MISCELLANEOUS PLANTS 



247 



on its fitness for dispersal by this agency was made in the Solomon 

 Islands in 1883. Since that time I have tested the capacity in the 

 Keeling Islands, in Hawaii, Fiji, and other localities {Solomon 

 Islands, 1887, p. 305; Journ. Vict. Inst. London, 1889; Plant 

 Dispersal, 1906, p. 531), all the experiments giving the same indica- 

 tions and culminating in one where, after floating a year in sea- water, 

 a seed germinated and developed into a plant. The dried fruits, 

 which lie in numbers under the trees, are, as already observed, very 

 likely to be swept off the beach by the waves. They float, but in 

 time break down, thus liberating the buoyant seeds on which the 

 dispersal by currents eventually depends. In the West Indies the 

 dried fruits, seeds, and seedlings produced from stranded seeds are 

 characteristic of the beach-drift, and the same may be said of the 

 Hawaiian Islands. In the Solomon Group I found that this was 

 one of the early plants that established themselves on the low sandy 

 islets of the coral reefs (Chall. Bot., IV., 309). In the Marquesas, 

 according to Jouan, it is only found on the seashores in places to 

 which the waves could have conveyed the seeds (Ibid., IV., 125). 

 In my Victoria Institute paper above quoted good reasons are given 

 for the belief that the Keeling Islands possessed the tree at the 

 time of their first occupation by white men about 1825, and that 

 they received it with many other of their shore plants through the 

 instrumentality of the currents. 



The indications of the foregoing discussion are that whilst, as 

 with Hibiscus tiliaceus, man and the currents have each played their 

 part in distributing the species, the currents have perhaps had a 

 rather more important share in the process than in the case of 

 Hibiscus tiliaceus. However, I hope at some future time to discuss 

 the distribution and dispersal of Thespesia populnea in greater 

 detail. 



ToURNEFORTIA GNAPHALODES, R. Br., and TOURNEFORTIA ARGENTEA, 



Linn. f. 



The distribution of these widely spread littoral species of Tourne- 

 fortia raises several of the questions presented by the two shore 

 species of Sccevola before dealt with, Sc. Plumieri and Sc. Kcenigii. 

 One of them, T. gnaphalodes, is found over the West Indies including 

 the Bahamas, in South Florida and the adjacent keys, in Bermuda, 

 and on the coasts of Mexico and Yucatan, but not apparently on 

 the Pacific coasts of the New World. The other, T. argentea, is 

 spread over most of the continental and insular coasts of the Indian 

 and Pacific Oceans in warm latitudes. It has also extended from 

 the East African to the West African coast, being found on the 

 shores of Lower Guinea (Oliver's and Dyer's Flora of Tropical Africa, 

 Vol. IV., sect 2, p. 29). Unlike Sccevola, however, the two species 

 never meet, being separated from each other by the breadths of the 

 Atlantic and Pacific Oceans. We have here also a New World 

 and an Old World species dividing the tropical beaches of the globe 

 between them, but the American species of Tournefortia is appro, 

 priated by the New World, whilst the American species of Sccevola 



