CONCENTRATION OF TISSUE FLUIDS OF EPIPHYTES 49 1 



The determinations here recorded were secured in three periods of 

 field work, the first in Jamaica in 1915, the second and third in southern 

 Florida in 1916 and 1917. In the first period I had the advantage of 

 the co-operation of Mr. John V. Lawrence, who remained on the island 

 for some time longer than I was able to do, and to whom I am indebted 

 for a large part of the work on Jamaican forms. In the third period 

 Mr. Charles W. Crane rendered most efficient service in several phases 

 of the work. 



The determinations were carried out in the Tropical Laboratory at 

 Cinchona, Jamaica, and in the Subtropical Laboratory of the United 

 States Department of Agriculture at Miami, Florida. I have to thank 

 Mr. William Harris, F.L.S., and the members of the British Association 

 Committee for the use of the Laboratory at Cinchona, and am much 

 indebted to Dr. David Fairchild, Agricultural Explorer, and to Mr. 

 Edward Simmonds, in charge of the Plant Introduction Garden at 

 Miami, for the use of the laboratory and other favors. All the species 

 were determined in the herbarium of the New York Botanical Garden. 

 In addition, I am indebted to Dr. Small for various courtesies in the 

 field work. 



PRESENTATION OF DATA 



The following protocol gives the individual determinations for the 

 several species in terms of freezing point lowering, A , corrected for 

 undercooling, and osmotic concentration in atmospheres as determined 

 from a published table (Harris and Gortner, 1914). The averages, 

 designated by bars for each species, are given at the extreme right. 

 When only a single determination is available it has of necessity served 

 to represent the species in place of the average. 



In the Bromeliaceae an attempt has been made to arrange the forms 

 in a rough series from the most typical tank forms to those departing 

 most widely from the type in which water storage in the bases of the 

 leaves is possible. Ultimately I hope our determinations will cover a 

 range of forms sufficiently wide and be numerous enough to justify 

 consideration of the problem of the relationship between sap properties 

 and morphological structure in this fascinating family of plants. It 

 has not seemed feasible to attempt any logical classification of the 

 Orchidaceae, and they are merely alphabetically arranged for each of 

 the regions. 



All the Jamaican montane rain forest determinations were made in 

 1915. Hence the year is omitted when dates are cited. In the case of 



