6 THE POLYPORACEAE OF WISCONSIN. 



In Oneida and Vilas counties the birch is nearly all defective ex- 

 cept the young growth, which covers the cut-over areas. Many 

 trunks, both living and dead, show numerous pilei of Fomes fomen- 

 tarius, F. nigricans and Polyporus betulinus. Frequently they are 

 also infected with Fomes marginatus, Polystictus pergamenus and 

 Fomes applanatus. The last named, however, was never found on a 

 living birch, but only on much decayed trunks. Fomes applanatus 

 is quite frequently found growing out of wounds in the trunks of 

 living oaks. I have found such specimens near Horicon in Dodge 

 county, Oakfield in Fond du Lac county, and Bangor in La Crosse 

 county. 



In Ashland county the birch is healthier and here it forms one of 

 the most valuable trees for lumbering purposes. In this region 

 Polyporus betulinus is quite rare. Fomes nigricans seems to be the 

 usual cause of disease in the birch here also. Two dead trees were 

 found infected with Armillaria mellea. 



Poplar in all of these regions is infected to quite an extent with 

 Fomes nigricans. populinus, F. fomentarius, Polystictus pergamenus 

 and F. applanatus. Fomes nigricans and Polystictus pergamenus 

 were frequently found growing on living trees with every appear- 

 ance of being active parasites. 



Polyporus Scliweinitzii is a frequent cause of disease in hemlock, 

 fir and white pine, especially in the Shanagolden district. This is 

 the only fungus in the whole region whose mycelium seems to enter 

 the tree through the roots. The rest seem for the most part to gain 

 an entrance through wounds. 



Many other polypores as well as agarics and hydnums were col- 

 lected from decayed logs, stumps, chips and roots, but evidence was 

 not available as to the nature of the decay they produce. One spe- 

 cies, Polyporus maculatus Pk., was frequently found on pine stumps 

 partly or wholly decayed by Fomes ungulatus. Fomes lucidus 

 was , found on hemlock stumps near Glidden, apparently producing 

 a rot peculiar to itself. However, it was never found on standing 

 trunks and the decay was of limited extent. Trametes odorata was 

 found associated with a brown rot not unlike that produced by Fomes 

 carneus, on hemlock logs. I have found this fungus very abundant 

 under bridges and sidewalks at Horicon, Dodge county, Sparta, Mon- 

 roe county and Bangor, La Crosse county, always associated with the 

 same brown rot, sometimes on pine timber but more often on hemlock 

 planks. I have not found it on living trees. Lenzites sepiaria .was 

 found on various species but chiefly on hemlock and tamarack, pro- 

 ducing a brown rot apparently not unlike that of Trametes odorata. 



