84. 



11, The leaf under dry conditions loses the greater amount 



of water from its lower surface with the surprising result 

 that a curling of the leaf occurs, which leaves the lower 

 epidermis exposed and the- upper epidermis concealed on the 

 inside, 

 12, The curling of the leaf is perhaps due to the unequal 



loss of v;ater from the cells of the upper and lower! lev, ,:.r 

 epidermis, 

 13, The curling of the living leaf is apparently the result 

 of osmotic phenomena; the expanding is entirely due to 

 imbibition in dead leaves and to both osmosis and imbibition 

 in the living ones, 

 14, The function of the scales is J ": probably to facilitate 



an equal and gradual distribution of water thrbughout the Ir-^*^ 

 surface of the leaf after a rain and als o to absorb v/ater, 

 that is present on the surface of the leaf , and to pass it 

 to the internal tissues of the leaf. 

 15, The scales originate from epidermal cells near the growing 

 point of each pinna, 



16,1:10 raycorrhizal fungus ?/as seen in the roots of this 

 fern, 



I desire to express my indebtedness and gratitude 

 to Professor Duncan S.Jolinson for much helpful advice and 

 encouragement reql'qved during the progress of the 7/ork 

 and tc express my sincere thanks to Professor Burton E, Livingston 

 for helpful suggestions and for the loan of atmometers to 

 carry on this work. 



