THE RUSTS OF NO\ 7 A SCOTIA. FRASER. 



The descriptions that follow are based on the collections 

 of Nova Scotia material. It was necessary when certain forms 

 were not collected or when the collections were scanty to make 

 use of the systematic literature cited at the end of this paper. 

 These oases are recorded in the notes that follow the descrip- 

 tion of the species. 



An interesting feature of the work was the field study 

 with the object of connecting aecial and telial stages and the 

 culture experiments undertaken to test the clues thus obtained. 

 As a result the life histories of a number of species previously 

 unknown were worked out. These are noted under the 

 descriptions of the species. 



A 50$ solution of lactic acid was used for the purpose of 

 clearing the sections and swelling the spores to their normal 

 shape and size. This is necessary in the case of the spores of 

 the Puccinia Hieracii type, as the dried spores are much con- 

 tracted and wrinkled. The spores or sections were placed on 

 a slide and a drop of the lactic acid solution added. The slide 

 was then heated over a spirit lamp and the liquid was brought 

 to the boiling point or allowed to boil for a few seconds. 

 This also brought out the germ pores more clearly. - 



The drawings are made with the aid of a camera lucida 

 to a uniform magnification of 480 diameters, except in a few 

 cases noted in the descriptions accompanying the drawings 

 which are reduced to one-half the diameters in the photo- 

 gravure process. 



Gray's "New Manual of Botany" was used in deter mining 

 the host plants. 



The writer is deeply indebted to Dr. J. C. Arthur for 

 valuable suggestions and for the determination of doubtful 

 species. He is also indebted to John Macoun, Naturalist, 

 Geol. Survey Dept. of Canada, for the prompt determination 

 of a few doubtful host plants. 



