FOREIGN DRIFT OF THE TURKS ISLANDS 119 



the back of St. Anne's. In the Pacific Islands it is a characteristic 

 plant on the trees lining the beaches and the estuaries. 



Two critical facts present themselves in the New World with 

 reference to the distribution of this plant over the warm region of 

 the globe. In the first place there is its occurrence on both the 

 Atlantic and Pacific borders of Central America. As I pointed out 

 in my work on Plant Dispersal, this does not compel us to assume, 

 as in the case of the mangrove flora, that the plant's present distribu- 

 tion in the New World antedates the emergence of the Panama 

 Isthmus. Frequenting, as it does, not only estuarine regions but 

 also mountain woods inland, it can be at once perceived that, given 

 its occurrence in the interior of a region like the Isthmus of Panama, 

 the seeds of plants growing on the same " divide " could be carried 

 by rivers to both the Atlantic and Pacific borders. The seeds are 

 often found in river-drift in different parts of the world. Thus I 

 found them not only in estuaries on both sides of the Panama Isthmus, 

 but also in the Guayaquil River in Ecuador, and in the estuaries 

 of Fiji. 



The second critical fact of distribution is that whilst Entada 

 scandens grows on the West Coast of tropical Africa, it is absent from 

 the corresponding portions of South America (Venezuela to Brazil) 

 and from the neighbouring West Indian islands, such as Trinidad 

 and Tobago. It is certainly strange that seeds, which are trans- 

 ported in the Gulf Stream drift to Europe in a sound state, have 

 not been carried by the Main Equatorial Current from the Gulf of 

 Guinea' to the South American mainland. As described in Chapter III., 

 this is the direct track of many of the bottles thrown overboard in 

 this current in mid-Atlantic. Whilst a West Indian seed would 

 require a year or more to reach the coasts of Europe, it would accom- 

 plish the passage from West Africa to Brazil in the Main Equatorial 

 Current in from two to three months. A great deal, of course, 

 depends on the distribution of the plant on the African coast. If it 

 does not grow much south of Senegal and the Gambia, its seeds would 

 be carried across the Atlantic in the North Equatorial Current, 

 and would not strike the South American mainland. It is pointed 

 out in Chapter III that bottle-drift from the latitude of Cape Verde 

 only reaches the Lesser Antilles and the islands north; and it is 

 not improbable that we have here an explanation of the peculiar 

 distribution of Entada scandens in the New World. In other words, 

 its range in tropical America may prove to be determined through 

 the arrangement of the equatorial currents by its distribution in 

 tropical West Africa. 



It may be that Entada scandens has not been for many ages a 

 denizen of the New World. So little does it figure in the floras of 

 the larger West Indian islands that the American botanical explorers, 

 so freely quoted in Harshberger's great work, rarely seem to have 

 recorded it. Yet it probably occurs in all these large islands. It is 

 almost certain that the numbers of these seeds thrown up on the 

 beaches of the Turks Islands are derived from Hispaniola, Porto 

 Rico, and the northern islands of the Lesser Antilles, since the 

 plant is not represented either in the drift or in the floras of the 



