334 MINNESOTA BOTANICAL STUDIES. 



The question now naturally arises whether the symbiosis was 

 established previous to or subsequent upon the origin of these 

 species. In other words has the symbiosis arisen once or three 

 times ? The simpler explanation seems at first to be that the 

 symbiosis was previous. This would however presuppose the 

 development in each of the three species of two parallel lines 

 one with and one without the fungus. On the other hand a 

 subsequent establishment of the symbiosis would require like 

 results for the same fungus or for several closely related fungi 

 attacking three species of Lolium. A fuller knowledge of the 

 inter-relations between these species as well as of the remaining 

 species of Lolium is necessary before an intelligent opinion on 

 this point can be framed. 



