10 PLANTS, SEEDS, AND CURRENTS 



tions of the same institution (Bot. Ser. 1907). A discussion of this 

 paper is given in Note 7 of the Appendix. I may remark that the 

 Florida " key " is the equivalent of the Bahamian " cay," and 

 that both terms will be employed here in their respective associations. 



The beach plants of the Turks Islands, which in the smaller cays 

 occupy much of their surface, are, as a rule, common West Indian 

 species and are generally distributed through the Bahamas, occurring 

 also in the Florida keys. 



The Stranded Drift of the Turks Islands. — The mangrove 

 formation, which is still fairly extensive in area on Grand Turk in 

 spite of the salt-making industry, is very limited in its composition, 

 and lacks most of the accessory plants that give variety to the great 

 mangrove formations of the large West Indian Islands. In its 

 restricted composition and in its constituent trees (Rhizophora mangle, 

 Laguncularia racemosa, Avicennia nitida, with Conocarpus erectus at 

 the borders) the mangrove belt of the islands of the Turks Group 

 approaches very closely that of the Florida Keys. So abundant is 

 the foreign drift on the beaches of the cays of the Turks Group that 

 the seeds and fruits of the local mangrove and beach plants scarcely 

 figure in it. Here we shall be concerned only with the larger stranded 

 seeds and fruits from other regions. The smaller and local drift is 

 discussed in Note 2 of the Appendix. 



During my sojourn of three months in the Turks Group I visited 

 all the islands or cays, and collected or recorded about 2000 foreign 

 seeds or fruits, all of them doubtless derived from the islands to the 

 southward and eastward, San Domingo, Porto Rico, and the Leeward 

 Islands. In Note 13 of the Appendix it is shown from the indica- 

 tions of bottle-drift stranded on the south-eastern Bahamas, and from 

 the course taken by bottles dropped into the sea in this neighbour- 

 hood, that the prevailing set of the surface currents in this region 

 is in a W.N.W. direction, and that the Turks Group lies in the track 

 of drift on its way in the Antillean Stream from the islands to the 

 eastward and southward to the Florida Straits, where it gets within 

 the influence of the Gulf Stream. 



The analysis given below illustrates the relative frequency of the 

 several kinds of seeds and fruits that figure in the beach-drift. As 

 above remarked the local seed-drift is derived from plants growing 

 in the vicinity, whether in the mangrove swamps or on the sandy 

 beaches, the present discussion being almost exclusively restricted 

 to the seeds and fruits of plants not growing on the islands, the local 

 materials being largely disguised by the mass of drift from a distance. 



There are, however, named in this list the seeds of Guilandina 

 bonducella, which grows in the larger islands of the Turks Group away 

 from the beach. But since these drift seeds were best represented 

 on Greater Sand Cay at the southern end of the group, a cay which 

 does not possess the parent plant but is the first to receive the foreign 

 drift, it is apparent that they must be included in the list. 



Some of the drift is washed into the interior of the cays during 

 hurricanes, and may be found between the sand-hills a hundred 

 yards and more from the beach. It will be noticed in the following 

 table that more than half of the foreign seeds and fruits stranded 



