INTRODUCTION. 



The vegetation of Jamaica is of particular interest, both by reason 

 of the wealth of the flora of which it is made up and because of the 

 diversity which is given it by the varied geological, topographic, and 

 climatic conditions which exist within the limits of so small an island. 

 Jamaica lies in the center of the Caribbean Sea in 18 N. latitude, is 

 about 150 miles long, and from 25 to 50 miles wide. Its most salient 

 physical feature is the central mountainous axis, the eastern end of 

 which is lofty and of relatively recent geologic age, while the western 

 two-thirds are lower and older; the recent formations being mostly 

 shales, conglomerates, and tuffs, the older limestone. The mountain- 

 ous interior is bordered on the north by a very narrow coastal plain, 

 on the south by a plain which is narrow opposite the loftier mountain 

 mass, but wide in the southwestern parishes of the island. The higher 

 elevations of the eastern end constitute the Blue Mountain Range, 

 which attains to an altitude of 7,428 feet (2,264 meters). Not only 

 do the Blue Mountains present conditions of temperature that result 

 in their own vegetation being distinct from that of the lowlands, but 

 they moreover serve as a barrier to the trade winds, and thereby give 

 differences of rainfall and humidity on their north and south sides which 

 are of importance in determining the character of the lowland vegeta- 

 tion. The greatest rainfall in the island is registered at high elevations 

 on the northern slopes of the Blue Mountains, while the least occurs at 

 the coast to the south of them. The lower and older portion of the 

 mountainous axis, which reaches its highest points in Mount Diablo, 

 Bull Head, Dolphin Head, and the Santa Cruz Mountains, is much less 

 diversified than the Blue Mountains in both temperature and rainfall 

 conditions, and strikingly dissimilar to any part of them in its vegetation. 

 South of the older mountainous region are broad savannas, with morasses 

 along the larger streams and deserts on certain parts of the coast. 



There is perhaps no tropical area of its size in the world that has 

 received more painstaking and prolonged attention at the hands of 

 collectors and taxonomists than has Jamaica. From the reconnais- 

 sances of Sir Hans Sloane, the first botanical visitor to the island, in 

 1687, down to the methodical campaign which has been made during 

 the last twenty years against all the less-known parts of the island, 

 there has been a steady stream of additions to the flora, in which over 

 forty botanists have taken a hand. During these two centuries of 

 floristic activity there has been, however, but a single visitor interested 

 in the vegetation of the island in its physiognomic and physiological 

 aspects, the Danish botanist Orsted. He visited the island in 1846 

 and published a paper entitled "Skildring af Naturen paa Jamaica," 

 which is a brief description of the vegetation, strikingly modern in its 

 manner and as accurate as his brief visit of six weeks would permit. 



