(4°3) 



repeating spores. It suggests that the species of Gymnosporan- 

 gium are different from the other heteroecious rusts chiefly in the 

 lack of repeating spores and that if in the past such a stage existed 

 that this group would have conformed very well with other 

 heteroecious groups. 



TABLE III. 



In order to gain some idea of the different "affinities" existing 

 between the host genera of the antithetic phases, a study of the 

 number of species alternating between the various antithetic 

 hosts has been made and the data are graphically presented in 

 table III. It is not likely, though, that the number of species 



