340 s. KusANO : transpiration of 



Thus, among twenty kinds of plants, the intensity of trans- 

 piration did not exceed 0.1 gram per D dm. per hour in 

 diffused light. The greatest activity of transpiration was attained 

 by Oymnogramme japonica, a species of fern ; it has thin herbaceous 

 leaves, whose anatomical structure is characterized by the 

 pallisade consisting of cells loosely arranged in one layer, and 

 also by having an imperfectly developed cuticula. This fern, 

 which grows in sheltered places, sheds its leaves in winter when 

 it is found in open tracts. In such a slightly xerophilous plant, 

 it is natural for us to expect a considerable loss of water. On the 

 other hand, we see the least amount of transpiration in Aspidistra 

 elatior, a monocotyledonous plant, whose cuticula is very thick, 

 the mesophyll consisting almost entirely of compactly arranged 

 parenchyma. Between these two extremes of transpiration stand 

 the typical evergreen trees, ivhich emit, on an average, 53 mgr. of 

 water per ^ dm. per hour. Among these evergreen trees again, 

 the maximum amount is attained in Quercus glauca, while the 

 minimum amount is found in Ilex crenata. 



We see in our experiments, that the relative amount of 

 transpiration in pot-plants on one hand, and in cut-branches on 

 the other, do not correspond with each other, as for instance, tlie 

 amount transpired by the cut-branches of Thea japonica was 

 greater than that of Pittosporum ; while in the case of potted 

 plants, the former was surpassed by the latter. This diversity 

 in the amount of water transpired in the two different cases is 

 partly due to the difference of conditions (temperature, humidity, 

 light &c.) under which the experiments were made ; but chiefly 

 to the methods of the experiments, for in one case the entire 

 plant was used, while in the other only a part was employed. 

 Moreover the difference between individual plants, and also between 



