BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 29, pp. 649-656 DECEMBER 30, 1918 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



BEARING OF THE DISTRIBUTION OF THE EXISTING FLORA 



OF CENTRAL AMERICA AND THE ANTILLES ON 



FORMER LAND CONNECTIONS - 



BY WILLIAM TRE LEASE 



{Read before the Paleontological Society December 31, 1917) 



CONTENTS 



Page 



Break in West Indian flora between Saint Croix and Saint Thomas 649 



Quercus suggests lack of land connection with North America 650 



Nolineae and Yucceae indicate absence of continental land connection 651 



Phoradendron and Furcrwa suggest land connection with North and South 



America 652 



Agave indicates relationship to a successively fragmented Antillean bridge 



or spur extending southeastward from Yucatan 653 



References 656 



Break in West Indian Flora between Saint Croix and 

 Saint Thomas 



Apart from weeds of various origin and occurrence, the West Indian 

 flora is an intricate blending of plants identical with or closely related to 

 those of South America on the one hand and of North America on the 

 other hand, with a relatively small proportion of true endemism of types. 

 The chain of islands has been held for a ^^province'^ of the Tropical Amer- 

 ican floral region, correlated with the tropical Mexican province of Nortli 

 America and the subequatorial Andine and cisequatorial Savanna prov- 

 inces of South America and contiguous Central America. 



The flora of Trinidad and other islands close to the South American 

 coast is essentially a South American flora except for obvious introduc- 

 tions. The flora of tlie Bahamas may be said to have contributed char- 

 acteristic elements to subtropical Florida, rather than to be a temperate 

 North American flora, and it appears to be largely of Cuban derivation. 



A number of years since. Baron Eggers^ showed that a considerable 



* Manuscript received by the Secretary of the Society August 22, 1918. 

 For references, see page 656. 



XLVIII — Bull. Geol. Soc. Am., Vol. 29, 1917 (649) 



