4o6 



BOTANICAL GAZETTE 



[DECEMBER 



The transpiration losses from September 27 to December 12 

 from the seven remaining plants are shown in fig. 6. The average 

 total loss during the period of December 12 to February 11 was 

 only 0.7 gm., the maximum and minimum losses being i.o and 

 0.3 gm. respectively. This daily winter loss compared with that 

 of early fall (September 27 to October 10) is only 1/55 as great. 

 It must be noted, however, that it was during this period that the 

 seedlings were winter killed and may have lost more water than 



Fig. 6. — Average daily losses in grams from seven 2-year-old white firs from 

 September 27 to December 12, 191 7. 



normally. On February 11 the leaves were brown and the plants 

 appeared dead. 



The 4-year-old firs, although growing under more favorable 

 moisture conditions (from 5 .3 to 13 .7 per cent available moisture), 

 also succumbed to the dry cold winter. On February 1 1 the leaves 

 were all brown and dead. The transpiration losses to December 19 

 are reliable, however, for up to this time all the plants were in good 

 condition. The leaves did not drop badly, even after drying, as 

 is shown in fig. 7, a photograph which was taken on February 28. 

 Leaf areas for plants 5 and 6 were calculated as for the other white 

 firs. These leaf areas were i .065 and 0.638 sq. dm. respectively. 



