6 BULLETIN 722, IT. S. DEPARTMENT OF AGRICULTURE. 



Tlie fungus is most abundant and of greatest consequence in western 

 Montana, Idaho, Oregon, Wasliington, and British Columbia. 



THE DISEASE CAUSED BY ECHINODONTIUM TINCTORIUM. 



OUTWARD SIGNS OF THE DISEASE. 



To be able to recognize or discriminate between the more dangerous 

 and less harmful diseases should be a part of the everyday knowledge 

 of the forest officer in charge of the marking. The following state- 

 ments will be of some value in this respect. 



The decay-producing fungus proper is the mycelium in the wood, 

 not the "conk" (fig. .5) without. The appearance of a fruiting body 



Fig. 3. — Sporophore of Echinodontium tinctorium, showing upper surface. 



is in most cases an index of the intensive development of the fungus, 

 at least within a certain volume of the tree infected. It means that 

 a good part of the food materials of the heartwood at that point 

 are exhausted. A single average-sized sporophore situated on the 

 first 16 feet of the trmik for aU practical purposes may be taken to in- 

 dicate an munerchantable condition of the heartwood of aU pomts 

 below and into the next 16-foot log above the first. A sporophore 

 situated weU up on the trunk may be taken to indicate undesirable 

 material throughout the main part of the tree. Little need be said 

 concerning the presence of more than one sporophore. It will be 

 observed that the largest usually has smaller ones above and below it. 



