MICHIGAN ACADEMY OF SCIENCE. 53 



NOTES ON GANODERMA SESSILE MURRILL.— ITS VARIATION FROM THE 

 ORIGINAL DESCRIPTION AND POSSIBLE PARASITISM. 



Jas. B. Pollock. 



Murrill has recently described a new species of a genus of the Polyporacea? under the 

 name of Ganoderma sessile (Bull. Torr. Bot. Club, 29: 604—5, 1902), a fungus of which 

 specimens had been collected in Indiana, Ohio, New York, New Jersey, Alabama and 

 Louisiana, and which had been referred to Ganoderma pseiidoboletus (Polyporus lucidus 

 Fries) . 



The writer collected specimens of this fungus in two localities in the summer and au- 

 tumn of 1904, on the University campus at Ann Arbor, and in Allen's woods, eleven miles 

 west of Ann Arbor. Some of the specimens differed from the description given by Murrill 

 to such a degree as to make it desirable to record these differences, and one of the collec- 

 tions was made in a situation which suggested that this fungus might be a parasite. 



In July, 1904, a man trimming up trees on the L'niversity of Michigan campus reported 

 that he had removed a large fvmgus from the trunk of a certain hard maple tree, which 

 was alive but evidently much behind its neighbors in vitality and vigor, as shown by the 

 small size of its leaves, the less density of its top, and the smaller size of the top as com- 

 pared with other trees growing in the same row, and presumably of the same age and in 

 similar conditions. The difference between this tree and its neighbor was very marked, 

 and the cause apparently must have been active more than the present season. The situ- 

 ation suggested a probable cause. Two or three years previously new concrete walks had 

 been laid in this part of the campus, and three of these had been laid near enough to this 

 tree to come under its spreading top, and presumably a large proportion of roots of this 

 tree must have been cut off in making the excavations for the walks. Since the trees on 

 the campus vmder the best conditions suffer for lack of water during the dry periods of 

 the summer season, the loss of water occasioned by a considerable loss of the root systein 

 on three sides of this tree might account for the reduced vitality, which the whole appear- 

 ance of the tree indicated. 



The fungus mentioned above as having been removed from this tree had been carted 

 away and could not be found. But the tree was kept under observation for several weeks 

 following, and in August the fungus reappeared, developing the sporophore in the same 

 place from which it had previously been removed. This was directly on the trunk, just 

 at the top of the ground, and even partly below the ground. It extended around the 

 tree for six or seven inches, and the pores characteristic of the family Polyporacese began 

 to develop when there was only a thick, rather irregular crust, and the fungus in this place 

 did not take the typical bracket form of many Polyporacese. 



In addition to this growth on the tree, several other sporophores made their appear- 

 ance, not on the trunk of the tree, but on the ground a few feet from it, in the direction of 

 the nearest walk. These specimens were gathered and placed in the collection of the 

 University. In October the growth was again found both on the trunk and on the ground 

 in about the same spot as before. These were gathered by a class engaged in the study of 

 plant diseases. 



In Octolier also the collection was made in Allen's woods, the specimens being on the 

 ground, on different sides of, and near to a dead red oak tree. The specimens on the ground 

 were stipitate, while Murrill describes the species as sessile only, though in the notes fol- 

 lowing the technical description he cjuotes Morgan as having found it with a stipe, though 

 Morgan referred it to Polyporus lucidus Fr. 



The situation of these stipitate specimens suggested that they might have developed 

 on roots of the trees near which they were found. Attempts to trace two of them to roots 

 did not succeed, but still left the question unsettled. One of these specimens had a single 

 central stipe for a group of connate pilei, which started outward and upward. Where 

 the pilei were single the top was horizontal, the outline almost kidney shaped with the 

 indentation at the point of attachment of the stipe, the latter being vertical, and more 

 or less irregular. 



There is no doubt whatever that the specimen sessile on the maple trunk and the stipi- 

 tate specimen on the ground are the same species. They developed together when re- 

 moved, and all show exactly the same characteristics in all particulars except shape. Nor 

 does there seem to be any doubt that these specimens agree with IMurrill's G. sessile. They 

 show exactly the characters by which he distinguishes this species from G. pseudoboletus , 



