396 Trans. Acad. Sci. of St. Louis. 



united with Honduras, Cuba with Florida and also with South 

 America, through the Windward Islands. There would be a 

 narrow channel between Cuba and Yucatan, between Jamaica 

 and Haiti, and a wide and deep channel between Jamaica and 



Cuba." 



Florida and the Bahamas, with their submarine banks, are 

 all of recent formation from the calcareous deposit of the 

 warm waters of the Gulf Stream, and are still growing. 

 From this we may deduce that at one time the United States 

 and Cuba were not connected through Florida and the Ba- 

 hamas, because these connections did not exist. Then we 

 would have Cuba connected with Yucatan and Honduras only, 

 and thereby account for the neotropic origin of the Cuban 

 flora. 



The Greater Antilles are all of an old formation, and the 

 presence of such a great number of endemic species of phae- 

 no^ams would indicate that they were separated from the 

 maiuland at an early date, thus giving isolation and the time 

 necessary for the evolution of the plants peculiar to them. 

 Cuba, being the greatest, would have a natural right to the 

 greatest number of these peculiar forms. 



The geographical means of distribution are important fac- 

 tors in tracing the origin of the Cuban flora. The Gulf 

 Stream, washing the coast of northern South America, is 

 deflected from the coast of Central America into the Caribbean 

 Sea, carrying all tropical seeds that it may have gathered from 

 the shores of South and Central America, over into the West 

 Indies. Cuba's great coast liue and its proximity to the 

 stream, a part of which flows down along the south coast, 

 losing itself in the Lesser Antilles, while the main part flows 

 north, making a circuit of the Gulf of Mexico, and back 

 toward the south, striking the north coast of Cuba, would 

 »reatly favor the reception of such seeds. The Gulf Stream 

 in this way not only establishes neotropic plants in Cuba, but 

 materially prevents the entrance of plants from Florida. 



All the prevailing winds in this region are from the south 

 except an occasional norther, whose distributing influence is 

 more than counteracted by the Gulf Stream. Even should 

 these northers succeed in driving seeds across from Florida, 



