PLATE I 
Fig. i.—Section of a sugar-beet seedling invaded by Phoma betae , showing distribu¬ 
tion of the mycelium and the action of the fungus on the protoplasm and cell walls. 
X 530 - 
Fig. 2.—Section of sugar-beet seedling showing characteristic action of Phoma betae 
on the cytoplasm and nuclei and cell walls in cases of serious infection. Note the 
gelatinized condition of the middle lamella. X 530. 
Fig. 3.—Section of sugar-beet seedling showing Phoma betae penetrating the cell 
walls and expanding in one of the cells. The nuclei show signs of degeneration. 
X 530. 
Fig. 4, 5, and 6.—Abnormal nuclei from uninfected cells adjacent to invaded tissue 
of sugar-beet seedlings. The nucleus in figure 6 appears to be in the process of direct 
division. X 1,330. 
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