XXV SUMMARY OF CHAPTER 331 



almost the entire floras of the areas of Fiji-Samoa and of East 

 Polynesia. The whole of the tropical Pacific is here concerned, 

 and not a portion of it, as in the two preceding eras ; and in our 

 comparison we shall see that there are two, and not as heretofore 

 three, regions to be regarded — the Hawaiian in the North Pacific, 

 and the whole Polynesian area of the South Pacific extending from 

 Fiji to Tahiti. 



(2) Here the frugivorous bird has been the principal agent in 

 dispersing the plants, quite two-thirds of the genera possessing 

 drupes or berries that would attract such birds. 



(3) The genera representative of the first part of this era are 

 those which have only peculiar species in Hawaii, and are com- 

 posed in the South Pacific either entirely of peculiar species or 

 sometimes of a mixture of endemic and non-endemic species. It 

 is an era of complete isolation in Hawaii and often of a partial 

 connection between the groups of the southern region. Except to 

 some extent in the South Pacific, the dispersing agencies are 

 now no longer active between the groups. 



(4) Amongst the genera typical of this period are Pittosporum, 

 Gardenia, Psychotria, Cyrtandra, and Freycinetia. 



(5) The two genera of the Rubiaceae, Psychotria and Coprosma 

 (the last belonging to the mountain-flora), appear to be well suited 

 for the investigation of the effect on distribution of the geographical 

 position of the home of the genus, the first with 600 to 700 species 

 distributed over the tropics of the Old and New Worlds, the second 

 with some sixty species having its home in New Zealand. 



(6) From the Pacific Cyrtandras we derive the lessons that the 

 display of great formative power in a genus may not be a peculiarity 

 of an insular flora ; that the isolation of an oceanic archipelago does 

 not necessarily induce " endemism," but merely intensifies it ; and 

 that the production of new species within the limits of a genus like 

 Cyrtandra may be nearly as active on the mainland as in an island 

 in mid-ocean. 



(7) From the Freycinetias we learn that it may be possible to 

 connect the distribution of a genus of plants with that of a genus or 

 a family of birds. Just as in Chapter XXIV we endeavoured to 

 connect Coprosma and Porphyrio (the Purple Water- Hens), so we 

 here suggest a connection, in their range over the Pacific, between 

 the Freycinetias and the Meliphagidas (the Honey-eaters), a con- 

 nection that in the last case at least belongs to the past. 



(8) From the genus Phyllanthus we learn that genera with dry 

 fruits may be as widely distributed and may display the same 



