150 jamieson and wollenweber: fusarium trichothecioides 



the tissue about the inoculation pricks. In three weeks time the 

 fungus infection had produced a pronounced effect upon the 

 plants, shown in the wilted condition of the foliage, in the constric- 

 tion of the stem at point of inoculation, and in a brownish black 



Explanation of the Figure 



A,E, F. Conidia of the comma-stage, grown on sterilized potato stems. Fi 

 seen from the back, F 2 , F 3 , extra large and highly septate. B. Conidia of the 

 sporodochia-stage, grown on sterilized grains of corn (twenty days old). C. 

 Conidiophore which in masses forms a dense growth on the surface of the medium 

 like Trichothecium roseum, and produces spores shown in A, E. F. D. Conidio- 

 phore from a sporodochium, that forms the spore shown in B. Magnification 870. 



discoloration of the tissue above and below the constriction. 

 Upon the surface of the discolored area could be seen a growth of 

 powdery slightly pinkish mycelium and spores. Microscopic 

 examination and isolation showed this fungus to be F. trichothe- 



