﻿604 Gilbert : Revision of the Bermuda Ferns 



these species and of the countries where they are known to be in- 

 digenous shows that I 5 belong to the West Indies, 3 to the con- 

 tinent of North America, 2 to Europe and I to the Azores ; while 

 4 are endemic, being the product of Bermuda alone. Thus it is 

 evident that the presence of a great majority of the species can be 

 accounted for by transmission on the waves or winds from com- 

 paratively nearby sources. Even the Azorean form of Asplcmum 

 Tridwmaiics may well be regarded as a development of that species 

 resulting from insular conditions in both cases. Adiantum Capillus- 

 Veneris and Dryopteris acideata are really denizens of the world 

 and liable to be found almost anywhere. There remain the four 

 distinctive species and variety belonging to Bermuda alone ; and I 

 leave it for the speculative botanist to determine whether these are 

 the results of evolution, or whether they are the remains of a flora 

 that existed in an earlier geological period when a much greater 

 land surface existed where the Bermudas now lie, and of which 

 they formed the central and most elevated portion. 



There is a curious relation between the fern flora of Bermuda 

 and that of Juan Fernandez. The latter is 18 miles long and 6 

 miles broad, with mountains 3,000 ft. high. Thus while it is not 

 so long as Bermuda, it is so much wider that the superficial area 

 must be somewhat greater, while the high elevation of the land af- 

 fords a much greater variety of climatic conditions. Their distance 

 from the equator is approximately the same, Bermuda being 

 3 2° 15' N. and Juan Fernandez 33 37' S. But while Bermuda is 

 600 miles from the coast of North America, Tuan Fernandez is only 

 400 miles from the coast of South America. Alfred Russell Wal- 

 lace informs us that there are 24 species of ferns in Juan Fernandez 

 and that 4 of these are " quite peculiar," by which he means that 

 they are endemic. This lacks only one of the same number of 

 species as are found in Bermuda, and what is still more curious, 

 there is exactly the same number of endemic species. Mr. Wallace 

 declares that the latter fact indicates " the remote period when Juan 

 Fernandez first received its vegetation." If the same reasoning be 

 applied to Bermuda, we shall be led to infer that a portion of the 

 main island at least is of very ancient origin, and that the peculiar 

 species are survivals rather than developments. 



