EVEEGKEEN TREES IN WINTER. 



333 



abimdaiice of the intercellular spaces (Fig. 3), the amount of 

 transpiration is very small, even less than that of FUtosporum 

 which has smaller stomata and narrower intercellular spaces, al- 

 though the number of the former is somewhat greater. This may 

 probably be due to the checking of stomatal transpiration in winter, 

 as may be seen by comparing the amount of transpiration at the 

 end of March (vide Table VIII), when the amount suddenly in- 

 creases, owing to the recovery of the function of the stomata. 



Fig. 3. 



Cross-section of a leaf of Ternstros)nia japonica showing 

 the large intercellular spaces. X 97. 



The amount of transpiration in Thea is a little greater than in 

 Terîisérœmia, but less than in all the other plants which I examined. 

 Here, we see that all parts of the epidermal wall are thickened, 

 the intercellular spaces become smaller, and the number of 

 stomata amounts only to 293 per D mm.; all these characteristics 

 point to the fact that this plant has well developed protection 

 against transpiration in winter. Moreover, in Thea the increase 



