WEST INDIAN BEACH-DRIFT 



17 



Crescentia cucurbitina. Prof. Harshberger, who visited this, locality, 

 refers to the Bucida and Grias trees (Phyt. Surv. N. A?ner>, p. 678). 

 The " olive tree," as the Jamaicans name Bucida buceras, iia charac- 

 teristic swamp tree of the estuaries on the north side of the island. 

 Owing to the lack of mature fruits the opportunity of studying this 

 interesting tree from the standpoint of dispersal was not presented 

 to me. 



Comparison of the Beach-drift on the Pacific and West 

 Indian Coasts of Tropical America. — A few remarks may here 

 be made on the small contrast that exists between the beach-drift 

 on the Pacific coasts of tropical America and on the West Indian 

 or Caribbean side. As discussed in the case of the Ecuadorian and 

 Panama beach-drift in my book on Plant Dispersal (p. 498), many of 

 the familiar mangrove and beach plants occur on both sides of the 

 continent and add their fruits and seeds to the drift, such as Rhizo- 

 phora mangle, Laguncularia racemosa, Avicennia nitida, Canavalia 

 obtusifolia, Conocarpus erectus, Ecastaphyllum brownei, Hibiscus 

 tiliaceus, Hippomane mancinella, Ipomcea pes-caprae, etc. To these 

 may now be added Sccevola plumieri, a characteristic West Indian 

 strand shrub that occurs also on the Pacific coasts. 



Equally common on the beaches of the West Indies and Colon on 

 the Atlantic side and of Ecuador and Panama on the Pacific side 

 are the seeds of Entada scandens and Mucuna urens and the fibrous 

 " stones " of Spondias lutea. Much of the drift found afloat in the 

 estuaries on the Pacific coast could be matched in those of the West 

 Indian region, since many of the estuarine and swamp plants are the 

 same. If we supplement the account given in my previous work of 

 the drift carried down to the sea by the Guayaquil River in Ecuador 

 with the names of two floating fruits not there identified, namely, 

 the gourds of Crescentia cujete and the fruits of Grias cauliflora, we 

 emphasise the resemblance between the character of the drift carried 

 into the Pacific Ocean by the Ecuadorian rivers and of that dis- 

 charged into the Caribbean Sea by the Black River in Jamaica. 

 Amongst the beach-drift gathered by me on both sides of the Panama 

 Isthmus were the large pods of Prioria copaifera, as identified at 

 Kew. They seem to be quite useless for dispersal by currents, 

 since the seeds of the fruits examined were always decayed. This is 

 the type species of a genus which was first described by Grisebach 

 (p. 215) from a rare Jamaican tree. 



There are, however, differences between the drift found on the 

 Pacific and Atlantic sides. Thus since neither Manicaria saccifera 

 nor Sacoglottis amazonica occur on the Pacific border of the conti- 

 nent, their fruits have not been found in the drift. Here the empty 

 seeds of the Vegetable Ivory palm, Phytelephas macrocarpa, con- 

 stitute one of the principal features of the floating and stranded drift 

 of coasts and estuaries in Ecuador, the sound seeds possessing no 

 floating power. It is remarkable that this palm which abounds on 

 the banks of the Magdalena River does not contribute to West Indian 

 drift. We learn from Spruce's Notes of a Botanist on the Amazon 

 and in the Andes that the Eastern and Western Andes possess in each 

 case a separate species of the genus, 

 c 



