THE BOTANY OF ANTIGUA 43 



average yearly rainfall of 130 inches, certain points having nearly 

 300 inches in the year. 



There is no rainy season in Antigua, though, as a rule, the 

 months from September to December are wetter than the early 

 months of the year. Droughts are of frequent occurrence, and 

 are sometimes very severe ; while the rains, when they do come, 

 are often very local, one estate getting 3 or 4 inches while 

 another a few miles away gets little or none. 



The early months of the year are cooler than the later months ; 

 but this is due more to the greater powder of the Trade Wind than 

 to differences of temperature. 



There are no seasonal changes in plants as there are in England, 

 or in tropical countries like India where one season is regularly 

 wet and another regularly dry. During the dry weather the 

 plants adopt a xerophytic habit; leaves drop off, flower buds 

 remain unopened, and seeds lie dormant in the ground. But 

 should a few inches of rain fall after weeks of dryness, no matter 

 what the time of year, all the seedlings sprout vigorously, the 

 trees are covered again in sheen, the activity of the quiescent 

 cambium is renowned, and great bursts of glorious flowering occur 

 on such trees as the Flamboyant {Poinciana regict) Tamarind 

 [Tamarindus indica) and Scarlet Cordia. It follows that terminal 

 bud-scars and "annual" rings have no significance as registers of 

 the age of a tree, but merely indicate the number of droughts and 

 intervening spells of wet weather. 



Owing to the smallness and irregularity of the rainfall, the 

 w^hole vegetation partakes of a xerophytic character. This is the 

 more marked as there are no large springs in the island and no 

 streams worthy of the name. Many parts of the island have a large 

 amount of sodium chloride, so that water drawn from them shows 

 an amount of chlorine greatly above the average ; thus at two 

 stations in the Central Plain the sodium chloride content was 

 considerably over 1000 parts per 100,000. This also tends to 

 produce xerophytic characters in the flora, especially in the 

 Central Plain. 



The geographical configuration of the island, with the mountains 

 in the south-west, causes more rain to fall in that part than in 

 the north and east. The rain drains quickly off the steep moun- 

 tains and gives a fair supply to the valleys between them, such as 

 Christian Valley and Blubber Valley. 



c. Geological. — The geology of Antigua is very interesting, and 

 has called forth various theories of very divers natures ; and the 

 relations of the difierent formations to one another cannot yet be 

 considered as settled. All geologists, however, are agreed that 

 Antigua consists of three distinct formations which occupy 

 respectively the north-east, south-w^est, and centre of the island, 

 their boundaries running approximately from north-w^est to 

 south-east. 



The northern formation is a limestone which is usually 

 considered to belong to the Oligocene. It corresponds with the 

 limestone of which Barbuda, the eastern half of Guadaloupe, 



