562 A NATURALIST IN THE PACIFIC 



stone, the empty seed-cavities cause it to be specifically lighter than water 

 whilst with the inland species the walls of the stone are so thick that the 

 empty spaces of the unfilled seed-cavities do not effect the same result. It 

 may be remarked that when the coast species grows in the inland plains 

 the buoyancy of the stone is preserved. 



Inland tree (P. serratifolia) 

 Coast tree (P. taitensis) 



One-seeded stones. 



73 per cent, 



92 



Two-seeded stones. 



23 per cent. 



Three-seeded stones. 



4 per cent 



NOTE 33 (page 63) 

 De Candolle's List of Plants dispersed exclusively by Currents 



Drepanocarpus lunatus ; Ecastaphyllum Brownei; Mucuna urens, D.C. ; 

 Tephrosia piscatoria ; Hibiscus tiliaceus ; Rhizophora mangle ; Guilandina 

 Bonduc, Linn. ; Ipomea pes caprse ; Canavalia obtxisifolia. 



I have experimented on the buoyancy of the fruits and seeds of all 

 these plants excepting the two first named. In five species the seeds float 

 in sea-water unharmed for several months. With Rhizophora it is the 

 floating seedling that disperses the plant. Neither the pods nor the seeds 

 of Tephrosia piscatoria are suited for dispersal by the currents. 



NOTE 34 (page 64) 



The Littoral Plants of the Easternmost Polynesian Islands 



Except in the case of Hernandia peltata my authority here is the 

 Botany of the " Challenger ^^ Expedition. Mr. J. H. Maiden gives some 

 further details of the flora of Pitcairn Island in a more recent paper 

 {Austral. Assoc. Rep., Melbourne, 1901, vol. 8), and Hernandia peltata is 

 included in his list. 



NOTE 35 (page 68) 



Distribution of the Littoral Plants with Buoyant Seeds or 

 Fruits that are found in the Fijian, Tongan, Samoan^ 

 Tahitian, and Hawaiian Groups 



This list probably contains nearly all the species of the Polynesian 

 region, but it is not implied that these plants have been recorded from all 

 the groups {vide iyifra). 



(a) Species found only in the Old World. — Calophyllum inophyllum, 

 Hibiscus diversifolius, Thespesia populnea, Heritiera littoralis, Kleinhovia 

 hospita, Carapa moluccensis, C. obovata, Smythea pacifica, Colubrina 

 asiatica, Mucuna gigantea, Erythrina indica, Strongylodon lucidum. 



