24 A NATURALIST ON THE "CHALLENGER." 



I have referred to the falling in of the roofs of caves. At 

 the mouths of nearly all the caves are hollows with steep rocky 

 sides, produced by the falling in of former extensions of the 

 caves. One of the largest of these is at the mouth of Paynter's 

 Vale Cave. This hollow is sheltered from the sun by its steep 

 walls, and is hence constantly shady and moist. It is a natural 

 fernery, fifteen species of ferns being found within its small 

 compass, two of them occurring nowhere else in the islands. 

 Wild coffee trees thrive amongst the ferns in the hollow. The 

 plants of Bermuda, which are of West Indian origin, were 

 transported thither, probably, as Grisebach* states, by the Gulf 

 Stream, or general drift of heated surface water in this direction. 

 Others may have travelled with the cyclones which pass con- 

 stantly from the West Indies in the direction of Bermuda, and 

 sometimes reach the island. There are no winds blowing 

 directly from the American coast which would be likely to 

 carry seeds, the anticyclones taking a different direction. It is, 

 however, probable that the occurrence of American plants in the 

 islands is connected with the fact that the islands are visited 

 from time to time by immense numbers of migratory birds from 

 that continent, especially during their great southern migration. 



Of these the American Golden Plover (Charadriiis marmoratus) 

 seems to visit Bermuda in the greatest numbers, but various 

 other birds, frequenting marshes, Gallinules, Rails and Snipes, 

 arrive in no small quantities every year. These birds have 

 probably brought a good many plants to Bermuda, as seeds 

 attached to their feet or feathers, or in their crops. The seed 

 used for the onion crops in Bermuda is all imported yearly, 

 mostly from Madeira, and the potato seed is brought from the 

 United States. Various seeds cannot fail to reach the island 

 with these imports, and the constant importation of hay must 

 have led to the introduction of many more. 



Shipwrecks furnish additions to the flora occasionally. A 

 vessel laden with grapes was wrecked on the coast a short time 

 ago. The boxes of grapes were washed ashore, and the grape 

 seeds germinated in abundance, so that Sir J. H. Lefroy was 

 able to gather a number of small plants for his garden. 



* A. Grisebach, "Die Vegetation der Erde." Leipzig, 1872. 2te 

 Bd. II, s. 454. 



