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cut stem was in this way made good, the leaves so 

 treated remaining fresh and bright for 24 hours. It is 

 not improbable but that an equal amount would be ab- 

 sorbed by an ordinary leaf without filz under the same 

 circumstances, as the evaporation from the under surface 

 was suspended by the leaf resting on the water. Other 

 considerations beside the anatomical structure indicate 

 that this is not the chief function of the filz. Owing to 

 the height to which the tree usually grows the leaves 

 are not likely to acquire much water by the formation 

 of dew : the upper leaf surface is peculiarly adapted to 

 shed rain; the only opportunity for the leaf to acquire 

 water is by means of the wind turning the surface so 

 the raindrops would strike the under side. 



The hair of Vitis is very similar to that of Populus, 

 but the filz is not nearly so thick. The stomata are 

 raised. The silvery luster on placing the leaf in water 

 does not disappear so readily. The leaf was very 

 thoroughly tested and its ability to take up water is 

 even less than that of Populus. Leaves placed with 

 their under surface on water did not absorb enough to 

 keep them fresh, although they were by no means so 

 wilted as those left for the same time without water. 

 Some were tried by placing the upper only, on water, 

 the under one exposed to the air. These also absorbed 

 a very little, so that the condition of the leaf was about 

 the same as when the under surface was wet. Some were 

 first allowed to wilt, and then were brushed, dipped and 

 immersed but all to no purpose. These were examined 

 in the middle of July, at a time when we would expect 

 the life forces all to be in action. 



The leaf of Rubus Idaeus L. is covered by a thin 



