THE POLYPORACEAE OF WISCONSIN. 5 



arack, while in others often as high as seventy trees out of one hun- 

 dred are infected. Near Razorback Lake there is a little tamarack 

 swamp of about twelve acres. There are many large trees here hav- 

 ing diameters of over eleven inches and ages of from eighty tb one 

 hundred and twenty years. Here a very large proportion is infected 

 with Trametes pini, Fomes ungulatus, Lenzites sepiaria, Fomes roseus 

 and a very few with Polystictus. 



Of the arbor vitae nearly eighty-five per cent of the older trees are 

 hollow in all of the regions gone over, but no fungus was found which 

 could have been assigned with certainty as the cause, although sev- 

 eral hundred trees were minutely examined. The decay extends over 

 half way up into the trunk and usually down into the larger roots. 

 In these large roots there are often loose whitish or greyish white 

 wood fibres but in the upright trunks the cavities are usually empty. 

 The early stages of the rot could not be found in any of the speci- 

 mens examined. The youngest tree found infected was about two 

 inch3 in diameter and about eighteen years old. This tree had a 

 well formed cavity nearly an inch in diameter, but this cavity did 

 not extend down into the roots. Judging from the appearance of the 

 cavities and the rotten wood, this disease seems to be very similar to 

 the disease caused by Fomes juniperinus described by Von Schrenk, 

 on red cedar. 



In the region studied, maple, at least the hard maple, is seldom fit 

 for lumber. The trunks are quite universally cracked, apparently 

 by frost. This opens the door for wholesale infection. Fomes con- 

 natus, Hydnum septentrionale and Polyporus resinosus are also found 

 in living trees. 



Elm was found only in Ashland county. These trees are tall and 

 graceful, the largest being from two feet to two and one half feet in 

 diameter and at least one hundred and fifty years old. Most of these 

 trees are said to be "shaky" in the butt to the height of about four 

 feet, that is, they are checked and cracked. This, however, does not 

 seem to be due to infection. Fomes nigricans, although not as abun- 

 dant as on maple, produces a rot in the elm similar to that produced 

 in maple by the same fungus. One large pileus which has at least 

 thirty strata was found on a living elm whose interior was quite de- 

 cayed. Polystictus conchifer is often found in the lower dead limbs 

 of the elm, but it was not evident that the fungus was the cause of 

 the death of these limbs. Lentinus Lecomptei grows quite abundantly 

 out of old elm logs or dead standing trunks, but nothing was deter- 

 mined as to its possible presence in living trees. 



