Seed- Scattering 259 



themselves transported from place to place; but it will 

 ^encTally be found that these arc seeds which have 

 been altered by cultivation. The i^rain of wheat 

 and rye, for instance, falls quite naked from the ear 

 as soon as it is ripe, and sinks at once in water; and 

 this is one reason why neither is ever found wild. Rice 

 is a little better off, for each grain is enclosed in a 

 rough, hard case, which effectually preserves it from 

 injury, and probably in its natural state it was able 

 to float on water. But now that its size and weight 

 have been increased by cultivation, it sinks like the 

 others. 



Many bean-like and pea-like seeds stand immer- 

 sion extremely well, and some of these, conveyed 

 3,000 miles or so by the Gulf Stream and cast upon 

 the Azores and on the Orkney islands, have been suc- 

 cessfully grown at Kew Gardens, though they could 

 not establish themselves in either group of islands 

 owing to the unsuitable climate of both. 



Among the islands which have been especially in- 

 debted to ocean-currents for their vegetation, may be 

 mentioned the Bermudas, more than half of whose 

 flowering plants are supposed to be colonists. The 

 greater number of these belong to the tropics and 

 West Indies, and have been to a large extent brought 

 by the Gulf Stream, which is constantly throwing up 

 various objects on the shore — the seeds of trees among 

 the rest. The soapberry-tree, for instance, has been 

 observed to spring up in this way, from seeds thus cast 

 ashore. 



Seeds may occasionally chance to be conveyed 

 across the ocean in drift-wood, without ever coming 

 in contact with the water at all ; for stones and small 



