OCEANIC DISPERSAL OF PLANTS. 309 



ON THE 



VEGETABLE DRIFT, AND ON THE DISPERSAL OF FRUITS AND SEEDS IN 



THE ISLANDS OF BOUGAINVILLE STRAITS, IN THE SOLOMON GROUP. 



Compiled from the Notes and Collections made by H. B. GUPPY, M.B., F.G.S., during 1883 and 1884, 



while Serving on Board H.M.S. "Lark." 



Just as we were on the point of finishing the examination of the collections of drift 

 seeds, &c, made by Mr Moseley and others, Dr H. B. Guppy, R.N., arrived in England 

 from the Solomon Islands, bringing with him considerable botanical collections, which he 

 has presented to Kew. Among other things is a quantity of drift seeds and seed-vessels, 

 and also others taken from the crops of carpophagous birds, shot by Lieutenant T. H. 

 Heming and Lieutenant A. Leeper of H.M.S. "Lark." As this collection affords addi- 

 tional evidence of the influence of oceanic currents and birds in the dissemination of 

 plants, a brief review of it follows, together with Dr Guppy 's observations made on the 

 spot, which he kindly communicated, with his permission and wish that any information 

 they contained might be embodied in this Report. The names of the plants are substi- 

 tuted for the numbers cited by Dr Guppy, and two or three other slight alterations have 

 been made. A list of the seeds and seed-vessels identified follows :— 



Vegetable Drift. — Lines of vegetable drift, intermingled with floating pumice, 

 are frequently observable whilst cruising among the islands of the Solomon group. 

 Amongst the floating fruits, those of Barringtonia speciosa and Calophyllum inophyllum 

 are commonly found ; and on more than one occasion, solitary fruits of the former were 

 noticed at sea at a distance of 130 to 150 miles to the southward of the group, being 

 probably derived from one of the islands of the New Hebrides to the eastward. Other 

 fruits occurring frequently in the drift are those of Nipa fruticans, and of two or more 

 species of Pandanus ; numerous beans (species of Mucuna, Canavalia, Dioclea), the long 

 germinated seedsof mangrove (Rhizophora), an occasional cocoa-nut, the cones oiCasuarina 

 equisetifolia, which is a common sea-shore tree, Terminalia spp., &c. On a small, bare, 

 sandy islet or sand-key situated on a reef in Bougainville Straits, I observed thirty 

 different kinds of seeds and fruits, which are only washed over the bank at spring tides. 

 These belong to characteristic littoral plants, such as Heritiera littoralis, Barringtonia 

 speciosa, Pandanus spp., Calophyllum inophyllum, Nipa fruticans, and Cocos nucifera. 



The Trees of a Coral Islet. — In order to connect my notes on the dispersal of plants in 

 this region, I will take the case of a small wooded islet, not more than a few hundred 

 yards across, and formed on a coral reef from materials heaped up by the waves to a 

 height of two or three feet above the usual high-tide level. On the weather margin of 



