PLATE II 



Fig. I. — Section through a sugar-beet seedling which has recovered from an attack 

 of Phoma beiae, showing a young pycnidium of the fungus forming on the discarded, 

 killed tissue. X 500. 



Fig. 2. — Longitudinal section tlirough a sugar-beet seedling which had recovered 

 from an attack of root sickness due to Phoma betac, showing the presence of the fungus 

 established in a condition of reduced virulence in the living cells. X 530. 



