136 DISSEMINATION OF SEEDS. 



carried by the wind over long distances and, if dropped 

 into the sea, may reach land by means of surface currents. 

 The grasses are mostly wind-fertilized and can therefore 

 establish themselves in any place whose climate and soil 

 are adapted to the germination of the seeds and to the 

 growth of the plants. 



Heavy seeds and dry fruits, especially if inclosed in a 

 hard shell, may be exposed for a long time to sea-water 

 without injury to their vitality; they may be conveyed 

 across the sea for long distances by winds and surface- 

 currents. Double cocoa-nuts cross the Indian Ocean from 

 the Se} r chelle Islands to the coast of Sumatra. West 

 Indian beans frequently reach the west coast of Scotland. 

 "Large seeds which have floated from Madagascar and 

 Mauritius, around the Cape of Good Hope, have been 

 thrown on the shores of St. Helena and have there some- 

 times germinated." 



When once established in climate and soil adapted to 

 their habits and constitution, plants soon take possession 

 of a country, often extirpating the native plants. The 

 cocoa planted on a coral island becomes the progenitor 

 of a flourishing grove of cocoa palms. This is the case 

 on islands of the Pacific whither the seeds have been 

 carried by ocean currents. 



The Gulf Stream aids greatly in this work. By its 

 aid the seeds of West Indian plants are carried annually 

 to the shores of Ireland, Scotland, and Nova Zembla. 

 To Bermuda the currents carry objects, animate and in- 

 animate, and almost without number from the Caribbean 

 Sea. These include the seeds of shrubs and trees and of 

 tender plants ; they are frequently cast ashore and germi- 

 nate. Plants on the coast of Brazil and Guiana are 

 identical with those on the banks of the Congo and, as 

 the seeds of those plants are capable of resisting the 



