38 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
throughout the day. The same general results were secured with this 
plant as with the other plants studied under similar environment. The 
greatest difference between the osmotic concentrations of the epidermal 
and the guard cells is 19 atmospheres' pressure. 
40 
Fig. 6. Iresine. 
Summary 
The experimental data given in the foregoing charts on the whole do 
not show very great differences in osmotic concentrations between epidermal 
and guard cells. These differences may be summarized as in table 3. 
These results are not in entire harmony with the results of Iljin, since 
the greatest difference here shown in osmotic concentration between guard 
and epidermal cells only approaches the smallest difference secured by Iljin. 
The variations between the results at Ithaca and those at Columbia are 
difficult to explain, but may be due in part (i) to the individual plants 
