PLATE 4 
A. —Diagrammatic drawing of Kanred stoma representing the average of the meas- 
urements of 20 camera drawings of stoma. 
B. —Similar drawing representing the average Baart stoma. , 
Q _Infecting hypha after attacking a mesophyll cell of Kanred. The contents of 
the host cell are collapsed, and its nucleus nearly dissolved. The haustonum mother 
cell a is shrunken, and the hypha below is plasmolyzed. 
jy_y a ter stage) one mesophyll cell attacked and its contents disordered. In* 
fecting hypha dead, substomatal vesicle still vigorous. ^ , . t1 , . 
L.—Oblique section showing remnant of infecting hypha. Contact wall between 
dead and living host cells thickened. 
