140 



PLANT DISEASES 



Its presence is often first indicated on the primary 

 leaves of seedlings by the appearance of brown blotches, 

 the remainder of the leaf becoming purple red. 



' A condition of the fungus termed spermogonia, forming 



Fig. 27. Lophodermivm pinastri. i, leaves 

 with the fungus, natural size ; 2, ascigerous form 

 of the fungus, mag. ; 3, spermogonium of the 

 fungus, mag. ; 4, ascus containing eight spores, 

 also two paraphyses, highly mag. ; 5, a single spore, 

 highly mag. 



smaller black spots than the elliptical, ascigerous form, 

 often appears first on the leaves, which it kills. The pre- 

 sumed reproductive bodies, called spermatia, formed in the 

 spermogonia, have not been observed to germinate. The 

 mature, ascigerous form only opens for the escape of the 

 spores after long-continued rain, which thoroughly soaks 



