XXXIV GENERAL ARGUMENT AND CONCLUSION 519 



the non-endemic genera, displays much kinship with the Hawaiian 

 mountain flora; but this kinship is mainly confined to genera 

 from high southern latitudes, such as Coprosma, Cyathodes, 

 Astelia, &c. In the possession on its mountain slopes of the 

 three genera of the Conifers, Dammara, Podocarpus, and 

 Dacrydium, the Fijian region is distinguished from that of 

 Tahiti and Hawaii ; and it is assumed that tljey mark the site 

 of a continental area in the Mesozoic period, when the Tahitian 

 and Hawaiian groups did not exist. 



The era of the non-endemic genera, in so far as it is concerned 

 with the low-level flora of Hawaii and the floras in mass of the 

 areas of Fiji, Samoa and East Polynesia, is termed Malayan, 

 because many of the genera are thence derived. Here we are 

 dealing with all the oceanic groups of the tropical Pacific, and not 

 with a portion of them, as in the case of the Age of Coniferae, in 

 the Secondary period, that was limited to the Western Pacific, or 

 in the case of the Age of Compositae and Lobeliaceae that was 

 restricted during the Tertiary epoch to the Hawaiian and Tahitian 

 regions. The first part of this era, as is indicated by the endemic 

 species, is an age of complete isolation in Hawaii, and of partial 

 isolation in the groups of the southern region. Amongst the 

 genera typical of this period are Pittosporum, Gardenia, Psychotria, 

 Cyrtandra, and Freycinetia. A later period in this era of the 

 general dispersal of Malayan plants over the Pacific is one where 

 the extremely variable or polymorphous species plays a conspicuous 

 part, as represented in such genera as Alphitonia, Dodonaea, Metro- 

 sideros, Pisonia, and Wikstroemia, the general principle being that 

 each genus is at first represented by a widely ranging very variable 

 species, which ultimately ceases to wander and settles down, and 

 becomes the parent of different sets of species in the several 

 groups. 



The facts of distribution in this age of general dispersion are 

 just such as we might look for in the case of a general dispersal 

 over the oceanic groups of the Pacific, with the altitudes of the 

 islands playing a determining part. But it should be remarked 

 that the greater number of the genera that have entered the Pacific 

 from the Old World have not advanced eastward of the Fijian 

 region, half of the Fijian genera not occurring in the Hawaiian 

 and Tahitian regions. The explanation of this is to be found, not 

 in any lack of capacities for dispersal, but in a want of oppor- 

 tunities. The story of plant-distribution in the Pacific is bound 

 up with the successive stages of decreasing activity in the dispers- 



