Fraser: Cultures of Heteroecious Rusts 71 



geographical distribution of the form on Pyrola would favor this 

 assumption. As the uredinial and telial stages were very common 

 on Pyrola americana Sweet and P. elliptica Nutt, their develop- 

 ment was watched during the spring and early summer of last 

 year, and the cones of the spruces in the vicinity were also kept 

 under observation for evidence bearing on these suggestions. 



By May 7 many of the uredinia were mature and the spores 

 were escaping. The telia were first noticed germinating on May 

 20, and by May 23 germination was general. At this time the 

 young pistillate cones of Picea canadensis were open and in a 

 few days those of P. rubra and P. mariana were in the same con- 

 dition. By the first of June the teliospores had pretty well germi- 

 nated and no germinating material could be found on June 10. 

 The cones of the spruces in the vicinity were closely watched for 

 the appearance of pycnia. Their first appearance, as indicated 

 by the yellow color of the scales, was on June 21, and by July 4 

 they were common. Owing to my absence, the place could not be 

 visited again until July 17, when it was found that the aeciospores 

 of Peridermium conorum-Piceae were being shed very abun- 

 dantly from the cones of Picea mariana in the vicinity of the 

 rusted Pyrola plants. The cones of the young trees that were 

 easily accessible were found to be generally infected, and many of 

 the cones on the larger trees were also infected. The Perider- 

 mium is conspicuous at this time, and the aecia-bearing cones 

 could be seen at a considerable distance. As far as was observed 

 the Peridermium was confined to the vicinity of the Pyrola plants 

 that bore germinating telia in the spring. 



The field evidence strongly supported the view that these forms 

 are connected, and tends to confirm the statement of Arthur and 

 Kern (1. c.) that the Peridermium is common though not often 

 collected. 



Calyptospora columnaris (Alb. & Schw.) Kuehn 

 A collection of the aecial stage of this rust was reported from 

 Pictou last year (Science 30: 814. 1909). It was then found 

 to be generally distributed but rather sparingly developed in any 

 place. Observations were begun earlier in the spring of 1910 

 and well developed aecia were collected on June 21. The aecia 



