66, 



lose no water at all "but since a complete sealing 

 of the leaf is practically impossible, it may be assumed 

 that the recorded loss took place from the unsealed edges 

 of the leaf .At any rate, the result of prime interest here is 

 that the leaves lost the most v/ater when both surfaces were 

 open, From the lov/er surface alone the leaves lost 53,18^ 

 during the entire v/eek; while from the upper surface alone the 

 leaf lost only a total of 26,39^ during the v^hole week, It is 

 evident from these results that the leaves of this fern lose 

 water almost tv/ice as rapidly from their lower surface than 

 from the upper one, This appears rather a puzzling result for it 

 is actually this side that is exposed when the leaf curls up 

 in dry weather, while the side losing the least water is concealc-eL 

 and subject to very little desiceation • 



The results obtained from the second experiment axe 

 indicated in Tables V and VI, A study of the data reveals the 

 fact that when the leaves were subjected to artificial drying 

 in the sulphuric acid desiccator tliey behaved essentially 

 as they did in the calcium chloride desicc^tor.In other words, 

 although the leaves were dried by two different methods, the 

 results were the same; in both cases the greatest amoxxnt of v/ater 

 was lost from the lower surface of the leaf , This is true not only 

 for living leaves, but likewise for leases which had been 

 killed by chlorof orm,It is safe to conclude from these results 

 that the lower surface although covered with scales and 

 apparently r3v":tpnt to drought is really the surface which 



