Weaver: effects of rusts upon transpiration 397 



Whitish spots became visible on the 16th and by the 17th the 

 pustules were breaking out. At the conclusion of the experiment 

 the first leaves of some of both the healthy and rusted plants began 

 to show signs of drying at the tips. Unfortunately, cloudy, humid 

 weather kept down transpiration rates. Nevertheless the appear- 



Fig. 8. Graphs showing the relative transpiration rates of 4 control (light line) 

 and 3 rusted corn plants. 



ance of the rust pustules is at once shown by the increased trans- 

 piration of the diseased plants over the healthy ones. 



Dicotyledons 



A series of experiments was performed to determine the rela- 

 tion of rusts to transpiration among certain dicotyledons. In fact 

 the writer had hoped to include a number of species in this list, but 



