332 s. KUSANO : transpiration of 



In Quercns and Fatsia, the epidermal wall is very thin, 

 in fact the thinnest among the plants employed in my experiments, 

 having the upper wall 5 /^ in thickness and the lower wall about 

 half as thick. The fact that the greatest amount of water was 

 transpired by Quercus can no doubt be attributed to this 

 peculiarity of the wall, as well as to the large number of 

 stomata (the largest number among my plants reaching 557 per 

 D mm.). The last mentioned number is very remarkable if we 

 make comparison with other plants, for example with Fatsia, which 

 has only 182 per D mm. 



The epidermal walls in Photinia, Da'pliniylnjlluni and Illicmm 

 have nearly the same thickness, viz. from 8 to 0).^) /^ in the upper, 

 and from ^.k> to 6 /i in the lower sides. In the first two plants, 

 we have just the same number of stomata, viz., 300 per D mm ; 

 while in the latter a smaller number, viz., 218 per D mm., but 

 with greater dimension. As the variation in the anatomical 

 characters of these plants is slight, so the amount of water trans- 

 pired by them differs only a little (see Tables I-VIII). 



The remaining plants have rather thick epidermal walls ; 

 thus in Plltosjyorum, the thickness is 14 fx in those of the ujoper 

 side, and 9 1^ in the lower ; in Ternslrœmia 10 /i in the upper, 

 and 10-5 /i in in the lower ; and in TJica 10-5.5 />« in the upper, 

 and 10-4 /^ in the lower. In spite of the well developed epi- 

 dermis in Pittosporum, we observe that the amount of trans- 

 piration is far greater than in the case of Photiriia, Illiciuvi and 

 Fatsia^ all of which have thinner cell-walls. This difference is 

 most probably due to the larger number of stomata in the first 

 named plant. 



A seemingly exce})tionul case is observed in Ternslrœmia, 

 where in spite of the tolerably large size of the stomata and the 



