xxn SUMMARY 267 



the case of the absence of the early Compositse, with the circum- 

 stance that the general distribution of these two orders over the 

 tropical Pacific occurred during the Tertiary submergence of these 

 archipelagoes. 



(7) These endemic genera of the Lobeliacese possess the same 

 facilities for dispersal that are owned by other genera with minute 

 seeds, such as Cyrtandra, &c., that are dispersed over the Pacific ; 

 but in the case of the Lobeliaceae the agencies of dispersal have 

 been for ages suspended. 



(8) This suspension is to be associated with the diverting of the 

 main stream of migration from its source in America, during the 

 early age of the Lobeliaceae and Compositse, to a source on the 

 Asiatic side of the Pacific. 



(9) The Hawaiian endemic genera other than those of the 

 Compositae and Lobeliacese arrange themselves in two groups — an 

 earlier group containing highly differentiated Caryophyllacese and 

 Labiatse, and belonging to the age of the Compositse and Lobelia- 

 ceae ; and a later group, characterised by Rubiaceae and Araliaceae, 

 which marks the close of the first era, as well as the change in the 

 main source of the plants from America to the Old World, the 

 beginning of the Hawaiian forests, the appearance of the Rubi- 

 aceous drupe, and the first active intervention of frugivorous birds. 



(10) Though there are no "difficult" or "impossible" fruits 

 (fruits, the dispersal of which is not easy to explain) amongst the 

 forty and odd endemic genera of Hawaii and Tahiti, it is note- 

 worthy that in some cases the fruits are seemingly little fitted for 

 dispersal now, and that this deterioration in capacity for dispersal 

 is to be frequently associated with more or less failure of the inter- 

 island dispersal in the case of Hawaii. 



(11) The interest associated with the Hawaiian endemic genera 

 fails to attach itself to those of Fiji, where genera only seem 

 to have become peculiar because they have failed at their sources 

 in the regions to the west. The endemic genera of the Compositae 

 and Lobeliaceae are here lacking, and this is true also of the 

 neighbouring Samoan and Tongan Groups, it being held that 

 the age of the general dispersion of these orders over the Pacific 

 corresponded with the Tertiary submergence of the archipelagoes 

 of the Western Pacific. Those of Fiji, which do not amount to ten 

 in number, belong to nearly as many orders and present a motley 

 collection such as one might look for in a group much less isolated 

 than Hawaii and exposed to wave after wave of migration from 

 the west. 



