18 FLORA OF ST. CROIX .AND THE VIRGIN ISLANDS. 



theory drawn from the facts observed in regard to the mutual relation 

 between St. Croix and the Yirgin Islands, that geological revolutions 

 have been equally or perhaps even more powerfully influential in arrang- 

 ing the distribution of species than the greater or smaller distance, and 

 the similarity of physical conditions. 



A full knowledge of these interesting facts can, however, not be ex- 

 pected till a more thorough exploration of all the West India islands 

 has taken place. Few of them are as yet tolerably well known, and it is 

 therefore earnestly to be hoped that such an exploration of all the West 

 Indies may soon be effected, the result of which will no doubt be of 

 the highest importance both to botany and to all other branches of 

 natural science. 



It generally requires the accumulated study and knowledge of gener- 

 ations before the less palpable and more delicate, but often most impor- 

 tant, facts in natural history can be explained : the West Indies have 

 been comparatively well studied since the middle of the last century; 

 and it would seem well now to follow up the work in order to complete 

 a thorough investigation, which might be used as a basis for the ex- 

 planation of similar facts observed in other and less well known parts 

 of the world. 



The flora of the Virgin Islands and St. Croix has been studied by 

 several botanists, some of whom have published the results of their re- 

 search, which has, however, among the former group, been chiefly con- 

 fined to the Danish islands, the English and particularly the Spanish 

 ones having as yet been only imperfectly explored. 



Publications on the flora of these islands are given by West in his 

 Description of St. Croix (Copenhagen, 1793); Schlechtendal, Florula 

 Ins. St. Thoma3, in Linnsea, 1828-31 and 1834; and Eggers, Flora of St. 

 Croix, in the Vidensk. Medd. fra Naturhist. Forening (Copenhagen, 1876) 

 besides minor contributions in Vahl's Eclogre Americans, Symbols Bo- 

 tanicae, and Enumeratio Plantarum, Krebs in Xaturh. Tidsskrift, 1817, 

 on the flora of St. Thomas, De Candolle's Prodromus, and Grisebach's 

 Flora of the British West India Islands. This latter work, no doubt 

 from want of material, scarcely ever mentions the British Virgin Islands. 



Collections of plants from the islands in question are found chiefly in 

 the Museum of the Botanical Garden in Copenhagen, as well as scat- 

 tered in other European herbaria, collected principally by v. llohr, West, 

 Dr. Ryan, Ledru, Eiedle, L'Herminier in the past century, by Benzon, 

 Wahlmann, Ehrenberg, Dr. Eavn, Dr. Hornbeck, Duchassaing, Schoin- 

 burgk, Plee, Wydler, Orsted, Krebs, and Eggers in the present. 



