THE POLYPORACEAE OF WISCONSIN. 13 



The specimens of this rot especially studied were taken from a 

 scarlet oak (Quercus coccinea) about one hundred and fifty years old, 

 in the vicinity of Bangor, La Crosse County. The pilei grew out of 

 a large wound and out of the bark just above the wound. Although 

 the wood was decayed to a depth of an inch to one and one-fourth 

 inches, or through twelve to sixteen rings of growth, yet the decay 

 had not progressed more than an inch or two above the wound. Lat- 

 erally the fungus had spread very slowly also. Some dead bark re- 

 mained on the wounded part. Out of this abundant pilei were grow- 

 ing. The new wood formed in the healing part was not affected by 

 the fungus and was gradually covering the decayed wood. The ring 

 of growth next to the one affected was almost entirely sound, form- 

 ing an abrupt boundary line between the decayed and the healthy 

 wood. From this it would seem that it is difficult for the fungus to 

 penetrate the wood radially, from one ring of growth to the next, 

 and that when a ring has been penetrated the infected region is almost 

 completely destroyed before the next ring is attacked. 



The effects on the walls of the cells are about the same in poplar 

 as in the oaks. The ray cells are among the first to be attacked. 



In the poplar the hyphae are quite abundant in all the cells, but 

 in the oak they are less abundant. Here, as in the case of P. abietinus, 

 the largest and the most abundant hyphae go through the cells length- 

 wise. They give off smaller branches, which penetrate the lateral 

 walls. Sometimes the hyphae go through the pits. 



Lenzites sepiaria Fries. 



Though not a polypore, I shall describe this fungus here because 

 of its similar habit and relation to decay of timber. This fungus is 

 easily recognized by its sepia brown color with lighter margin. At 

 every rain, during the first part of the season, this margin seems to 

 revive and grow. The gills when first formed are of a light cream 

 color like the young margin but on maturing the whole fungus grows 

 dark. 



L. sepiaria is a very common fungus in all parts of Wisconsin, grow- 

 ing chiefly on hemlock, pine, spruce and tamarack. During wet sea- 

 sons the pilei are found growing abundantly out of bridge timbers, 

 planks in sidewalks and sleepers. In the forest the pilei were found 

 on fallen trunks of tamaracks, white and red pine, and spruce. They 

 were more rare on dead standing trunks and were never found on 

 living trees. 



