330 A NATURALIST IN THE PACIFIC chap, 



same fashion. The drupes of Pritchardia pacifica are barely half 

 an inch in diameter. They are fitted by reason of their hard 

 crustaceous endocarp for dispersal by fruit-pigeons ; and I may 

 here add that these birds are known to distribute the fruits of 

 other palms, such as Kentia and Areca, in the islands of the 

 South Pacific {Bot. Chall. Exped. iv. 308, 312). 



Both in Hawaii and in Fiji I experimented on the capacity of 

 Pritchardia drupes for dispersal by the currents. Those of the 

 Hawaiian species, P. gaudichaudii, have when well dried a light 

 buoyant rather fibrous mesocarp which enables them to float in the 

 case of a good proportion of the fruits for at least five weeks. I 

 had no opportunity of testing the buoyancy of the fruits of P. 

 martii, another Hawaiian species ; but, judging from the existence 

 in the coats of a fibrous layer as described by Hillebrand, they 

 ought to display some floating power. The fruits of P. pacifica, 

 the South Pacific species, lack the light buoyant covering of the 

 Hawaiian, species above referred to, and display little or no floating 

 power even after drying for weeks. Looking at the results of these 

 experiments, it would seem that it is not impossible that Hawaii 

 received the genus through the agency of the currents ; but it 

 seems scarcely probable, since it could only have been derived 

 from America, and the American species grows in the interior of 

 the continent and not near the sea-border. The possibility of 

 course exists ; but I am inclined to attribute the presence of 

 Pritchardia in Hawaii to bird-agency. 



My position from the standpoint of dispersal with regard to 

 Pritchardia in the Pacific is this. The Hawaiian species I would 

 consider as American in origin. The Marquesan species, unless 

 recently described, still awaits detailed investigation. The West 

 Polynesian species of Fiji and Tonga, according to the principles of 

 distribution prevailing in the South Pacific, ought to hail from the 

 west. 



Summary. 



(i) Whilst the earliest age characterised by the Coniferas was 

 restricted to the Western Pacific, and whilst the following age of 

 the Compositae and Lobeliacese, mainly American in their affinities, 

 was concerned with the regions of Hawaii and Tahiti, we have now 

 to discuss the Malayan era during which the bulk of the plants 

 were derived from the nearest tropical regions of the Old World. 

 Here we have to deal with the low-level flora of Hawaii, that is to 

 say, with the plants of the levels below 4,000 or 5,000 feet, and with 



