THE FLORA OF THE AMERICAN VIRGIN ISLANDS 



N. L. BRITTON 

 New York Botanical Garden 



The islands St. Thomas, St. Jan and St. Croix recently purchased 

 by the United States from the kingdom of Denmark, are situated to the 

 east and southeast of the island of Porto Rico. My interest in their 

 flora was first aroused by the proximity of the Virgin Islands archi- 

 pelago to Porto Rico, both the Porto Rican islands Culebra and 

 Vieques being parts of the archipelago. I therefore took occasion in 

 1913, accompanied by Dr. J. N. Rose and with the help of Mrs. 

 Britton, Miss Delia W. Marble, and Dr. J. A. Shafer, to explore St. 

 Thomas and St. Jan quite thoroughly, and Dr. Rose made collections 

 on St. Croix, while we were engaged in studying the cacti of the West 

 Indies.^ In 1901, I had made a brief visit to St. Croix, with Mr. 

 John F. Cowell.2 



The islands are all hilly, there being very little level land on either 

 St. Thomas or St. Jan, but more on St. Croix. The rocks are mostly 

 of plutonic origin, but there is some limestone on St. Croix and locally 

 other stratified rocks occur. The highest elevation is about 500 

 meters (1,550 feet), on The Crown of St. Thomas. 



There is but little natural forest remaining on any of the islands, 

 and what there is is confined to the hilltops in a few places. Re- 

 forestation is the crying need of the new possession, and it will be 

 highly discreditable to the United States if this subject is not im- 

 mediately taken in hand. Most of the higher parts of all three islands 

 are not available for any but forest products and the supply of wood 

 for fuel needs to be increased and the rainfall conserved by a forest 

 cover, for most of the rain now runs off immediately. This destruc- 

 tion of the forest has doubtless eliminated a good many species from 

 the original flora of the islands. 



The principal literature of the botany of the islands is as follows •? 



H. West. "Bidrag til Beskrivelse over Ste Croix, nied en kort udsigt over St. 

 Thomas, St. Jean, Tortola, Spanishtown og Crabeneiland." Kiobenhavn. 

 Pp- 363. 1793. [German edition pp. 274, Copenhagen 1794.] 



West enumerates and partly describes 542 species, of which 11 1 were culti- 



* Jour. N. Y. Bot. Card. 14: 99-109. 

 2 Jour. N. Y. Bot. Card. 2: 166. 



^ See also citations in the chapters on Hepaticae, Fungi and Algae. 



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