FiisariuDi ui Tuber Rot and JJUt of Potato 35 
would ha\e to destroy a tissue whose walls are mainly cellulose 
bv intercellular activity, while one that could digest cellulose might 
^ Be 
Fig. i:-). — Fusariiiiii trichothecioidcs and F. oxysponaii on sterile potato 
cylinders: .-i. C. cylinders inoculated with f. oxysporuDi . incubated for 2 
days at 25' C.; B, cylinder inoculated with F. trichothecioidcs. incubated for 
2 days at 25' C. 
destroy this tissue by a primary cell invasion. Again, a greater 
ability on the part of an organism to digest suberin. other things 
