254 



Journal of Agricultural Research 



in the filaments, anthers, and pistils of blossoms produced by affected 

 plants. See Table II. 



Table II. — Occurrence of virus in the filaments , anthers, and pistils of blossoms produced 

 by tobacco plants affected with the m.osaic <" 



Experiments with the pistils of plants affected with the mosaic disease 

 were again repeated, using only the upper portion of the style and the 

 stigma. This was done to avoid the possibility of infection from tissues 

 of the ovary adhering to the base of the style when extracted. See 

 Table III. 



Table III. — Occurrence of virus in the iipper portions of the filame7its, arithers, and 

 pistils of blossoms produced by tobacco plants affected with the mosaic disease 



From the preceding experimental data it is evident that the virus of 

 the mosaic disease in affected plants becomes distributed throughout 

 the placental structures, reaching even the ovules themselves. Whether 

 the virus passes beyond the integuments of the ovules to the embryo sac 

 has not been determined. There is some indication that the macerated 

 placenta in a succulent condition is more effective than the immature 



