176 



Mycologia 



Many of the host plants used in the cultures were obtained in 

 the field and placed in pots in early spring, but some were pro- 

 cured a short time before the experiments were made. Care was 

 taken to select the plants remote from any source of infection and 

 the surrounding plants of the same species from where they were 

 obtained were kept under observation and remained free from 

 infection except in one case which is noted in the description of 

 the experiment. Plants from the same place as those used for 

 the cultures were also kept as checks in every experiment and in 

 no case did infection appear. 



The experiments were carried on in a well-lighted laboratory 

 of Pictou Academy, with the exception of one at the end of 

 the season which was performed at the Agricultural College, 

 Truro, N. S. 



The writer's thanks are due to Dr. J. C. Arthur for val- 

 uable suggestions and assistance, to Professor H. W. Smith, 

 Biologist of the Agricultural College, Truro, for enthusiastic and 

 valuable assistance in field observation in the vicinity of Truro 

 and in the culture carried on at the College, and also to Mr. John 

 Macoun, Naturalist of the Geological Survey of Canada, for 

 determining some of the host plants. 



PUCCINIASTRUM PUSTULATUM (Pers.) Dictcl 



During the summer of 1910 there was a very luxuriant devel- 

 opment of this rust on Epilobium angustifolimn L. in a small area 

 that had been previously swept by fire. The leaves with telia 

 were collected the following spring and gave excellent germina- 

 tion after from four to six days in a moist chamber. A sowing 

 was made on Abies balsam ea on May 17. Pycnia were noticed 

 on May 24 and aecia on June i. Another sowing on May 22 

 gave pycnia on May 29 with aecia on June 4. Infection was very 

 marked in both cultures, practically all the young leaves being 

 infected. Another sowing was made on June 19 with a few 

 pycnia on June 27 and aecia on July 4. By this time the leaves 

 of the host plants were becoming mature and the infection was 

 sparing. A sowing was also tried on Tsuga canadensis but with- 

 out result. 



Aeciospores from the culture aecia were sown on Epilobium 



