587 A. EK. Verrill—The Bermuda Islands. 17 
Or 
Drop-seed Grass. (Sporobolus Virginicus Kunth.) 
A common grass on the sand-dunes; one of the important sand- 
binding plants. 
Sea-side Club-moss. (Psilotwm triquetrum Sw.) 
The only native lycopodiaceous plant on the islands. It grows 
among rocks near the shore at Walsingham and Ireland Island ; not 
common. 
Widely distributed on the tropical coasts of both hemispheres. 
d.— Origin of the Native Flora. 
All the native plants, except about eight that seem to be endemic, 
were originally native either of Northeastern America or of the West 
Indies and the Southeastern United States, from whence they were 
introduced by natural agencies prior to the advent of man. Migra- 
tory birds have probably always been the chief agencies for these 
introductions of plants, especially of those from Northeastern Amer- 
ica, for large numbers of birds fly from New England and Nova 
Scotia directly to the Bermudas every year in their autumnal migra- 
tions. They can, therefore, readily convey hard, indigestible seeds 
in their digestive organs for the brief period that this journey 
would require, for at the common rate of 40 miles an hour, it 
would require less than 20 hours to make the trip. Small seeds of 
many kinds may be carried adhering to the feathers, or contained in 
mud adhering to the feet of aquatic birds. 
During the spring migrations seeds could be brought from the 
West Indies in the same ways, though the distance is somewhat 
greater. 
No doubt seeds of numerous species are thus annually carried in 
these ways from New England and Nova Scotia to the Bermudas, 
but of these only a very small fraction would be likely to fall in 
places suitable for their germination, and of those that might ger- 
minate, very few would find the soil and climate suitable for per- 
manent growth. Some might be able to live for several favorable 
seasons, and then be exterminated by a season of unusual drouth, 
just as is the case with many plants intentionally planted. Very 
few of our northern hard wood trees and fruit-bearing shrubs will 
grow in Bermuda. 
Although it is probable that fewer seeds are brought from the 
West Indies by birds, the climate and other conditions are much 
