90 



A MONTANE RAIN-FOREST. 



piration (as distinguished from the transpiration of the lower surface) 

 are found to be from 42 to 48 per cent of the total transpiration of the 

 leaf. In other words, in Diplazium the total epidermal surface of the 

 leaf loses at all times slightly more water than the stomata. 



The relative stomatal and the relative cuticular transpiration have 

 been calculated from these readings (table 34, K, L). A comparison 

 of these two sets of relative transpiration figures shows that the fluctua- 

 tions in the diurnal march of the relative cuticular rate are only slightly 

 less than the fluctuations of the relative stomatal rate (see fig. 14). 

 This evidence indicates that the irregularities of relative transpiration 

 rate are due to some physiological regulations other than the opening 



FIG. 14. Curves of stomatal transpiration (ST), cuticular transpiration 



/ "R \ 

 (CT), total transpiration (T), and evaporation (-) for Diplazium, 



ST 

 together with the rates of relative stomatal transpiration ( ^ and 



p-rp \ E ' 



relative cuticular transpiration ( ^r) . 



