destructive iff te wood of hemlock trees in the Northwest, and 

 of species of Abies wherever found in the V/est, It is not 

 qj ent to find 50 to 90 per cent of mature trees diseased "by it, 

 and rendered useless for lumber or timbers. 



A rot unaccompanied by sporophores similar to the one pro- 

 duced by Echinodontium tinctorium occurs occasionally in Pinus 

 ponderosa, Pinus contorta, and Thuja plicata. In general, hoxrever, 

 the fungus occurs on species of Tsuga and Abies, almost to the ex- 

 clusion of other heart-rotting fungi, as in the case of Trametes pini ; 

 infection apparently taking place later in the life of the tree, and 

 the former fungus inhabits the heart of the tree, to the exclusion of 

 the other. 



Polyporus sulphureus (Bull.) Fr., or a f o m of this species 

 of fungus causes a red-brown rot of conifers, attacking both heart 

 and sap wood. The rot caused by this fungus, resembling very much 

 in color and appearance that caused by Pomes laricis, and to some 

 -extent that caused by Fomes pinicola f.Sw.) Cooke. It is rarely 

 found fruiting on living conifers. The wood of the following spe- 

 cies is attacked by Polyporus sulphureus: Abies grandis, A. nagnif- 

 ica, Larix occidentals, Picca engelaanni, Pinus contorta, P. 

 monticola, P. ponderosa, P. Jeffrey!, Pseudotsuga taxifolia, and 



Tsuga heterophylla. 



Pclyporus amarua Hedgo. is the cause of the pin rot or pc 

 ness of the incense cedar (Librocedrus decurrens) in Oregon and 

 California. From 50 to 90 per cent of the older trees in this 

 region are affected to some extent by this fungus, causing a great- 

 loss in the wood products of this valuable species of tree. 



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