AN UNDESCRIBED TIMBER DECAY OF 

 PITCH PINE 1 



L. O. OVERHOLTS 



(With Plates 12 and 13) 



In the vicinity of State College, Pennsylvania, the pitch pines 

 (Pinus rigida) are dying rather rapidly, especially in the more 

 open woodlands. Most of these trees are fairly mature and the 

 cause of their death has not been satisfactorily determined. The 

 effects of the pine bark borers are very evident just beneath the 

 bark of the dead trees, but whether or not they are responsible 

 for the injury cannot be stated at present. Within a few months 

 after the trees die, and while they are yet standing, they often 

 become heavily infected with the "blue stain" fungus (Cera- 

 tostomella pilifera) as evidenced by the extensive bluing of the 

 sap wood. After the dead trees fall they are subject to the at- 

 tacks of several of the wood-destroying fungi. The most im- 

 portant of these are Polyporus abietinus (Dicks.) Fries and Poly- 

 porus amorphus Fries. In fact, the sporophores of these two 

 species are the only ones that have ever been found on timber 

 decayed in the manner described in this article. The decay pro- 

 duced by P. abietinus is well known and abundant on both pine 

 and hemlock wood in this vicinity. It is entirely unlike the decay 

 described here and cannot be considered in this connection. The 

 decay produced by P. amorphus has not been studied in pure 

 culture inoculations but the evidence at hand is such as to leave 

 no doubt that the effects here described are due to the mycelium 

 of that fungus. 



The Fungus and Its Identification 



Polyporus amorphus has been considered to be quite rare in 

 this country. Specimens submitted to the New York Botanical 



1 Read before the Botanical Society of America at the New York meeting, 

 December, 19 16. Contribution from the Department of Botany, The Penn- 

 sylvania State College, No. 11. 



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