XXIV THE TAHITIAN MOUNTAIN FLORA 293 



Tahitian mountain-genera than with those of Hawaii. In the 

 Hawaiian mountain-flora, excluding, of course, the endemic genera, 

 it inckides about a fourth of the mountain-genera, which number 

 about thirty-eight or forty in all ; whilst in the Tahitian mountain- 

 flora it comprises six out of the eight genera. It may, indeed, be said 

 that the resemblance between the mountain-genera of Hawaii and 

 Tahiti is mainly restricted to genera that are found in high southern 

 latitudes, namely, Nertera, Coprosma, Cyathodes, and Astelia, the 

 only other genera linking the mountain-floras of both groups 

 together being Vaccinium and Luzula, which probably hail from 

 high northern latitudes. The agency of the frugivorous bird 

 is plainly marked in the case of five out of the six genera that 

 connect the cloud-capped peaks of Tahiti and Hawaii. In two of 

 these genera, Cyathodes and Nertera, the same species occurs 

 in both archipelagoes. 



The Mountain-flora of Rarotonga. — A word may here be said on 

 the representation of these mountain-genera in Rarotonga, a small 

 island 2,250 feet in height and about eight miles in length, which 

 is, however, the most important island of the Cook group. The 

 recent important explorations of Mr. Cheeseman show that its flora 

 is essentially Tahitian in character. As in Tahiti, the early age of 

 the Compositse and Lobeliaceae is well represented in the high 

 levels by peculiar species of Fitchia and Sclerotheca which are dis- 

 cussed in Chapters XXI and XXI I. On account, however, of its 

 relatively low altitude and its small size, we could not expect any 

 extensive representation of the eight non-endemic mountain-genera 

 of Tahiti. Yet three of these occur, a Tahitian species of Vac- 

 cinium (page 281) growing on its summits, whilst peculiar species of 

 Weinmannia (page 290) and Coprosma (page 295) are found in its 

 interior. The prevailing condition of many of the genera growing 

 in the higher levels is one of isolation, since other genera, like Pittos- 

 porum and Elaeocarpus, only possess peculiar species ; but seeing that 

 in several cases the species are closely allied to others found in the 

 Western Pacific, as in Samoa, Fiji, and the Kermadec group, it is 

 apparent that the period of isolation has not long commenced. 



The Mountain-Flora of the Fijian Region. 



Weinmannia, Saxifragaceae, Fiji and Samoa, n Derived from 

 Lagenophora, Compositai, Fiji. / New Zealand or 



Coprosma, Rubiaceae, Fiji. T from the 



Astelia, Liliace^, Fiji and Samoa. ) Antarctic flora. 



