouhl be 



PIPED-KOT OP OAK AXD CHESTXUT. 



The disease which we distinguish under the name "piped-rot" 

 si eaally affects oak trees particularly those of the black oak group. 

 in . V ' *£ L > Jt has also been found in the beech (Foam atro 

 T^cea (Marsh.) Sudworth) and yellow birch (BetulaLaZ^ )' 

 Tin, disease has been found widely distributed throughout the decid- 

 uous forests of the Mississippi Valley. 



A similar disease, which is probably caused by the same fungus 



occurs in he chestnut (Castanea dentata (Marsh.") Borkh ) (PI V 



fig. 2.) The heartwood of affected trees has a mottled appearance' 



showing irregular small, pocket-like patches of white fibers teZ- 



ated by wood fibers still retaining almost the normal color o The 



mile . V Vhlte a T &St 8ppear » the ™> d ; » ** form o 

 nal v tit It 1 " ar , e r'; Vhich gradUaI1 - V inCrease in size l ™^- 

 dme 'the , £ WMe ' eCOme C ° nflUent ' S0 that i]1 the course of 



time he wood frequently shows a series of irregular white lines 

 extending longitudinally. As the disease progresses the white 

 change mo small pockets, or holes, lined with fibers. Where these 

 holes reach any size they frequently become filled with a dark red- 

 brown mycelium In its last stages the diseased wood is composed 

 of oose masses of white fibers mixed with the brown mycelium an 

 inclosed by thm unaffected layers of wood. The preliminary- st^ 

 of the disease are characterized by a darker coloration of the heart- 

 wood, winch starts near the center of the trunk, gradually spreading 

 outward until it reaches the sapwood. In Plate V, figure I 2 

 darker coloration shows on the boundary between the -parti 1 

 decayed wood and the sapwood. 



It will b e noted that the disease is confined strictly to the heart- 

 en 1 ,K ^^ Th t ChMlgeS jUSt described <"&>«* ^ar some 

 branch stub, very much as has been described for Fames igniarius. 

 Without referring ,n detail to the microscopical changes which take 

 pace m the wood, it may be said that the white areas are due to a 

 hmng of cellulose fibers, which stand out more or less separately 

 from one another, on the inner surfaces of the cavities 



The piped-rot is one which is readily distinguished from all other 

 diseases of deciduous trees on account of the speckled character of 



