PLATE IX. 



Fig. 1. Potato-tuber showing pronounced wart at toe or crown. The malformed 

 sprouting eye and roots may be seen in the midst of the distorted 

 tissue. (Natural size.) 



Fig. 2. Section through the convoluted surface of the wart showing numerous 

 ' resting spores.' (Magnified.) 



Fig. 3. A macerating piece of the wart showing numerous ' resting spores ' as 

 black dots. (Slightly magnified.) 



Pig. 4. Microphotograph of a single resting sporangium, showing the angular wall 

 and the separate zoospores. 



Fig. 5. Vertical section through a diseased eye 



Fig. 6. The same more highly magnified. 



Fig. 7. An artificially ruptured sporangium, from Flemming-fixed material 

 The individual zoospores are clearly recognizable. 



The mass of zoospores is enclosed by the inner wall as a membrane, and 

 to the left the dark edge of the ruptured outer wall is just visible. 



