xxm THE HAWAIIAN MOUNTAIN-FLORA 287 



the Chilian strawberry (Fragaria chilensis), the Sun-dew (Drosera 

 longifolia), Nertera depressa, and Luzula campestris, it may be 

 inferred that with the exception of Nertera they all reached 

 Hawaii from either the Asiatic or American sides of the North 

 Pacific, the last route being evident in the case of the strawberry. 

 Nertera depressa was probably derived from southern latitudes. 



Summary. 



(1) The second era of the flowering plants of the Pacific islands 

 is indicated by the non-endemic genera. Here also the isolating 

 influences have been generally active, and the work of dispersal is 

 in some regions largely suspended. Thus in Hawaii nearly half 

 the non-endemic genera possess only species that are restricted to 

 the group, whilst in Fiji and Tahiti about a fourth are thus 

 isolated. 



(2) The contrast in the elevations of the islands of the 

 Hawaiian, Tahitian, and Fijian regions is reflected in the 

 development of an extensive mountain-flora in Hawaii, in its 

 scanty development in Tahiti, and, excluding the Fijian conifers, 

 in a mere remnant in Fiji and Samoa. 



(3) The influence of isolation has been very active in the 

 Hawaiian mountains, since about two-thirds of the genera contain 

 only species confined to the group, and are thus disconnected from 

 the world outside. 



(4) Amongst these disconnected Hawaiian mountain genera, 

 Antarctic or New Zealand genera, like Acaena, Gunnera, Coprosma, 

 and Lagenophora, constitute nearly a third. The American element, 

 represented, for instance, by Sanicula and Sisyrinchium, is small ; 

 whilst the genera found on both sides of the Pacific form more 

 than one-half of the total, and include genera like Ranunculus, 

 Viola, Rubus, Artemisia, Vaccinium, and Plantago, that often 

 represent the flora of the temperate zone on the summits of 

 tropical mountains. Three-fourths of these genera are not found 

 either in Fiji or in Tahiti. 



(5) The proportion of the disconnected Hawaiian mountain 

 genera possessing seeds or seedvessels suited for dispersal in a 

 bird's plumage is very large, quite half belonging to this category ; 

 whilst only about a fourth have fruits that would be dispersed by 

 frugivorous birds. 



(6) The Hawaiian mountain genera that still remain in touch 

 with the external world through species found outside the islands 



