336 s. KUSANO : transpiration of 



Reduced from Table III. Reduced from Table VIII. 



Per cent, of Per cent, of Per cent, of Per cent, of 

 fresh weight, dry wei.2;ht. fresh weight, dry weight. 



Cnifers 8.18 19.72 39.16 93.9 



Foliage everOTeen trees 1G..58 37.74 64.G5 1.50.18 



Katio 1:2.02 1:1.91 1:1.65 1:1.6 



Altliough this slight difference exists in winter, there can 

 be little doubt that in other seasons it would be greater, since, 

 as we have explained in the foregoing paragraph (cf. mode of 

 transpiration), the difference of transpiration in different plants 

 is least during the cold winter but increases more and more 

 when the outer conditions become more favourable. 



The feebler transpiration in conifers can be easily understood 

 when we examine closely their anatomical characters ; the 

 contrivances for protecting transpiration are highly developed 

 especially in this class of plants. Their structures are characterized 

 by the smallness of the transpiring surface, by the lignified cell- 

 layer with its thick wall underlying the epidermis, by the deep 

 depression of the stomata in the epidermis, and by the cuticular 

 layer which attains a considerable thickness, etc.^^ Thus we see 

 that in conifers, the development of xerophilous characters is 

 perfect, while in other evergreen trees it is less so, and this 

 anatomical difference chiefly causes the difference in the mode of 

 transpiration in both kinds of plants. 



VI. Transpiration under Diffused Light. 



In order to understand the process of transpiration exhibited 

 in successive sliort intervals, the method of absorption has been 



1) Onnpare Thomas, Zur vergleichenden Anatomie der Coniferen-Laubhlättcr. Jahrb. 

 f. wLss. Bot., Bd. IV, 18GG, p. 2:3. 



