Apr. 29, 1918 



Anthracnose of LettiLce 



267 



was placed over the leaf where the spores were sown, and the microscope 

 focused upon the surface of the leaf. The spores being hyalin were 

 somewhat difficult to make out with the cells of the leaf as a background; 



Fig. i.-Marssonina panattoniana (X300): A, Germination of spores; B, the same spores two hours later; 

 C, after four hours; D, after six hours; E, after eight hours. 



but with a proper adjustment of the diaphragm and condenser, this was 

 accomplished. By this method it was determined that the required 

 period for germination on the host plant is approximately the same as 



