6 A MONTANE RAIN-FOREST. 



In spite of the fact that Jamaica was the first portion of the Western 

 Hemisphere to reach a high and valuable agricultural productivity, 

 there is still much of it that has been left untouched by the Spanish 

 and EngUsh occupants of the island, either because of its inaccessibiUty 

 or of the worthlessness of both the land and its natural covering. These 

 are the very localities which are most interesting to the botanist, 

 because of their being the places where the factors controlling plant 

 occurrence are operating in the most extreme degree. The higher 

 Blue Mountains, the limestone mountains of the central region, the 

 exsected hmestone region known as the "Cockpit Country," the coastal 

 deserts, the morasses and the mangrove swamps, as well as the algal 

 formations, are all calculated to interest the student of vegetation in 

 the highest degree. 



During three visits to Jamaica I have had opportunities to see some- 

 thing of all the above-mentioned formations, excepting the larger 

 morasses and the heart of the Cockpit Country, and have been able 

 to spend a total of eleven months in the Blue Mountain Region at 

 / Cinchona, the Tropical Station of the New York Botanical Garden. 

 Cinchona is situated on a spur projecting south from the Main Ridge 

 of the Blue Mountains, at an elevation of 5,000 feet (1,525 meters). 

 I first visited it in April 1903, in company^ with Dr. D. S. Johnson; 

 for the second time from October 1905 to May 1906, while holding the 

 Adam T. Bruce Fellowship in the Johns Hopkins University; and for 

 the third time from July to November 1909, while absent from the 

 Desert Laboratory. 



My last two visits to the Blue Mountains have been given to gaining 

 an acquaintance with the common and characteristic components of 

 its flora, to a study of the distribution of the vegetation within the 

 mountain region, and a study of the differences in physical conditions 

 which underlie the distinctness of the several habitats, as well as to 

 an investigation of some of the physiological activities of plants con- 

 fined to the rain-forest region. In the following pages I am presenting 

 my results on the general physiological plant geography of the Rain- 

 Forest Region, as well as my investigations on transpiration and growth 

 in typical rain-forest forms. 



I wish here to thank Dr. N. L. Britton, Director of the New York 

 Botanical Garden, for the facilities and equipment which were put at 

 my disposal in Jamaica by the Garden. To Dr. D. T. MacDougal 

 and Dr. D. S. Johnson I wish to express my thanks for their personal 

 interest in my work during both visits. I wish also to thank the Hon. 

 WiUiam Fawcett, former Director of Public Gardens and Plantations 

 of Jamaica, for many substantial kindnesses shown me during my 

 second visit in the island; and to William Harris, esq.. Superintendent 

 of Public Gardens and Plantations, my thanks are due for assistance 

 in taxonomic matters as well as for many services essential to the 

 prosecution of my work. 



