4o8 



BOTANICAL GAZETTE 



[DECEMBER 



Attention has already been called to this phenomenon in case 

 of both the yellow and jack pines, and figs. 9 and 10 show the same 

 occurrence for the spruce and Douglas fir. Although this phenom- 

 enon was not examined carefully at the time, for it was not known 



Fig. 9. — Average daily losses in grams from battery of eight 3-year-old spruces; 

 September 28 to December 13, 1917. 



Fig. 10. — Average daily losses in grams from battery of three 3-year-old Douglas 

 firs; September 27 to December 19, 1917. 



to occur until after the final weighings on November 16 were plotted, 

 the irregularity is probably due to the individuality shown by the 

 several plants in the rapidity of permanent closure of the stomata, 

 and a general slowing down of the vital activities as the temperature 

 decreased. 



