FUNGI OF IMPORTANCE IN THE DECAY OF TIMBERS. 15 



sporophores. Sporophores collected near Providence which had 

 overwintered were made to cast spores abundantly in April, 1920. 



The fruit bodies of Trametes serialis studied were those, already 

 referred to, which were formed in the fungus pit in the forest-path- 

 ology greenhouse at Madison, Wis* This fungus fruited on the tim- 

 bers each fall from 1916 to 1919. It is not known whether fruiting 

 occurred at other times. The sporophores were few in number and 

 the total hymenial surface never exceeded 150 square centimeters. 

 These small fruit bodies, however, liberated large numbers of spores. 

 Figure 1 of Plate VI shows visible prints from one small one during 

 two or three days on a vertical surface where the hymenial surface 

 was not large, and it is likely that only a small part of the spores 

 cast were caught on the surfaces shown. In a single day resupinate 

 sporophores cast thick crusts of spores on glass slides and continued 

 to do so for several days. All of the basidiospores of Trametes 

 serialis used in this work for three winters came from heavy casts 

 made in the fall of 1916. Three fruit bodies formed in November, 

 1919, were kept under observation in order to obtain some idea as 

 to the length of the casting period. Fruiting was first noted on 

 November 18 and casting had already begun. It continued for 15 

 consecutive days. 



These fruiting bodies of Trametes serialis were formed in the dark. 

 The largest one was kept in the dark for the whole period of 15 

 days, and the two smaller ones were put in a moist chamber in the 

 light in the laboratory. Spores were cast abundantly in both places. 

 On the fifteenth day the sporophores began to turn brown at the 

 edges and shrivel up, although in an atmosphere practically satu- 

 rated, and these parts became attacked by molds. On the next day 

 the browning and shriveling had proceeded farther and the molds 

 had spread. The simultaneous cessation of casting and encroachment 

 of molds was striking, as was the absence of molds on the delicate 

 hymen i a during the 15 days of sporulation under very humid con- 

 ditions. The same phenomenon was observed in the tests on the cast- 

 ing of spores by Lenzites sepiaHa, as molds did not make their ap- 

 pearance until after the sporophores had ceased to cast spores. The 

 spent fruit bodies of Trametes serialis left in the fungus pit soon 

 d i -appeared. When dried artificially, they became very thin, fragile, 

 and distorted, but in the pit they disintegrated through attack by 

 molds and consumption by sow bugs. 



The writer has never succeeded in obtaining basidiospores from 

 the perennial form of Foirus ramus. From the annual form spores 



are usually east sparingly. In the Laboratory risible prints have been 

 obtained onlj occasionally. Attempts to obtain prints out of doors 



were made at ( raw fords. N. II.. in September, L910, during a pro 



