6 PLANTS, SEEDS, AND CURRENTS 



Sophora tomentosa (seeds). 



Suriana maritima (seed-like nucules). 



Thespesia populnea (seeds liberated by the decaying fruit). 

 Tournefortia gnaphalodes (pyrenes). 

 Vigna luteola (seeds). 



There are one or two trees typically represented in West Indian 

 beach-drift which ought to be mentioned, their fruits being carried 

 long distances by the currents, such as Terminalia katappa and Cassia 

 fistula. Both have been introduced from the Old World. The last 

 named is discussed at length on a later page. The first is dealt with 

 in my book on Plant Dispersal. It is a typical littoral tree of the 

 tropics in the eastern hemisphere ; and in the West Indies it is tend- 

 ing to escape from cultivation to find a home on the beach. 



Cirripedes, Serpulce, and similar organisms, that have attached 

 themselves to floating drift, often enable one to distinguish the larger 

 seeds that have been brought from a distance before being stranded. 

 Where the plants concerned grow in the neighbourhood it is not easy, 

 as before remarked, to discriminate between the foreign drift and the 

 drift of local origin. The difficulties are well exhibited in an island 

 like Jamaica. The large seeds of Entada scandens are common on 

 the beaches of the north coast; but the plant grows in the island, 

 and one cannot in the absence of incrusting shells of marine organ- 

 isms determine whether a weather-beaten seed lying on the beach 

 came originally from some neighbouring coast, such as from Cuba, 

 or whether it has acquired its weathered appearance from lying 

 exposed for a long period on the shore. On the other hand, the fruits 

 of Manicaria saccifera and Sacoglottis amazonica would be rightly 

 regarded as of foreign origin, since there is little probability of the 

 plants growing in the island. 



The Sorting Influence of the Waves. — The waves often sort 

 out the finer beach-drift, and deposit it in a line above the larger and 

 heavier fruits and seeds which are usually mixed up with Sargasso 

 weed, drift-wood, and similar materials. Small pumice pebbles and 

 Spirula shells mark the line of deposition of the smaller seeds and 

 fruits belonging to such plants as Hibiscus tiliaceus, Ipomcea pes- 

 caproB, Suriana maritima, Tournefortia gnaphalodes, Vigna luteola, 

 etc. It is, however, the larger drift that usually claims attention, 

 the smaller materials being often overlooked. 



From my observations at St. Croix, Turks Islands, Grenada, 

 Tobago, Trinidad, Jamaica, and Colon, it is evident that the beach- 

 drift displays much the same general characters over the West Indian 

 region. At the same time in addition to the seeds and fruits that 

 are found on most of the coasts, whether insular or continental, each 

 locality often presents some peculiar feature. Thus on the Colon 

 side of the Panama Isthmus there are to be found on the beaches the 

 large fruits of Prioria copaifera and empty palm fruits of Astrocaryum, 

 etc. In Jamaica we find the fruits of Grias cauliflora ; and in Trinidad 

 the ordinary seeds and fruits of the drift are often masked by the 

 large amount of strange fruits and seeds brought down by the Orinoco 

 and stranded on its south coast. 



